Alitretinoin abrogates innate inflammation in palmoplantar pustular psoriasis

An update on therapeutic options for palmoplantar pustulosis: a narrative review and expert recommendations

INTRODUCTION

Palmoplantar pustulosis (PPP) is a chronic inflammatory skin disease belonging to the localized form of pustular psoriasis. It is characterized by sterile pustule formation in palms and soles and a recurrent disease course. Although we have many treatments for PPP, there is no authoritative guidance.

AREAS COVERED

A thorough search of PubMed was conducted to identify studies in PPP from 1973 onwards, with additional references to specific articles. Any treatment methods were outcomes of interest, including topical treatment, systemic treatment, biologics, other targeted treatments, phototherapy, and tonsillectomy.

EXPERT OPINION

Topical corticosteroids are suggested as first-line therapy. Oral acitretin has become the most applied systemic retinoid recommended in PPP without joint involvement. For patients with arthritis, immunosuppressants like cyclosporin A and methotrexate are more recommended. UVA1, NB-UVB, and 308-nm excimer laser are effective phototherapy options. The combinations of topical or systemic agents and phototherapy may enhance the efficacy, particularly in recalcitrant cases. Secukinumab, ustekinumab, and apremilast are the most investigated targeted therapies. However, heterogeneous reported outcomes in clinical trials provided low-to-moderate quality evidence of their efficacy. Future studies are required to address these evidence gaps. We suggest managing PPP based on the acute phase, maintenance phase, and comorbidities.

CD303 (BDCA-2) - a potential novel target for therapy in hematologic malignancies

Plasmacytoid dendritic cells (pDCs) serve as immunoregulatory antigen-presenting cells that play a role in various inflammatory, viral, and malignant conditions. Malignant proliferation of pDCs is implicated in the pathogenesis of certain hematologic cancers, specifically blastic plasmacytoid dendritic cell neoplasm (BPDCN) and acute myelogenous leukemia with clonal expansion of pDC (pDC-AML). In recent years, BPDCN and pDC-AML have been successfully treated with targeted therapy of pDC-specific surface marker, CD123. However, relapsed and refractory BPDCN remains an elusive cancer, with limited therapeutic options. CD303 is another specific surface marker of human pDCs, centrally involved in antigen presentation and immune tolerance. Monoclonal antibodies directed against CD303 have been studied in preclinical models and have achieved disease control in patients with cutaneous lupus erythematosus. We performed a comprehensive review of benign and malignant disorders in which CD303 have been studied, as there may be a potential future CD303-directed therapy for many of these conditions.

2020 Korean Consensus Guidelines for Diagnosis and Treatment of Chronic Hand Eczema

Background

Hand eczema refers to eczema located on the hands, regardless of its etiology or morphology. Despite its high prevalence and significant impact on patients' quality of life, treatment is frequently challenging because of its heterogeneity, chronic and recurrent course, and lack of well-organized randomized controlled trials of the various treatment options.

Objective

These consensus guidelines aim to provide evidence-based recommendations on the diagnosis and management of hand eczema to improve patient care by helping physicians make more efficient and transparent decisions.

Methods

A modified Delphi method, comprising two rounds of email questionnaires with face-to-face meetings in between, was adopted for the consensus process that took place between February and September 2020. Forty experts in the field of skin allergy and contact dermatitis were invited to participate in the expert panel.

Results

Consensus was reached for the domains of classification, diagnostic evaluation, and treatment; and a therapeutic ladder to manage chronic hand eczema was developed.

Conclusion

These are the first consensus guidelines for chronic hand eczema in the Asian population, which will help standardize care and assist clinical decision-making in the diagnosis and treatment of chronic hand eczema.

A multicentre open-label study of apremilast in palmoplantar pustulosis (APLANTUS)

BACKGROUND

Palmoplantar pustulosis (PPP) is a chronic skin disease with painful erythematous scaly or crusty lesions and pustules on the palms and soles. Apremilast is a phosphodiesterase 4 inhibitor that has proven effective in the therapy of psoriasis, psoriatic arthritis and in oral ulcers associated with Behcet's disease.

OBJECTIVE

To explore the efficacy of apremilast in PPP.

METHODS

APLANTUS was a phase 2 single-arm multicentre study of apremilast in 21 subjects with moderate-to-severe PPP. Primary endpoint was the per cent change of the Palmoplantar Pustulosis Psoriasis Area and Severity Index (PPPASI) at week 20 compared to baseline.

