Dapsone in dermatology and beyond

Surgical Treatment of Pyoderma Gangrenosum with Negative Pressure Wound Therapy and Skin Grafting, Including Xenografts: Personal Experience and Comprehensive Review on 161 Cases

Significance: Pyoderma gangrenosum (PG) is a rare debilitating autoinflammatory ulcerative skin disease. No gold standard has been established for the treatment of PG. The role of surgical interventions and negative pressure wound therapy (NPWT) was discussed controversially until recently as these procedures might pose a trigger to further aggravate the condition. Recent Advances: Recent advances confirm the paradigm change that a surgical approach of PG with split thickness skin grafting (STSG) secured by NPWT is a safe and valuable treatment if performed under adequate immunosuppression. We elaborate this on the hand of a broad literature search retrieving 101 relevant articles describing 138 patients complemented with our personal experience on 23 patients, including 2 patients treated with a porcine xenodressing. Critical Issues: A wide range of surgical approaches have been reported, including xenografts. Treatment was finally successful in 86%, including the xenotransplant cases. Ten percent improved and failures were mainly reported without immunosuppression. Despite halting the inflammatory process, NPWT alone, without skin grafting, does not much accelerate healing time. The best surgical approach appears to be STSG fixed with NPWT as this leads to higher skin graft take. There remains the problem of the chronic nature of PG and the recurrence after tapering of immunosuppression or trauma; therefore, a sustained immunosuppressive treatment is suggested. Future Directions: While surgical treatment is supported by the published data, the exact immunosuppression is still evolving. Due to deeper insights into pathogenesis and growing clinical reports, a broader utilization of biologic treatments and a shift from tumor necrosis factor (TNF)-alpha to interleukin (IL)-12/23 or IL-23 antibodies alone are predictable, as IL-12/23 antibodies show good clinical responses with fewer side effects. The positive results with porcine xenodressings might be due to immunological effects of the xenomaterial; they appear promising, but are preliminary and should be confirmed in a larger patient collective.

Dapsone in the Management of Pemphigus and Pemphigoid: Rediscovery of its Long-Lost Efficacy

Introduction

Autoimmune mucocutaneous blistering dermatoses (AMCBD) are a group of disorders characterized by the production of autoantibodies that target specific adhesion molecules of the skin and/or mucous membranes. As a result, there is blister formation on the skin with or without mucous membrane involvement. Systemic corticosteroids have been used as the mainstay of treatment in AMCBD. However, due to the debilitating side effects associated with their use, there is significant morbidity and mortality, especially on the fragile elderly patients. Although the efficacy of dapsone in the treatment of AMCBD was identified decades ago, few recent studies shed light on that. Hence, further studies are needed to evaluate the efficacy of dapsone as a single agent in maintaining disease remission in patients with AMCBD.

Materials and methods

An observational retrospective study was performed. Patients with a known diagnosis of bullous pemphigoid (BP) or pemphigus vulgaris (PV) who are treated with dapsone with or without low-dose systemic corticosteroids were included in the study, and their medical files were reviewed. 

Results

A total of seven patients were included (three males and four females). All patients showed a satisfactory response to dapsone, achieving disease remission in a short period of time with no serious side effects necessitating treatment cessation.

Conclusions

Our findings support that dapsone may have a corticosteroid-sparing effect in the management of AMCBD. Further studies are warranted to confirm our findings.

A theoretical study of chemical bonding and topological and electrostatic properties of the anti-leprosy drug dapsone

The theoretical charge density study for the gas phase of anti-leprosy drug Dapsone has been carried out in the light of the theory of atoms in molecules using density functional theory employing B3LYP(6-311G++(d, p) hybrid functional completed with dispersion corrections. The Hirshfeld surface analysis as well as fingerprint plots has been utilized to visualize and quantify the intermolecular contacts present in the molecule. The topological properties such as electron density and its Laplacian, delocalization index have been elucidated to throw light into the chemical bonding and atomic and molecular details. The electron localization function has been used to visualize and deduce information on the lone pair and the subshells of the Cl atom. The electrostatic potential visualizes the positive and negative electrostatic potential regions which are susceptible to nucleophilic and electrophilic attack. On the whole, this study provides an exact mechanism, interaction, and topological and electrostatic properties of the drug through theoretical insights which all will be a platform for our further investigation of the interaction between dapsone and dihydropteroate synthase (DHPS).

Protective effect of dapsone against renal ischemia-reperfusion injury in rat

Background: Ischemia/reperfusion can cause injury to tissues and compromise functionality of organs due to inflammatory processes. Significantly, development of these effects in kidney tissue has been a challenging issue that leads to acute renal injury. In this study, anti-inflammatory, anti-oxidative, and protective features of dapsone on kidney ischemia/reperfusion injury were investigated.Material and methods: Renal ischemia was induced in rats by bilateral renal arteries clamping for 45 min followed by 24 h reperfusion phase. The effects of different doses of dapsone (1, 3, 10 mg/kg) on ischemia/reperfusion injury in kidney tissue were investigated by targeting BUN, Creatinine, LDH, MDA, MPO, IL-1β, TNF-α, and NFκB. In addition histopathological examination was performed by H&E staining method.Results and discussion: Comparing the findings of this study showed significant reduction in BUN and LDH in 10 mg/kg dapsone received groups, and Cr, MDA, and MPO in 3 mg/kg dapsone received groups. The serum level of TNF-α was significantly decreased with both doses of 3 and 10 mg/kg dapsone. The same results were observed in the serum level of IL-1β and NFκB. Besides, remarkable improvement in histological damages was also observed with dapsone treatment.Conclusion: These results support the hypothesis that the positive effects of dapsone on the renal ischemia/reperfusion injury are mediated by modulating inflammatory cascades.

