Interleukin 23-Helper T Cell 17 Axis as a Treatment Target for Pityriasis Rubra Pilaris

Role of IL-23 inhibitors including risankizumab and guselkumab in the treatment of pityriasis rubra pilaris

Pityriasis rubra pilaris (PRP) is a rare and chronic inflammatory dermatologic condition characterized by hyperkeratotic salmon-colored plaques and palmoplantar keratoderma. Traditional therapeutic modalities have shown limited efficacy and often entail potential adverse effects, highlighting the need for alternative treatment options. Our review aims to summarize the current evidence on the off-label use of IL-23 inhibitors, risankizumab and guselkumab, in the treatment of PRP. These biologic agents have been approved for psoriasis, and their potential role in managing PRP has recently garnered interest. We conducted a comprehensive literature search on PubMed and Scopus databases, identifying relevant studies published in English up to June 2023 following PRISMA guidelines. A total of 10 studies were selected for data extraction and review. Results from the selected studies demonstrated encouraging outcomes with both risankizumab and guselkumab in managing PRP. Among 11 patients treated with risankizumab, 10 showed notable improvements in various disease manifestations, including pruritus, erythema, and affected body surface area. DLQI scores and BSA percentages reported a significant improvement before and after risankizumab treatment (p = 0.0322; p = 0.0216). However, two cases also reported symptom aggravation or even disease worsening. Patients treated with guselkumab exhibited ultimate improvement in all five cases, with complete clearance in three out of five cases. DLQI and BSA percentages also reported significant improvement with treatment with guselkumab (p = 0.0172; p < 0.0001). While most cases demonstrated positive outcomes, there were isolated instances of worsening symptoms, emphasizing the need for caution and further investigation. Further research with larger sample sizes and longer follow-up periods is necessary to establish the efficacy, optimal dosing, and long-term safety of risankizumab and guselkumab in treating PRP. Overall, we provide valuable insights into the potential use of IL-23 inhibitors, risankizumab, and guselkumab, as promising treatment options for PRP. These biologics have shown efficacy in improving symptoms in treatment-resistant cases, offering new avenues for clinicians to explore in the treatment of PRP.

IL-17 in wound repair: bridging acute and chronic responses

Chronic wounds, resulting from persistent inflammation, can trigger a cascade of detrimental effects including exacerbating inflammatory cytokines, compromised blood circulation at the wound site, elevation of white blood cell count, increased reactive oxygen species, and the potential risk of bacterial infection. The interleukin-17 (IL-17) signaling pathway, which plays a crucial role in regulating immune responses, has been identified as a promising target for treating inflammatory skin diseases. This review aims to delve deeper into the potential pathological role and molecular mechanisms of the IL-17 family and its pathways in wound repair. The intricate interactions between IL-17 and other cytokines will be discussed in detail, along with the activation of various signaling pathways, to provide a comprehensive understanding of IL-17's involvement in chronic wound inflammation and repair.

Biologics for Treatment of Pityriasis Rubra Pilaris: A Literature Review

OBJECTIVE

To describe the published efficacy and adverse event rates associated with existing biologics for the treatment of pityriasis rubra pilaris (PRP).

DATA SOURCES

A literature review using the PubMed database (January 1990-July 2023) was conducted. Multiple search combinations were conducted using "pityriasis rubra pilaris" and various biologics as keywords to identify relevant articles.

STUDY SELECTION AND DATA EXTRACTION

Inclusion criteria included all study types that were published within the past 30 years in English and mentioned at least one biologic and PRP. A preliminary search yielded a total of 499 results. After screening using inclusion and exclusion criteria, 77 relevant articles (69 case reports, 5 case series, 2 clinical trials, and 1 retrospective analysis) were analyzed.

DATA SYNTHESIS

TNF-α inhibitors have been evaluated and are effective in treating PRP. However, recent treatment with anti-interleukin (IL)-17 and anti-IL-23 therapies such as ustekinumab, secukinumab, and ixekizumab are emerging as new treatment options with a mean improvement in PRP Area and Severity Index scores, change in severity of erythema, scaling, and thickness of PRP lesions. From initial clinical trials, secukinumab and ixekizumab are promising treatment options for achieving remission.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review compares the efficacy for numerous biologics and a discussion to guide clinicians on benefits and risks in choosing a biologic for PRP patients.