RESULTS

20 weeks of oral treatment with apremilast in patients with moderate-to-severe PPP resulted in a significant decrease of the PPPASI with a median reduction of 57.1% (p < 0.001), and 61.9% of patients achieved at least a 50% improvement of the PPPASI relative to baseline. The total number of pustules per patient decreased significantly relative to baseline with 76.2% of patients achieving at least a 50% reduction in total pustules count at week 20. Improvement of PPP was also apparent in a significant decrease of the dermatologic life quality index (DLQI). The median DLQI score dropped from 8.5 at baseline to 2.0 at week 20 (p = 0.030). Apremilast was generally well tolerated, and no serious adverse events occurred.

CONCLUSIONS

Patients with PPP treated with apremilast showed benefit both in objective and subjective disease parameters. Apremilast should be investigated further in this difficult-to-treat skin condition. EudraCT number: 2016-005122-11.

Similarity and difference between palmoplantar pustulosis and pustular psoriasis

Palmoplantar pustulosis is a chronic inflammatory disorder characterized by sterile pustules predominantly involving the palms and soles. Palmoplantar pustulosis has many similar aspects to psoriasis, either plaque and pustular type, namely familial occurrence between palmoplantar pustulosis and psoriasis, the appearance of the Köbner phenomenon, joint involvement, and nail involvement. Pustular psoriasis is classified into generalized and localized types, and there are a number of papers regarding palmoplantar pustulosis as an acral variant of localized pustular psoriasis. Many Japanese dermatologists consider palmoplantar pustulosis to be a distinct entity from pustular psoriasis, and the coexistence of palmoplantar pustulosis and psoriasis is rare. However, outside Japan, palmoplantar pustulosis is often considered to be palmoplantar psoriasis or palmoplantar pustular psoriasis, and extra-palmoplantar lesions are also considered to be psoriasis. The purpose of the current review is to compare the similarities and differences between palmoplantar pustulosis and generalized/localized pustular psoriasis. Japanese patients with palmoplantar pustulosis have a close relationship with focal infection, and the associated bone-joint manifestation exclusively involves the anterior chest wall. Furthermore, pediatric occurrence of palmoplantar pustulosis is extremely rare, and difference of genetic background between palmoplantar pustulosis and psoriasis has also been reported. Treatment of focal infection often results in dramatic effects on both cutaneous lesions and joint pain of palmoplantar pustulosis. Those findings suggest that palmoplantar pustulosis should be separately considered from either palmoplantar psoriasis or palmoplantar pustular psoriasis. The clinicopathological features and therapeutic approach of both diseases are discussed.

Illuminating the Role of Vitamin A in Skin Innate Immunity and the Skin Microbiome: A Narrative Review

Vitamin A is a fat-soluble vitamin that plays an important role in skin immunity. Deficiencies in Vitamin A have been linked to impaired immune response and increased susceptibility to skin infections and inflammatory skin disease. This narrative review summarizes recent primary evidence that elucidates the role of vitamin A and its derivatives on innate immune regulators through mechanisms that promote skin immunity and sustain the skin microbiome.

Oral Alitretinoin for Patients with Refractory Prurigo

Background: prurigo is a chronic skin disorder associated with a history of chronic pruritus. The pathogenesis of prurigo is largely unknown and the treatment of prurigo is unsatisfactory and challenging. Conventional systemic treatments may be beneficial; however, their possible side effects and possible transient efficacy is still a problem. We aimed to present the clinical course and effect of treatment with alitretinoin on patients with prurigo nodularis initially treated with conventional treatments like oral antihistamine, cyclosporine, and phototherapy. Methods: all the patients had prurigo nodularis refractory to conventional treatment. Their medical records included demographic features, past medical history, duration of disease, and treatment modalities; and the clinical courses of the patients were reviewed for this retrospective study. We evaluated patient pruritus and skin lesions for the duration. Results: we present reports involving 10 patients with refractory prurigo. All the patients in our cases were treated with oral alitretinoin after previous treatments and reported the improvement of skin lesions and pruritus within 2 weeks to 3 months. Conclusions: we suggest that oral alitretinoin may be an effective and well tolerated treatment option for patients with intractable prurigo. Further clinical studies are warranted to confirm the long-lasting efficacy and safety of alitretinoin for treating patients with prurigo.