Dapsone as treatment adjunct in ARDS

Multiple pharmacological interventions tested over the last decades have failed to reduce ARDS mortality. This short note recounts past data indicating that (i) neutrophils home along an IL-8 gradient, (ii) in ARDS, massive neutrophil accumulation and degranulation in and along bronchoalveolar spaces contributes to damage and hypoxia, (iii) large increases in IL-8 are one of the chemotaxic signals drawing neutrophils to the ARDS lung, and (iv) old data from dermatology and glioblastoma research showed that the old drug against Hansen’s disease, dapsone, inhibits neutrophils’ chemotaxis to IL-8. Therefore dapsone might lower neutrophils’ contributions to ARDS lung pathology. Dapsone can create methemoglobinemia that although rarely problematic it would be particularly undesirable in ARDS. The common antacid drug cimetidine lowers risk of dapsone related methemoglobinemia and should be given concomitantly.

Evaluation of Prospective HLA-B*13:01 Screening to Prevent Dapsone Hypersensitivity Syndrome in Patients With Leprosy

Importance

Dapsone hypersensitivity syndrome (DHS) is the most serious adverse reaction associated with dapsone administration and one of the major causes of death in patients with leprosy, whose standard treatment includes multidrug therapy (MDT) with dapsone, rifampicin, and clofazimine. Although the HLA-B*13:01 polymorphism has been identified as the genetic determinant of DHS in the Chinese population, no studies to date have been done to evaluate whether prospective HLA-B*13:01 screening could prevent DHS by identifying patients who should not receive dapsone.

Objective

To evaluate the clinical use of prospective HLA-B*13:01 screening for reduction of the incidence of DHS by excluding dapsone from the treatment for patients with HLA-B*13:01-positive leprosy.

Design, Setting, and Participants

A prospective cohort study was conducted from February 15, 2015, to April 30, 2018, in 21 provinces throughout China. A total of 1539 patients with newly diagnosed leprosy were enrolled who had not received dapsone previously. After excluding patients who had a history of allergy to sulfones or glucose-6-phosphate dehydrogenase deficiency, 1512 individuals underwent HLA-B*13:01 genotyping. All of the patients were followed up weekly for the first 8 weeks after treatment to monitor for adverse events.

Exposures

Patients who were HLA-B*13:01 carriers were instructed to eliminate dapsone from their treatment regimens, and noncarrier patients received standard MDT.

Main Outcomes and Measures

The primary outcome was the incidence of DHS. The historical incidence rate of DHS (1.0%) was used as a control.

Results

Among 1512 patients (1026 [67.9%] men, 486 [32.1%] women; mean [SD] age, 43.1 [16.2] years), 261 (17.3%) were identified as carriers of the HLA-B*13:01 allele. A total of 714 adverse events in 384 patients were observed during the follow-up period. Dapsone hypersensitivity syndrome did not develop in any of the 1251 patients who were HLA-B*13:01-negative who received dapsone, while approximately 13 patients would be expected to experience DHS, based on the historical incidence rate of 1.0% per year (P = 2.05 × 10-5). No significant correlation was found between other adverse events, including dermatologic or other events, and HLA-B*13:01 status.

Conclusions and Relevance

Prospective HLA-B*13:01 screening and subsequent elimination of dapsone from MDT for patients with HLA-B*13:01-positive leprosy may significantly reduce the incidence of DHS in the Chinese population.

Recovery of Dementia Syndrome following Treatment of Brain Inflammation

Aim/Background

This research aims to prevent progression from mild cognitive impairment (MCI) to Alzheimer's disease. A Japanese study of leprosy patients revealed that the incidence of dementia in leprosy patients was lower than that in patients taking dapsone who had never been treated. But a similar study the following year refuted the finding of less dementia in leprosy patients taking dapsone. According to conflicting reports, Mycobacterium leprae was a factor in reducing the incidence of Alzheimer's disease. Thus, we formed a hypothesis that if dapsone is administered to patients without leprosy but with MCI and the prophylactic effect of dementia syndrome is observed over a long period of time, we can determine whether dapsone can prevent the progression of MCI to dementia syndrome. If dementia does not occur after treating inflammation in brain cells while dementia develops after a certain long-term period (usually within 2–3 years), brain cell inflammation can be demonstrated as the cause of dementia.

Methods

This is a prospective cohort research. We report on an elderly patient diagnosed with MCI from February 2008 to January 2019. The patient took dapsone 100 mg once a day from 2010 to 2015 for the treatment of MCI. Since 2016, the production of dapsone has ceased in Korea. In June 2018, the patient was diagnosed with Alzheimer's disease. The patient took Aricept for the treatment of Alzheimer's disease but complained of serious side effects. And dapsone was re-administered to the patient from November 2018.

Results

The patient recovered to MCI and improved her daily life owing to the treatment with dapsone. The drug controls the inflammatory response in the brain, irrespective of whether proteins are deposited in neurons.

