Low-dose dapsone in chronic idiopathic urticaria: preliminary results of an open study

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.

Use of Dapsone in the Treatment of Chronic Idiopathic and Autoimmune Urticaria

Importance

The first-line treatment for patients with chronic spontaneous urticaria (CSU), which is divided into idiopathic and autoimmune subtypes, consists of H1-antihistamines. However, limited evidence guides the treatment of CSU after maximal therapy with antihistamines fails. Two randomized clinical trials suggest that dapsone may be a successful second-line therapy.

Objective

To evaluate the efficacy and safety of dapsone therapy in patients with CSU.

Design, Setting, and Participants

This retrospective medical record review included 79 patients with CSU treated with dapsone who presented to the tertiary care academic medical center at the New York University School of Medicine, New York, New York, from January 1, 2005, through April 15, 2017. Follow-up was completed on February 28, 2018. Data were analyzed from March 1 through May 31, 2018.

Exposures

Treatment with oral dapsone for CSU.

Main Outcomes and Measures

Efficacy of dapsone therapy for CSU was evaluated as improvement, complete response, and remission.

Results

Seventy-nine patients (65% women; mean [SD] age, 49.8 [16.1] years [range, 20-79 years]) were included in the analysis. Forty-five patients had chronic idiopathic urticaria and 34 had chronic autoimmune urticaria. Improvement in CSU was observed in 62 patients (78%) (36 [80%] with idiopathic and 26 [76%] with autoimmune disease) with dapsone. Mean (SD) time to improvement was 1.1 (1.0) months. A complete response was achieved in 29 (47%) of these 62 patients (16 [44%] with idiopathic and 13 [50%] with autoimmune disease). Mean (SD) time to complete response was 5.2 (5.2) months. Dapsone therapy was tapered in 21 patients after a mean (SD) of 2.4 (2.2) months and discontinued in 18. Ten patients experienced remission with no subsequent flares, even after dapsone therapy was discontinued with follow-up of 0.3 to 10.0 months. Sixteen patients experienced mild adverse effects. Two serious adverse effects were reported.

Conclusions and Relevance

Results of this study suggest that dapsone is a useful and well-tolerated second-line therapy for patients with CSU in whom antihistamines and other first-line agents have failed.

Chronic spontaneous urticaria: latest developments in aetiology, diagnosis and therapy

Chronic urticaria is a debilitating disease characterized by itching and hives with or without angioedema lasting for more than 6 weeks. The disease carries a significant emotional and economic burden for the patient and often results in an odyssey between doctors of different specialities. Patients suffering from chronic urticaria are considered more difficult to satisfy, treat and to have a bigger emotional burden than the average patient in dermatology, paediatric and general practice settings. A joint initiative under the Dermatology section of the European Academy of Allergy and Clinical immunology (EAACI), the Global Allergy and Asthma European Network (GA(2)LEN), the European Dermatology Forum (EDF) and the World Allergy Organization (WAO) has resulted in recently published guidelines for the diagnosis, classification and treatment of chronic urticarial: these guidelines are clinically useful and have a high success rate when followed in daily clinical practice. The treatment of choice for chronic urticaria is still nonsedating antihistamines although other treatments are available, with omalizumab (humanized IgG anti IgE antibodies) as the newest therapy. The pathogenesis of urticaria is poorly understood but autoimmunity is considered as one of the major underlying causes for this disease, although other theories exist.

Chronic urticaria: new management options

Chronic urticaria is defined as episodic or daily hives lasting for at least 6 weeks and impairs quality of life. Two main subtypes include chronic idiopathic (spontaneous) urticaria and inducible (physical) urticaria, but some patients have urticarial vasculitis. “Autoimmune chronic urticaria” implies the presence of histamine releasing or mast cell activating autoantibodies to IgE or FcϵRI, the high affinity receptor on mast cells and basophils. In patients not readily controlled with labeled dosages of second generation H₁ receptor antagonists (antihistamines), there is evidence for reduction of urticaria using up to 4 fold increases in labeled dosages. The biologic modifier, omalizumab, helps to reduce lesions of chronic urticaria within 1–2 weeks.

Double-blind placebo-controlled trial of dapsone in antihistamine refractory chronic idiopathic urticaria

BACKGROUND

Management of antihistamine refractory chronic idiopathic urticaria (CIU) has poorly defined therapeutic options.

OBJECTIVE

To evaluate the efficacy of dapsone (4,4'-diaminodiphenylsulfone) in antihistamine refractory CIU compared with placebo.

METHODS

Twenty-two patients with antihistamine refractory CIU were randomly assigned to 100 mg of dapsone daily or placebo for 6 weeks in a 14-week double-blind, placebo-controlled crossover trial. End points were measured from a daily diary that reflected the weekly hive score, the weekly itch score, and a visual analog scale (VAS) score. Secondary to a carryover effect, the first period results were analyzed as a parallel design that compared placebo with dapsone directly by using repeated-measures analysis.

RESULTS

After 6 weeks, the patients in the dapsone arm showed mean improvement over baseline in VAS (2.3 [95% CI, 0.6-4.1], P = .01), urticaria score (-3.5 [95% CI, -6.2 to -0.9], P = .01), and itch score (-4.8 [95% CI, -7.6 to -2.1], P = .001), whereas the placebo arm showed no improvement over baseline for VAS, urticaria, or itch scores. Dapsone showed greater improvement compared with placebo for itch (P = .047) and VAS (P = .04). Of the 22 patients, 3 showed complete resolution of hives and itch with dapsone, whereas 31% and 41% had ≥ 50% resolution of hives and itch, respectively. No serious adverse effects were observed with dapsone.