Palmoplantar Pustulosis: Recent Advances in Etiopathogenesis and Emerging Treatments

Palmoplantar pustulosis (PPP) is a chronic, recurrent skin disease belonging to the spectrum of psoriasis. It is characterized by an eruption of sterile pustules on the palms and soles. Recent studies in PPP have focused on genetic differences between pustular phenotypes and the role of the innate immunological system and the microbiome in the etiopathogenesis of the disease. Mutations in IL36RN (a major predisposing factor for generalized pustular psoriasis) were found in selected patients with PPP and were associated with earlier disease onset. Studies have shown that the interleukin (IL)-17 and IL-36 pathways might be involved in the pathogenesis of PPP. A microbiome has been demonstrated in the vesicopustules of PPP, and an abundance of Staphylococcus appears to be increased by smoking. Improved understanding of the underlying etiopathogenesis of PPP has led to advances in treatment options, and targeted therapies for PPP have been evaluated or are under evaluation against more than 12 molecules in ongoing clinical trials. These targets include CXCR2 (IL-8 receptor type B), granulocyte colony-stimulating factor receptor, IL-1 receptor, IL-8, IL-12, IL-23, IL-17A, IL-17 receptor, IL-36 receptor, phosphodiesterase-4, and tumor necrosis factor-α.

Safe and effective use of alitretinoin in children with recalcitrant hand eczema and other dermatoses - a retrospective analysis

BACKGROUND

Alitretinoin is a systemic retinoid licensed for use in adult patients suffering from chronic hand eczema recalcitrant to potent topical steroids. Experience with its use in childhood is lacking.

OBJECTIVES

To report on the efficacy and safety of alitretinoin treatment in a cohort of children and adolescents with chronic hand eczema (CHE) and other inflammatory skin diseases.

METHODS

We performed a retrospective chart review of all consecutive patients under the age of 18 years treated with alitretinoin at our paediatric skin centre. Physician's Global Assessment (PGA) was used as the primary outcome measure.

RESULTS

Thirteen children (9 girls and 4 boys) were enrolled in this study. The median age at start of treatment with alitretinoin was 11.5 years (range 5.8-15.8 years). Nine children were diagnosed with CHE, two with severe atopic dermatitis (AD), and two with inherited ichthyosis [netherton syndrome (NS), autosomal recessive congenital ichthyosis (ARCI)]. Moderate to excellent response (PGA decrease of ≥1 point) was observed in 7 (78%) of the nine patients with CHE, one of the two patients with extensive AD and in the one patient with ARCI. In the remaining four subjects, no convincing effect was documented. Tolerability was overall very good. The most common adverse event was headache in 10 patients (77%) during the initiation of treatment, leading to interruption of therapy in one subject.

CONCLUSIONS

Alitretinoin seems to be highly effective and safe for the treatment of paediatric CHE and should thus be considered in children with refractory disease under topical therapy. Larger studies are required to corroborate these findings.

Efficacy and Safety of Oral Alitretinoin in Hand Eczema and Palmoplantar Pustulosis in Korean Patients

Background

Previous studies have demonstrated efficacy and safety of oral alitretinoin in hand eczema (HE) whereas in palmoplantar pustulosis (PPP), which can be difficult to distinguish from HE, efficacy of alitretinoin is still controversial.

Objective

This study aimed to investigate the efficacy and safety of oral alitretinoin in HE and PPP and factors that affect the response of these disorders to alitretinoin.

Methods

We retrospectively analyzed Korean adult patients with moderate-to-severe HE and PPP treated with oral alitretinoin, 46 patients for efficacy assessment and 55 patients for safety assessment.

Results

Among 46 patients who were treated with alitretinoin for at least 1 month, 29 patients (61.1% in HE and 40.0% in PPP) showed response to alitretinoin in the median 14 weeks after treatment. Hyperkeratotic HE showed higher response rate than either vesicular HE or PPP (p=0.026 and p=0.026, respectively). However, PPP with hyperkeratotic features showed as much response as hyperkeratotic HE (p=0.554). When responders and non-responders in total patients were compared, morphology, not diagnosis or initial severity, was the only significantly different factor between the two groups. After alitretinoin discontinuation in responders, relapse rate was 63.6% (7/11) and median time to relapse was 150 days (range, 76~730 days). Adverse events occurred in 47.3% (26/55); however, there were no serious adverse events.

Conclusion

In HE or PPP, lesions with hyperkeratotic morphology can be predicted to respond well to alitretinoin regardless of diagnosis.