Conclusions

This finding means that dementia syndrome is an inflammatory disease. This research suggests that diagnostic criteria for Alzheimer's disease should be based on the presence or absence of inflammation in neurons. Because inflammation in neurons can occur in middle age due to various causes, we can treat inflammation in neurons and prevent and treat dementia syndrome, including Alzheimer's disease.

Dioscin alleviates lipopolysaccharide-induced acute lung injury through suppression of TLR4 signaling pathways

Aim: Acute lung injury (ALI) is a life-threatening inflammatory syndrome that lacks an effective therapy. Dioscin, a natural steroid saponin isolated from a variety of herbs, could serve as an anti-inflammatory agent, as suggested in previous reports. The purpose of this study was to explore the effects of dioscin on lipopolysaccharide (LPS)-induced ALI and validate the potential mechanisms.Materials and Methods: An ALI model was induced by intratracheal administration of LPS. Dioscin (20, 40, and 80 mg/kg) was administered intragastrically once daily for seven consecutive days prior to LPS challenge.Results: Our data revealed that dioscin significantly suppressed LPS-induced lung pathological changes, pulmonary capillary permeability, pulmonary edema, inflammatory cell infiltration, myeloperoxidase (MPO) activity, and cytokine production, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and keratinocyte chemoattractant (KC). Moreover, dioscin inhibited LPS-induced nuclear factor-kappaB (NF-κB) activation as well as Toll-like receptor 4 (TLR4) expression.Conclusions: In brief, the results indicated that dioscin alleviates LPS-induced ALI through suppression of TLR4 signaling pathways.

Update on the use of dapsone in dermatology

Dapsone (4,4'-diaminodiphenylsulfone) is the only remaining sulfone used in anthropoid therapeutics and is commercially available as an oral formulation, an inhaled preparation, and a 5% or 7.5% cream. Dapsone has antimicrobial effects stemming from its sulfonamide-like ability to inhibit the synthesis of dihydrofolic acid. It also has anti-inflammatory properties such as inhibiting the production of reactive oxygen species, reducing the effect of eosinophil peroxidase on mast cells and down-regulating neutrophil-mediated inflammatory responses. This allows for its use in the treatment of a wide variety of inflammatory and infectious skin conditions. Currently in dermatology, the US Food and Drug Administration (FDA)-approved indications for dapsone are leprosy, dermatitis herpetiformis, and acne vulgaris. However, it proved itself as an adjunctive therapeutic agent to many other skin disorders. In this review, we discuss existing evidence on the mechanisms of action of dapsone, its FDA-approved indications, off-label uses, and side effects.

The KAAACI/KDA Evidence-Based Practice Guidelines for Chronic Spontaneous Urticaria in Korean Adults and Children: Part 2. Management of H1-Antihistamine-Refractory Chronic Urticaria

Quite a few patients with chronic spontaneous urticaria (CSU) are refractory to H₁-antihistamines, even though the dose of H₁-antihistamines is increased up to 4-fold. CSU that is not controlled with H₁-antihistamines results in increased disease burden. Several immunomodulators have been used to manage these patients. The guidelines reported herein are connected to Part 1 of the KAAACI/KDA Evidence-Based Practice Guidelines for Chronic Spontaneous Urticaria in Korean Adults and Children, and aimed to provide evidence-based recommendations for the management of H₁-antihistamine-refractory CSU. Part 2 focuses on the more commonly used additional treatment options for refractory CSU, including omalizumab, cyclosporine, leukotriene receptor antagonist, dapsone, methotrexate, and phototherapy. The evidence to support their efficacy, dosing, safety, and selection of these agents is systematically reviewed. To date, for patients with refractory CSU, the methodologically sound data to evaluate the use of omalizumab has been growing; however, the evidence of other immunomodulators and phototherapy is still insufficient. Therefore, an individualized stepwise approach with a goal of achieving complete symptom control and minimizing side effects can be recommended. Larger controlled studies are needed to elevate the level of evidence to select a rational therapeutic agent for patients with refractory CSU.

Evaluation of Skin Permeation and Retention of Topical Dapsone in Murine Cutaneous Leishmaniasis Lesions

The oral administration of dapsone (DAP) for the treatment of cutaneous leishmaniasis (CL) is effective, although serious hematological side effects limit its use. In this study, we evaluated this drug for the topical treatment of CL. As efficacy depends on potency and skin penetration, we first determined its antileishmanial activity (IC50 = 100 μM) and selectivity index in vitro against Leishmania major-infected macrophages. In order to evaluate the skin penetration ex vivo, we compared an O/W cream containing DAP that had been micronized with a pluronic lecithin emulgel, in which the drug was solubilized with diethylene glycol monoethyl ether. For both formulations we obtained similar low flux values that increased when the stratum corneum and the epidermis were removed. In vivo efficacy studies performed on L. major-infected BALB/c mice revealed that treatment not only failed to cure the lesions but made their evolution and appearance worse. High plasma drug levels were detected and were concomitant with anemia and iron accumulation in the spleen. This side effect was correlated with a reduction of parasite burden in this organ. Our results evidenced that DAP in these formulations does not have an adequate safety index for use in the topical therapy of CL.