CONCLUSION

To our knowledge, this is the first double-blind, placebo controlled study of dapsone in CIU and indicates that dapsone has efficacy in patients with antihistamine refractory CIU.

Dapsone in dermatology and beyond

Dapsone (4,4′-diaminodiphenylsulfone) is an aniline derivative belonging to the group of synthetic sulfones. In 1937 against the background of sulfonamide era the microbial activity of dapsone has been discovered. Shortly thereafter, the use of dapsone to treat non-pathogen-caused diseases revealed alternate antiinflammatory mechanisms that initially were elucidated by inflammatory animal models. Thus, dapsone clearly has dual functions of both: antimicrobial/antiprotozoal effects and anti-inflammatory features similarly to non-steroidal anti-inflammatory drugs. The latter capabilities primarily were used in treating chronic inflammatory disorders. Dapsone has been investigated predominantly by in vitro methods aiming to get more insights into the effect of dapsone to inflammatory effector cells, cytokines, and/or mediators, such as cellular toxic oxygen metabolism, myoloperoxidase-/halogenid system, adhesion molecules, chemotaxis, membrane-associated phospholipids, prostaglandins, leukotrienes, interleukin-8, tumor necrosis factor α, lymphocyte functions, and tumor growth. Moreover, attention has been paid to mechanisms by which dapsone mediates effects in more complex settings like impact of lifespan, stroke, glioblastoma, or as anticonvulsive agent. Additionally, there are some dermatological investigations in human being using dapsone and its metabolites (e.g., leukotriene B₄-induced chemotaxis, ultraviolet-induced erythema). It could be established that dapsone metabolites by their own have anti-inflammatory properties. Pharmacology and mechanisms of action are determining factors for clinical use of dapsone chiefly in neutrophilic and/or eosinophilic dermatoses and in chronic disorders outside the field of dermatology. The steroid-sparing effect of dapsone is useful for numerous clinical entities. Future avenues of investigations will provide more information on this fascinating and essential agent.

Diagnosis and treatment of urticaria and angioedema: a worldwide perspective

: Urticaria and angioedema are common clinical conditions representing a major concern for physicians and patients alike. The World Allergy Organization (WAO), recognizing the importance of these diseases, has contributed to previous guidelines for the diagnosis and management of urticaria. The Scientific and Clinical Issues Council of WAO proposed the development of this global Position Paper to further enhance the clinical management of these disorders through the participation of renowned experts from all WAO regions of the world. Sections on definition and classification, prevalence, etiology and pathogenesis, diagnosis, treatment, and prognosis are based on the best scientific evidence presently available. Additional sections devoted to urticaria and angioedema in children and pregnant women, quality of life and patient-reported outcomes, and physical urticarias have been incorporated into this document. It is expected that this article will supplement recent international guidelines with the contribution of an expert panel designated by the WAO, increasing awareness of the importance of urticaria and angioedema in medical practice and will become a useful source of information for optimum patient management worldwide.

[Therapeutic alternatives for antihistamine-refractory urticaria]

Patients with chronic spontaneous urticaria, the most frequent non-acute form of urticaria, generally exhibit a clinical picture of persistent disease, a high degree of disease activity, considerable impairment of quality of life, and poor response to treatment. More than half of the patients continue to develop symptoms despite standard therapy with non-sedating antihistamines. In these cases, the antihistamine dose should be increased (up to four times the daily dose). If this approach also does not result in symptom control, the high-dose antihistamine should be combined with a leukotriene antagonist and if necessary an H2 blocker. If the patient does not respond to this combination therapy, cyclosporin A, dapsone, or omalizumab should be administered.

Management of difficult urticaria

Chronic urticaria, a major health problem causing patient's distress, induces often physicians' dilemma while dealing with its etiology, investigations and management. Clinical approach of such cases should include apart from clinical history and physical examination laboratory investigations like routine blood test, thyroid profile, etc. as well as sometimes special test like autologous serum skin test. Management includes reassurance, avoidance of precipitating factors, treatment of underlying disorders, and non-pharmacological approach along with pharmacotherapy. First line drug therapy comprises non-sedative and sedative antihistamines, second line doxepin, nifedipine, leukotriene-inhibitors, sulfasalazine, etc. and third line cyclosporine, dapsone, colchicin, etc.

Immunomodulatory approaches to the management of chronic urticaria: an immune-mediated inflammatory disease

Although commonly encountered in clinical practice, chronic urticaria (CU) remains difficult to treat. In contrast to acute urticaria, neither exogenous triggers nor specific immunoglobulin E are identified in most chronic cases. A body of evidence suggests that CU is represented within the spectrum of immune-mediated inflammatory diseases (IMID). Our understanding of the CU disease pathogenesis now recognizes a role for T cells, B cells, and autoantibodies, and intrinsic abnormalities of histamine-releasing effector cells, thus providing new targets of intervention beyond the current mainstay of often inadequate symptomatic treatment directed against histamine receptors and steroids, with their attendant morbidities. Agents previously used to treat other autoimmune and inflammatory diseases have demonstrated efficacy in CU. Newer biologic and nonbiologic immunomodulatory agents approved for other indications and in clinical development provide potential options for this often severe disease.