CONCLUSIONS

Biologics may be a favourable treatment option leading to greater patient adherence due to reduced dosing frequencies, improvement in quality of life, and reduction in frequency and severity of flares.

Immune cells in skin inflammation, wound healing, and skin cancer

Given the self-evident importance of cutaneous immunity in the maintenance of body-surface homeostasis, disturbance of the steady-state skin is inextricably intertwined with dysfunction in cutaneous immunity. It is often overlooked by people that skin, well-known as a solid physical barrier, is also a strong immunological barrier, considering the abundant presence of immune cells including lymphocytes, granulocytes, dendritic cells, and macrophages. What's more, humoral immune components including cytokines, immunoglobulins, and antimicrobial peptides are also rich in the skin. This review centers on skin inflammation (acute and chronic, infection and aseptic inflammation), wound healing, and skin cancer to elucidate the elaborate network of immune cells in skin diseases.

Rapid response of erythrodermic pityriasis rubra pilaris to tildrakizumab

The cases of two patients with erythrodermic pityriasis rubra pilaris that showed a rapid and virtually complete response to tildrakizumab are presented. Treatment of pityriasis rubra pilaris remains challenging and there is very little evidence about use of interleukin-23 blockers in this condition. These cases may contribute to extending the available therapeutic options, especially when a fast clearance of the lesions is needed.

Case report: Area of focus of management of severe pityriasis rubra pilaris by dose optimization of adalimumab biosimilar in combination with acitretin and montelukast

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disorder characterized by hyperkeratotic follicular papules, orange-red scaling plaques with islands of sparing and palmoplantar keratoderma. While spontaneous resolution occurs in some cases, treatment can be challenging for others. The use of biologics in PRP management has gained attention in recent studies, although their high costs and potential side effects present limitations. We present a case of a 71-year-old patient with treatment-resistant PRP who showed significant improvement through optimized adalimumab treatment. Considering the emerging role of phospholipase A2 in PRP pathogenesis, montelukast was added, further enhancing the therapeutic response. By maintaining montelukast and prolonging the adalimumab interval to 3 and 4 weeks, effective dose optimization was achieved without PRP relapse. This case report highlights the potential for adalimumab dose optimization by shortening the initial treatment interval for increased effectiveness and lengthening the interval during the maintenance phase to conserve medication doses. Montelukast appears to assist in sustaining clinical outcomes during interval prolongation, necessitating further investigation through additional studies.

Successful Treatment of Pityriasis Rubra Pilaris with Risankizumab in Children

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disease that affects men and women of all ages, including children. PRP is characterized by follicular and palmoplantar hyperkeratosis and salmon-colored scaling plaques. The exact pathogenesis of PRP is still unknown; most PRP cases are acquired, but some cases may show a familial occurrence, often associated with a mutation in the CARD14 gene. Due to the rarity of PRP, treatment recommendations are based mainly on case reports, small case series and expert opinions and still represent a major therapeutic challenge, especially in children. A growing number of reports on treatment with biologicals, particularly anti-TNFα, has been published. However, an involvement of the IL-23/Th17 axis in both psoriasis and PRP pathogenesis may suggest that this pathway may be a potential therapeutic target. Here, we present three pediatric patients with PRP successfully treated with risankizumab. All patients exhibited a severe course of PRP and lack of response to conventional therapy, including acitretin, cyclosporine and phototherapy. A single dose of 75 mg risankizumab resulted in almost complete clearance of skin lesions in case 1 and 2 at week 4. In patient 3, clear skin was achieved after the second administration of risankizumab (150 mg). All patients continue the treatment with risankizumab, and no adverse effects have been reported up to the present time. Our study demonstrates that risankizumab, an IL-23 blocker, shows good efficacy and safety among pediatric patients with PRP.