Dapsone-induced hepatic complications: it's time to think beyond methemoglobinemia

Drug-induced liver injury is an important cause of hepatotoxicity and poses a challenging clinical problem with respect to both diagnosis and management. Patients susceptible to hepatotoxicity on exposure to dapsone is constantly on the rise. Dapsone (4,4'-diaminodiphenylsulfone) is clinically used alone or in combination with rifampicin for the treatment of a variety of dermatological disorders such as acne, dermatitis herpetiformis, psoriasis, Toxoplasma gondii infections, leprosy and pneumocystis carinii pneumonia in AIDS patients. However, the clinical use of dapsone is limited because of dose-dependent adverse hematological reactions. The cholestatic injury caused by dapsone and its N- hydroxylated metabolites hinders bile flow and causes oxidative stress and hepatic necrosis, further, leading to hemolysis responsible for hepatitis due to iron overload in the liver. Hence, clinicians' awareness of the hepatotoxic potential of dapsone is highly warranted.

In vitro Antimicrobial Activity of Acne Drugs Against Skin-Associated Bacteria

Acne is a common skin affliction that involves excess sebum production and modified lipid composition, duct blockage, colonization by bacteria, and inflammation. Acne drugs target one or more of these steps, with antibiotics commonly used to treat the microbial infection for moderate to severe cases. Whilst a number of other acne therapies are purported to possess antimicrobial activity, this has been poorly documented in many cases. We conducted a comparative analysis of the activity of common topical acne drugs against the principal etiological agent associated with acne: the aerotolerant anaerobic Gram-positive organism Propionibacterium acnes (recently renamed as Cutibacterium acnes). We also assessed their impact on other bacteria that could also be affected by topical treatments, including both antibiotic-sensitive and antibiotic-resistant strains, using broth microdilution assay conditions. Drugs designated specifically as antibiotics had the greatest potency, but lost activity against resistant strains. The non-antibiotic acne agents did possess widespread antimicrobial activity, including against resistant strains, but at substantially higher concentrations. Hence, the antimicrobial activity of non-antibiotic acne agents may provide protection against a background of increased drug-resistant bacteria.

Folic Acid Antagonists: Antimicrobial and Immunomodulating Mechanisms and Applications

: Bacterial, protozoan and other microbial infections share an accelerated metabolic rate. In order to ensure a proper functioning of cell replication and proteins and nucleic acids synthesis processes, folate metabolism rate is also increased in these cases. For this reason, folic acid antagonists have been used since their discovery to treat different kinds of microbial infections, taking advantage of this metabolic difference when compared with human cells. However, resistances to these compounds have emerged since then and only combined therapies are currently used in clinic. In addition, some of these compounds have been found to have an immunomodulatory behavior that allows clinicians using them as anti-inflammatory or immunosuppressive drugs. Therefore, the aim of this review is to provide an updated state-of-the-art on the use of antifolates as antibacterial and immunomodulating agents in the clinical setting, as well as to present their action mechanisms and currently investigated biomedical applications.

Autologous fibroblasts for the treatment of cutaneous loxoscelism: First experience

Several treatments have been described for cutaneous loxoscelism (CL), but the quality of available evidence is insufficient for the elaboration of a therapeutic consensus. Dapsone has shown beneficial effects on stopping the inflammatory phenomenon and accelerating the recovery. It is recommended to start dapsone once the visceral involvement is ruled out if glucose-6-phosphate dehydrogenase levels are normal. Autologous fibroblast (AF) therapy is a novel therapy that has been successfully used in bioengineering as skin substitutes for surgical wounds and burns, diabetic and pressure ulcers, and other aesthetic purposes. Interestingly, there are no reports of AFs in CL. We present a case of CL in which the necrotic process was stabilised with dapsone, but the healing of the ulcer was not achieved. Three weekly applications of AFs 100 000/cm² were performed on a biocompatible polymer matrix, with optimal response within 2 months. This represents the first report of AFs in CL, setting the stage for future studies.

Dapsone in a Large Tertiary Center: Outdated Therapeutic Option or Timeless Agent?

BACKGROUND

The ancient drug dapsone has antimicrobial and anti-inflammatory features. In dermatology, dapsone is primarily used for neutrophil-dominant skin diseases. However, real-life data assessing the long-term efficacy of dapsone across multiple dermatological diseases is missing. -Objectives: To determine the efficacy and safety of dapsone in patients with inflammatory skin diseases treated at the Department of Dermatology of the University Hospital Zurich.

METHODS

The hospital database was searched for patients treated with dapsone in the last 20 years (from January 1, 1998, to December 31, 2017). Overall, 175 patients were included in our study.

RESULTS

Thirty-four patients received dapsone for eosinophilic dermatoses, 82 for neutrophilic dermatoses and 59 for other dermatoses. After 3 months, 8% of all patients reached complete remission, 40.6% showed improvement, 30.3% had stable disease, and only 9.1% had disease progression. Final treatment evaluation revealed complete response in 13.2%, disease improvement in 47.4%, stable disease in 25.7% and disease progression in only 12.0%. Patients who showed remission or improvement after 3 months were significantly older than patients with stable or progressive disease. In addition, remission after 3 months was associated with a significantly lower dose of dapsone compared to improvement only. Hemolysis was the most common adverse event (21.7%).