Drug-induced pyoderma gangrenosum: a model to understand the pathogenesis of pyoderma gangrenosum

Pyoderma gangrenosum (PG) is a rare autoinflammatory condition in which the alteration of neutrophil function and the innate immune response play key roles in its pathogenesis. Cases of PG have been reported in patients being treated with certain medications, which may help us to understand some of the possible pathways involved in the aetiology of PG. The aim of this review is to review the cases of PG triggered by certain drugs and try to thoroughly understand the pathogenesis of the disease. To accomplish this, a PubMed search was completed using the following words: pyoderma gangrenosum, neutrophilic dermatosis, pathophysiology, drug-induced pyoderma gangrenosum. In total, we found 43 cases of drug-induced PG. Most of them were caused by colony-stimulating factors and small-molecule tyrosine kinase inhibitors. We propose that drugs induce PG through various mechanisms such as dysfunctional neutrophil migration and function, dysregulated inflammatory response, promotion of keratinocyte apoptosis and alteration of epigenetic mechanisms. PG is a rare condition with complex pathophysiology and drug-induced cases are even more scarce; this is the main limitation of this review. Understanding the possible mechanisms of drug-induced PG, via abnormal neutrophil migration and function, abnormal inflammation, keratinocyte apoptosis and alteration of epigenetic mechanisms would help to better understand the pathogenesis of PG and ultimately to optimize targeted therapy.

Palmoplantar psoriasis

Palmoplantar psoriasis refers to a localized psoriasis variant. The disease can be associated with many clinical forms, including predominantly pustular lesions to thick scaly, hyperkeratotic plaques, or an overlapping of both of them. Palmoplantar psoriasis accounts for 3-4% of all psoriasis cases in most studies. Although it is localized only on the palms and the soles, the fissures, the hardening of the tissue, and hyperkeratosis affect daily routine activities. Taking the body surface area as a measure of severity can sometimes be misleading. In clinical practice, the level of functional impairment should be taken into account rather than relying on traditional instruments to evaluate the severity. Palmoplantar psoriasis is usually managed with topical therapy as a first step. Systemic therapy is needed when the topicals fail or when the disease becomes more severe. Sometimes, biologic agents are required for adequate maintenance of clinical response.

Palmoplantar Psoriasis and Palmoplantar Pustulosis: Current Treatment and Future Prospects

Palmoplantar psoriasis and palmoplantar pustulosis are chronic skin diseases with a large impact on patient quality of life. They are frequently refractory to treatment, being generally described as a therapeutic challenge. This article aims to review the definitions of palmoplantar psoriasis and palmoplantar pustulosis, highlighting the similarities and differences in terms of epidemiology, clinical presentation, genetics, histopathology, and pathogenesis, as well as treatment options for both entities. Classical management of mild to moderate palmoplantar pustulosis and palmoplantar psoriasis relies on use of potent topical corticosteroids, phototherapy, and/or acitretin. Nevertheless, these drugs have proven to be insufficient in long-term control of extensive disease. Biologic therapy-namely, anti-interleukin-17 agents and phosphodiesterase type 4 inhibitors-has recently shown promising results in the treatment of palmoplantar psoriasis. Knowledge of the pathophysiologic pathways of both entities is of utmost importance and may, in the future, allow development of molecularly targeted therapeutics.

Alitretinoin in Dermatology-An Update

Alitretinoin is a pan retinoic acid agonist. It was initially used as 0.1% gel in the management of localized Kaposi's sarcoma. At present, the use of systemic alitretinoin has proved extremely efficacious in the management of recalcitrant chronic hand eczema. Furthermore, there have been other retinoid responsive dermatosis that have demonstrated remission post usage of systemic alitretinoin. With a better toxicity profile, compared to the other systemic retinoids, alitretinoin could be considered a valuable treatment option in the near future for the treatment of these dermatologic disorders.

Alitretinoin for the treatment of severe chronic hand eczema

Chronic hand eczema is a common and often debilitating condition. Alitretinoin, a 9-cis-retinoic acid and pan-retinoic acid agonist, is a new and effective systemic treatment for chronic hand eczema, which provides another treatment option. A "clear" or "almost clear" response can be achieved in up to half of patients within a 24-week course of treatment. Even higher rates of remission can be obtained with a longer duration of treatment. Alitretinoin has a favorable overall profile of adverse effects; however, female patients who are at risk of becoming pregnant should follow a strict pregnancy-prevention program due to the teratogenic effects of this drug.

[Off-label use of alitretinoin]

Oral alitretinoin (9-cis retinoic acid) is an endogenous retinoid related to vitamin A. Studies have shown that oral alitretinoin is effective and well-tolerated in the treatment of severe chronic hand eczema, so that it is approved for this indication. This review summarizes new studies and clinical experience on the off-label use of alitretinoin.