IL-22 as a target for therapeutic intervention: Current knowledge on its role in various diseases

IL-22 has emerged as a crucial cytokine mediating protective response against pathogens and tissue regeneration. Dysregulated production of IL-22 has been shown to play a pivotal role in the pathogenesis of various diseases like malignant tumours, viral, cardiovascular, allergic and autoimmune disorders. Interleukin 22 belongs to IFN-IL-10 cytokine family. It is a major proinflammatory cytokine secreted by activated Th1 cells (Th22), though can also be secreted by many other immune cells like group 3 innate lymphocytes, γδ T cells, NK cells, NK T cells, and mucosal associated invariant T cells. Th22 cells exclusively release IL-22 but not IL-17 or IFN-γ (as Th1 cells releases IFN-γ along with IL-22 and Th17 cells releases IL-17 along with IL-22) and also express aryl hydrocarbon receptor as the key transcription factor. Th22 cells also exhibit expression of chemokine receptor CCR6 and skin-homing receptors CCR4 and CCR10 indicating the involvement of this subset in bolstering epithelial barrier immunity and promoting secretion of antimicrobial peptides (AMPs) from intestinal epithelial cells. The function of IL-22 is modulated by IL-22 binding protein (binds to IL-22 and inhibits it binding to its cell surface receptor); which serves as a competitor for IL-22R1 chain of IL-22 receptor. The pathogenic and protective nature of the Th22 cells is modulated both by the site of infected tissue and the type of disease pathology. This review aims to discuss key features of IL-22 biology, comparisons between IL and 22 and IFN-γ and its role as a potential immune therapy target in different maladies.

Treatment Options for Juvenile Pityriasis Rubra Pilaris

Pityriasis rubra pilaris represents a group of familial and acquired disorders of cornification that affect both adult and pediatric patients. Treatment options are difficult to assess through clinical trials, given the rarity of the disorder and its tendency for spontaneous remission. Case reports and case series are therefore the primary means of assessment. Because of the heterogeneity of the disease, there is no universal approach to treatment, and multiple agents may need to be trialed to achieve disease control. At present, topicals are used for most pediatric patients, though monotherapy with topicals is only effective for less severe disease. Despite concerns over their side-effect profiles, oral retinoids are generally accepted as a first-line systemic therapy. However, interleukin-17 inhibitors and ustekinumab, an interleukin-12 and interleukin-23 inhibitor, may soon become first-line systemic treatment as well, given their efficacy and relative safety in trials thus far. Ustekinumab, in particular, is emerging as a first-line agent for patients with pityriasis rubra pilaris with CARD14 gene variations. When these therapies fail, second-line and adjunctive therapies to consider include tumor necrosis factor-alpha inhibitors, methotrexate, and phototherapy. However, further investigation is necessary to assess the safety and efficacy of many of these agents in juvenile pityriasis rubra pilaris.

Pityriasis rubra pilaris partially responsive to treatment with upadacitinib: A case report

Pityriasis rubra pilaris is a rare inflammatory dermatosis characterized by orange-red confluent plaques, hyperkeratotic follicular papules, palmoplantar keratoderma, and, in some cases, erythroderma. The etiology of pityriasis rubra pilaris is unclear. This condition is often treated with oral retinoids and topical corticosteroids, and more recently, biological agents have become the mainstay of treatment. However, there is a paucity of high-quality evidence on the safety and effectiveness of these agents, and the disease often remains refractory to therapy. Herein, we present a case of pityriasis rubra pilaris with a favorable response to treatment with upadacitinib, a Janus kinase inhibitor, which has not been previously reported in the literature for the management of this condition.

Anti-interleukin-17A for pityriasis rubra pilaris: catching the psoriasis biologic wave

Linked Article: Boudreaux et al. Br J Dermatol 2022; 187:650–658.

Secukinumab for the treatment of adult-onset pityriasis rubra pilaris: a single-arm clinical trial with transcriptomic analysis

BACKGROUND

The pathogenesis of pityriasis rubra pilaris (PRP) is not completely understood, but interleukin (IL)-17 has been shown to play a critical role. There are no reliable immunomodulatory agents to treat PRP. We conducted an open-label, single-arm clinical trial of secukinumab, a monoclonal antibody that inhibits IL-17A, for the treatment of PRP.

OBJECTIVES

To evaluate the clinical efficacy of secukinumab and define the transcriptomic landscape of PRP and its response to IL-17A blockade.