CONCLUSIONS

Our data show that dapsone is a valid treatment option in various dermatological diseases, leading to a favorable response in the vast majority of patients. In addition, it is well tolerated, safe and inexpensive. Randomized, controlled trials are needed to further elucidate the role of this high-potential drug.

An update on generalized pustular psoriasis

Introduction: Generalized pustular psoriasis (GPP) is a rare, severe relapsing/remitting, multisystem disease that can be difficult to treat. Recent clinical, histological, and genetic evidence suggests that GPP is a distinct clinical entity from plaque psoriasis and requires a separate diagnosis. The interleukin-36 pathway appears to be central to GPP pathogenesis. As no therapeutic agents have been approved for GPP to date in the United States or Europe, the introduction of anti-IL-36 therapies may change disease management. Areas covered: Using PubMed and Google Scholar, we reviewed the literature for articles related to GPP, psoriasis, and the genetics, pathogenesis, and treatment thereof. Expert opinion: New therapeutic options and updated guidelines for GPP treatment are needed. Ideal agents would have rapid onset of action and rapid time to achieve disease clearance, have the ability to prevent acute flares and avert recurrence, and possess a favorable safety profile. Such therapies should be readily accessible via approval or listing on formularies. Scoring systems to establish GPP disease burden and objective outcome measures could also help with further evaluation of therapies and treatment access issues. IL-36 remains a promising target, as supported by early phase data suggesting efficacy and safety for a novel anti-IL-36 therapy.

Experimental and computational approaches to rationalise multicomponent supramolecular assemblies: dapsone monosolvates

The monosolvate crystal energy landscapes of dapsone (DDS) including the solvents carbon tetrachloride, acetone, cyclohexanone, dimethyl formamide, tetrahydrofuran, methyl ethyl ketone, 1,2-dichloroethane, 1,4-dioxane, dichloromethane and chloroform were established using experimental and computational approaches. To rationalise and understand solvate formation, solvate stability and desolvation reactions a careful control of the experimental crystallisation and storage conditions, a range of thermoanalytical methods and crystal structure prediction were required. Six of the eight DDS monosolvates are reported and characterised for the first time. Structural similarity and diversity of the at ambient conditions unstable monosolvates were apparent from the computed crystal energy landscapes, which had the experimental packings as lowest energy structures. The computed structures were used as input for Rietveld refinements and isostructurality of four of the monosolvates was confirmed. Packing comparisons of the solvate structures and molecular properties of the solvent molecules indicated that both size/shape of the solvent molecule and the possible DDSsolvent interactions are the important factors for DDS solvate formation. Through the combination of experiment and theory solvate stability and structural features have been rationalised.

Experimental dapsone administration induces infertility in male Wistar rats: Mechanisms and clinical implications

Dapsone (4, 4'-diaminodiphenylsulfone, DDS) is a potent anti-inflammatory and antibacterial compound which has been used in the treatment of leprosy, vasculitis and dermatitis herpetiformis, lupus erythematosus profundus and even as an antimalarial in combination with proguanil. This study investigated the effect of the administration of dapsone on the reproductive activities of male rats using in vivo and in vitro techniques. In the in vivo study, dapsone was administered orally to male Wistar rats for 5 days or 6 weeks after which their body weight, relative reproductive organ weights, sperm parameters and reproductive hormones were determined while testicular and epididymal histology were also assessed. Data were compared using analysis of variance and Students-Newman-Keuls multiple comparison test. For the in vitro study, Sertoli cells were cultured and treated with varying doses of dapsone at different durations, thereafter Sertoli cell viability and nuclei integrity were determined. Also, the genetic expressions of Glial cell line-derived neurotrophic factor (GDNF) and transferrin were assessed. The results obtained from the in vivo study showed a duration-dependent significant decrease in body and reproductive organ weights, sperm parameters and serum testosterone concentration. Testicular and epididymal histology also showed duration-dependent degenerative changes. However, all these changes were restored towards control values in the recovery experiment. The viability and deoxyribonucleic acid (DNA) integrity of the treated Sertoli cells showed dose and duration-dependent adverse effects while GDNF and transferrin showed normal genetic expressions. These results suggest that dapsone could induce male reproductive stress by affecting testicular and epididymal structure and function.

Indications and efficiency of dapsone in IgA vasculitis (Henoch-Schonlein purpura): case series and a review of the literature

Immunoglobulin A (IgA) vasculitis (Henoch-Schonlein purpura (HSP)) is the most common vasculitis in children. It is characterized by purpuric rash, arthritis, gastrointestinal, and/or renal involvement. Spontaneous resolution is the typical outcome. In chronic cutaneous manifestations of IgA vasculitis, dapsone seems to show a good effectiveness. Multiple case reports and case series about dapsone in chronic IgA vasculitis are available. However, no clear evaluation of its indications, its effectiveness, or its usage guidelines (optimal dosage or duration of treatment) is available. We reviewed the published cases of IgA vasculitis treated by dapsone and compared them with 2 similar cases that we encountered. Seventeen patients (ranging from 22 months old to 16 years old) with severe or persistent clinical signs of IgA vasculitis were included. Dapsone showed good results on the resolution of cutaneous lesions but not on renal manifestations. Complications (methemoglobinemia) were observed on 1 patient. Half of the patients relapsed after treatment discontinuation. The difference between the time lapse before initiation and the duration of the treatment was not significant.Conclusion: We suggest that dapsone can have a positive effect in chronic IgA vasculitis when cutaneous manifestations last more than 6 weeks at the dosage of 1-2 mg/kg once per day during 1 week. What is Known: • IgA vasculitis or Henoch-Schonlein purpura is the most common vasculitis in children and affects mostly small vessels of the skin, kidney, and gastrointestinal tract. It resolves spontaneously in most of the cases. Exceptionally, cutaneous lesions can last several weeks. • Dapsone is a bacteriostatic antibacterial sulfonamide drug found to be effective in the treatment of some inflammatory dermatological diseases like IgA vasculitis. What is New: • Dapsone is effective against chronic purpuric lesion (> 6 weeks) at the minimal dose of 1 mg/kg/day. • Relapse occurs frequently after discontinuation but responds after a second course of treatment. A longer duration of treatment or a delay in treatment by dapsone does not seem to influence the relapse rate.

Bilosomes as a novel carrier for the cutaneous delivery for dapsone as a potential treatment of acne: preparation, characterization and in vivo skin deposition assay

In our study, the potential of bilosomes as novel vesicular carrier for the cutaneous delivery of the sulphone compound, Dapsone, for topical treatment of acne was investigated. The effect of different formulation variables (type and concentration of bile salt, and molar ratio of Span 60:cholesterol) on the properties of DPS-loaded bilosomes was investigated using a full factorial design. Design Expert software was used for data analysis and optimization of DPS-loaded bilosomes. The optimized bilosomes, chosen on the basis of their superior properties giving maximum entrapment, in vitro release after different time intervals and RE% with minimum vesicle size. Results showed that the bilosome system prepared using Span^® 60: Cholesterol (5:1) and containing 0.25 M sodium deoxycholate as the bile salt was found to obey these criteria, with a desirability value of 0.637. Therefore, this system was chosen for further assessment for its morphological properties, zeta potential, thermal analysis using differential scanning calorimetry and X-ray diffractometry. Results revealed that the chosen bilosomes were spherical in shape with no aggregation, and contained DPS in a molecularly dispersed amorphous form. Finally, the capability of the optimized DPS-loaded bilosomes to deliver DPS through rat skin layers will be investigated and compared with that of DPS alcoholic solution. Results showed that the amounts of DPS retained in the skin treated with DPS-loaded bilosomes, and DPS alcoholic solution after 24 h were found to be 170.57 ± 55.12 and 120.24 ± 10.7 µg/mL, respectively, representing about 1.5-fold higher drug retained in the bilosomes-treated skin. Finally, the safety and the tolerability of the prepared bilosomes were assessed using histopathological examination, and revealed that the control untreated skin sections and skin sections treated with DPS-loaded bilosomes showed normal histological structures characterized by absence of defects or inflammation. Such results can be considered a good addition in the field of pharmaceutical drug delivery for effective topical therapy of acne.

DDS promotes longevity through a microbiome-mediated starvation signal

The antibiotic diaminodiphenyl sulfone (DDS) is used in combination with other antibiotics as a first line treatment for leprosy. DDS has been previously reported to extend lifespan in Caenorhabditis elegans through inhibition of pyruvate kinase and decreased mitochondrial function. Here we report an alternative mechanism of action by which DDS promotes longevity in C. elegans by reducing folate production by the microbiome. This results in altered methionine cycle metabolite levels mimicking the effects of metformin and lifespan extension that is dependent on the starvation- and hypoxia-induced flavin containing monoxygenase, FMO-2.

In vitro assessment of antifungal, antibacterial, and antiprotozoal drugs against clinical isolates of Conidiobolus lamprauges

We have determined the in vitro activity of antifungal, antibacterial, and antiprotozoal drugs alone and in combination against seven Conidiobolus lamprauges clinical isolates. The assays were based on the M38-A2 protocol and the checkerboard microdilution method. The lowest inhibitory concentrations were observed for amphotericin B, miconazole (MCZ), terbinafine, and miltefosine (MTF) (MIC range 0.25-1; 2-8; 0.25-2; 2-16 μg/ml, respectively). The main synergism observed was through the combination of azithromycin (AZI)+MTF and dapsone (DAP)+MTF (100%), AZI+DAP (85.7%), AZI+MCZ (57.1%) as well as MCZ plus CTX and DAP (42.9%). The in vitro activities suggest that the combination of MTF and AZI or DAP are promising candidate therapies for conidiobolomycosis.

Drug repurposing: a promising tool to accelerate the drug discovery process

Traditional drug discovery and development involves several stages for the discovery of a new drug and to obtain marketing approval. It is necessary to discover new strategies for reducing the drug discovery time frame. Today, drug repurposing has gained importance in identifying new therapeutic uses for already-available drugs. Typically, repurposing can be achieved serendipitously (unintentional fortunate observations) or through systematic approaches. Numerous strategies to discover new indications for FDA-approved drugs are discussed in this article. Drug repurposing has therefore become a productive approach for drug discovery because it provides a novel way to explore old drugs for new use but encounters several challenges. Some examples of different approaches are reviewed here.

A Case of Dapsone-Induced Severe Agranulocytosis Causing Life-Threatening Skin Sepsis in a Sri Lankan Child with Borderline Leprosy: A Success Story!

Leprosy is a common skin disease in Sri Lanka which is being increasingly diagnosed due to the existing successful public health programme. Dapsone is a drug which holds unique pharmacological properties where it serves as both anti-inflammatory and antimicrobial agents. Of its main adverse effects, agranulocytosis is a serious consequence which is reported mainly in adults and elderly. We report a 7-year-old child who sustained life-threatening skin and subcutaneous tissue sepsis because of dapsone-induced agranulocytosis. Besides, this case highlights the importance of meticulous monitoring of cell counts due to the risk of neutropenia and the natural history of cell recovery following occurrence of neutropenia. Though high mortality rate has been described in most of the similar cases reported, the child we describe made a complete recovery following severe neutropenic sepsis.

Pharmacogenomics/updated for precision medicine in dermatology

Pharmacogenomics, a key part of precision medicine, has the potential to tailor drug therapy with the high safety margins and optimized response. Before the Human Genome Project in 2003, articles on pharmacogenomics were limited. The last 15 years have seen significant growth in the field, with gene variant discoveries that play essential roles in individuals' drug response. Dermatology has started to take advantage of this information. This overview shows how pharmacogenomic databases have expanded in the treatment of skin diseases and provides a list of current dermatologic drugs with their FDA-approved biomarkers and clinical implementation.

Dapsone Form V: A Late Appearing Thermodynamic Polymorph of a Pharmaceutical

Five anhydrate polymorphs (forms I-V) and the isomorphic dehydrate (Hy_dehy) of dapsone (4,4'-diaminodiphenyl sulfone or DDS) were prepared and characterized in an interdisciplinary experimental and computational study, elucidating the kinetic and thermodynamic stabilities, solid form interrelationships, and structural features of the known forms I-IV, the novel polymorph form V, and Hy_dehy. Calorimetric measurements, solubility experiments, and lattice energy calculations revealed that form V is the thermodynamically stable polymorph from absolute zero to at least 90 °C. At higher temperatures, form II, and then form I, becomes the most stable DDS solid form. The computed 0 K stability order (lattice energy calculations) was confirmed with calorimetric measurements as follows, V (most stable) > III > Hy_dehy > II > I > IV (least stable). The discovery of form V was complicated by the fact that the metastable but kinetically stabilized form III shows a higher nucleation and growth rate. By combining laboratory powder X-ray diffraction data and ab initio calculations, the crystal structure of form V ( P2₁/ c, Z' = 4) was solved, with a high energy DDS conformation allowing a denser packing and more stable intermolecular interactions, rationalizing the formation of a high Z' structure. The structures of the forms I and IV, only observed from the melt and showing distinct packing features compared to the forms II, III, and V, were derived from the computed crystal energy landscapes. Dehydration modeling of the DDS hydrate led to the Hy_dehy structure. This study expands our understanding about the complex crystallization behavior of pharmaceuticals and highlights the big challenge in solid form screening, especially that there is no clear end point.

Association Between HLA-B*1301 and Dapsone-Induced Cutaneous Adverse Drug Reactions: A Systematic Review and Meta-analysis

Importance

Dapsone-induced hypersensitivity syndrome (DHS) is a life-threatening adverse drug reaction. Based on available epidemiologic studies, HLA genotypes may play an important role in DHS.

Objective

To assess the association between HLA-B*1301 and dapsone-induced cutaneous adverse drug reactions (cADRs).

Data Sources

Human studies investigating associations between HLA-B*1301 and dapsone-induced cADRs were systematically searched without language restriction from the inception of each database until September 12, 2017, in PubMed, the Human Genome Epidemiology Network), and the Cochrane Library. Combinations of HLA genotypes, dapsone, and synonymous terms were used; reference lists were searched in selected articles.

Study Selection

Two reviewers identified studies investigating the associations between HLA-B*1301 and dapsone-induced cADRs that reported sufficient data for calculating the frequency of HLA-B*1301 carriers among case and control patients, in which all patients received dapsone before HLA-B*1301 screening. An initial search of the databases identified 391 articles, of which 3 studies (2 in Chinese populations and 1 in a Thai population) met the inclusion criteria.

Data Extraction and Synthesis

Overall odds ratios (ORs) with 95% CIs were calculated using a random-effects model to determine the association between HLA-B*1301 and dapsone-induced cADRs. Subgroup analyses by type of cADR were also performed. PRISMA guidelines were used to abstract and assess data.

Main Outcomes and Measures

Primary outcomes were associations between HLA-B*1301 and dapsone-induced cADRs in dapsone-tolerant controls. The outcomes are reported as overall OR. Statistical heterogeneity was assessed using the Q statistic and I2 tests.

Results

From the 3 included studies, there were 111 unique patients with dapsone-induced cADRs (subsequently used in the meta-analysis), 1165 dapsone-tolerant patients, and 3026 healthy controls. The cases included 64 men and 49 women (2 patients were missing from the meta-analysis; 1 each from 2 of the 3 studies); mean age was 39.7 years. An association between HLA-B*1301 and dapsone-induced cADRs was identified (summary OR, 43.0; 95% CI, 24.0-77.2). Subgroup analyses among types of cADRs produced similar findings in DHS (OR, 51.7; 95% CI, 16.9-158.5), dapsone-induced severe cADRs (Stevens-Johnson syndrome and toxic epidermal necrolysis [SJS/TEN] plus drug rash [adverse skin reaction to a drug] along with eosinophilia and systemic symptoms [DRESS]) (OR, 54.0; 95% Cl, 8.0-366.2), dapsone-induced SJS/TEN (OR, 40.5; 95% CI, 2.8-591.0), and dapsone-induced DRESS (OR, 60.8; 95% CI, 7.4-496.2). There was no heterogeneity (I2 = 0%, P = .38).

Conclusions and Relevance

Associations between HLA-B*1301 and dapsone-induced cADRs were found in dapsone-tolerant and healthy control groups. For patient safety, genetic screening for HLA-B*1301 in Asian populations before dapsone therapy is warranted.

Consensus on the treatment of autoimmune bullous dermatoses: dermatitis herpetiformis and linear IgA bullous dermatosis - Brazilian Society of Dermatology

Dermatitis herpetiformis and linear IgA bullous dermatosis are autoimmune diseases that present with pruritic urticarial papules and plaques, with formation of vesicles and blisters of subepidermal location, mediated by IgA antibodies. Mucosal lesions are present only in linear IgA bullous dermatosis. The elaboration of this consensus consisted of a brief presentation of the different aspects of these dermatoses and, above all, of an updated literature review on the various therapeutic options that were discussed and compared with the authors' experience, aiming at the treatment orientation of these diseases in Brazil. Dermatitis herpetiformis is a cutaneous manifestation of celiac disease, and can be controlled with a gluten-free diet and dapsone. On the other hand, linear IgA bullous dermatosis arises spontaneously or is triggered by drugs, and can be controlled with dapsone, but often requires the association of systemic corticosteroids and eventually immunosuppressants.

[Dermatitis herpetiformis]

Dermatitis herpetiformis (DH) is a genetically determined, gluten sensitive autoimmune bullous dermatosis related to celiac disease in which granular, insoluble aggregates in the papillary dermis of epidermal transglutaminase (TG3), immunoglobulin A (IgA), and fibrinogen are present. Detection of the dermal IgA-TG3 immune complex is the gold standard of diagnosis. DH develops in a subpopulation of patients with gluten sensitive enteropathy, characterized by itching, erythematous, excoriated papules showing characteristic distribution over the knees, elbows and buttocks; vesicles are rarely seen. The primary therapy of DH is a strict, lifelong gluten-free diet, and it may be necessary to temporarily give dapsone in case of severe symptoms.

DNA minor groove binding of a well known anti-mycobacterial drug dapsone: A spectroscopic, viscometric and molecular docking study

Dapsone is a sulfone drug mainly used as anti-microbial and anti-inflammatory agent for the treatment of various diseases including leprosy. Recently, its interaction with protein (bovine serum albumin) is evidenced. But, the binding propensity of this anti-mycobacterial drug towards DNA is still unknown. Also, the mode of dapsone-DNA interaction (if any) is still an unknown quantity. In this study, we have taken a thorough attempt to understand these two unknown aspects using various biophysical and in silico molecular docking techniques. Both UV-visible and fluorescence titrimetric studies indicated that dapsone binds to CT-DNA with a binding constant in order of 10⁴ M^-1. Circular dichroism, thermal denaturation and viscosity experiments revealed that dapsone binds to the grooves of CT-DNA. Competitive DNA binding studies clearly indicated the minor groove binding property of this anti-mycobacterial drug. Molecular docking provided detailed information about the formation of hydrogen bonding in the dapsone-DNA complex. This in silico study further revealed that dapsone binds to the AT-rich region of the minor groove of DNA having a relative binding energy of -6.22 kcal mol^-1. Overall, all these findings evolved from this study can be used for better understanding the medicinal importance of dapsone.

Topical, systemic and biologic therapies in hidradenitis suppurativa: pathogenic insights by examining therapeutic mechanisms

Hidradenitis suppurativa (HS) is a chronic inflammatory disease of the skin, manifesting in chronic, recurrent painful pustules, nodules, boils and purulent draining abscesses. Our current understanding of the pathogenesis of the disease is incomplete. This review aims to identify available treatment options in HS and discuss the pharmacological mechanisms through which such agents function. Identifying common pathways may inform our understanding of the pathogenesis of HS as well as identify future therapeutic targets. The pharmacological mechanisms implicated in topical therapies, antibiotic, hormonal, systemic immunomodulatory and biologic therapies for HS are discussed. Significant differences exist between agents and implicated pathways in therapy for mild and severe disease. This is an expression of the possible dichotomy in inflammatory pathways (and treatment responses) in HS. Studies involving monoclonal antibodies provide the greatest insight into what these specific mechanisms may be. Their variable levels of clinical efficacy compared with placebo bolsters the suggestion that differential inflammatory pathways may be involved in different presentations and severity of disease. Nuclear factor kappa B (NF-κB), tumor necrosis factor (TNF)-α and other innate immune mechanisms are strongly represented in treatments which are effective in mild to moderate disease in the absence of scarring or draining fistulae, however complex feed-forward mechanisms in severe disease respond to interleukin (IL)-1 inhibition but are less likely to respond to innate immune inhibition (through NF-κB or TNF-α) alone. It is unclear whether IL-17 inhibition will parallel TNF-α or IL-1 inhibition in effect, however it is plausible that small molecule targets (Janus kinase1 and phosphodiesterase 4) may provide effective new strategies for treatment of HS.