METHODS

Twelve patients with PRP were recruited for an open-label trial of secukinumab. Patients received a 24-week course of secukinumab. The primary endpoint was a ≥ 75% reduction in Psoriasis Area and Severity Index (PASI 75) from baseline to week 28. Secondary endpoints included PASI 90, change in Physician's Global Assessment (PGA), and change in Dermatology Life Quality Index (DLQI). RNA sequencing was performed on lesional and nonlesional skin biopsies obtained at baseline and week 2. Sample groups were compared to identify differential gene expression and pathway enrichment. This trial was registered with ClinicalTrials.gov: 'Cosentyx (secukinumab) for the treatment of adult onset pityriasis rubra pilaris' - NCT03342573.

RESULTS

At week 28, six of 11 patients (55%) achieved PASI 75, and three patients (27%) achieved PASI 90. PGA (P = 0.008) and DLQI scores (P = 0.010) showed significant improvement with treatment. No serious treatment-related adverse events were encountered. Treatment with secukinumab normalized transcriptional differences between lesional and nonlesional skin. Transcriptomic data from nonresponsive patients suggest that overactivity of innate immune pathways may be driving resistance to secukinumab.

CONCLUSIONS

Secukinumab appears to be an effective treatment for PRP and warrants further investigation. PRP is a transcriptionally heterogeneous disease, reflecting its variable response to therapy. Agents targeting other IL-17 isoforms and innate immune mediators should be considered for future clinical trials. What is already known about this topic? The pathogenesis of pityriasis rubra pilaris is incompletely understood. Successful treatment has been reported with a variety of immunomodulatory agents, but disease is often refractory to therapy. Interleukin (IL)-17 is thought to drive keratinocyte proliferation and vascular dysfunction in this disease. A previous trial demonstrated efficacy of the anti-IL-17A drug ixekizumab for pityriasis rubra pilaris. What does this study add? Herein we describe the findings of a clinical trial of secukinumab, an anti-IL-17A monoclonal antibody, for the treatment of pityriasis rubra pilaris. Secukinumab was effective in treating pityriasis rubra pilaris. Our transcriptomic data give new insight into the expressional changes that occur in response to secukinumab and suggest mechanisms of treatment resistance.

The Role of T Helper 22 Cells in Dermatological Disorders

T helper 22 (Th22) cells are a newly identified subset of CD4+ T cells that secrete the effector cytokine interleukin 22 (IL-22) upon specific antigen stimulation, barely with IFN-γ or IL-17. Increasing studies have demonstrated that Th22 cells and IL-22 play essential roles in skin barrier defense and skin disease pathogenesis since the IL-22 receptor is widely expressed in the skin, especially in keratinocytes. Herein, we reviewed the characterization, differentiation, and biological activities of Th22 cells and elucidated their roles in skin health and disease. We mainly focused on the intricate crosstalk between Th22 cells and keratinocytes and provided potential therapeutic strategies targeting the Th22/IL-22 signaling pathway.

Beyond plaque psoriasis - pathogenesis and treatment of other psoriasis phenotypes

PURPOSE OF REVIEW

Psoriasis vulgaris is the commonest presentation of psoriatic disease, but morphologic variants such as pustular psoriasis (PP) and a closely related disease, pityriasis rubra pilaris (PRP), have been known for a long time, have been associated with rheumatologic manifestations indistinguishable from psoriatic arthritis (PsA) that may go unrecognized, and often represent a therapeutic conundrum. There is recent evidence that underlying genetic and pathogenetic differences may provide the basis for newer therapeutic approaches.

RECENT FINDINGS

This narrative review highlights the clinical, genetic and pathogenetic characteristics of PP and PRP, their association with PsA and recent developments in their treatment, especially with biologic agents targeting IL-36 and other cytokines of pathogenic relevance.

SUMMARY

The clinical manifestations of PP and PRP are less well known to rheumatologists than those of psoriasis, and recent advances in our insight on their pathogenesis may eventually overcome the therapeutic difficulties faced by dermatologists and rheumatologists in the management of these diseases and their rheumatologic manifestations.

Ixekizumab successfully treated severe pityriasis rubra pilaris after COVID-19 vaccination

Pityriasis rubra pilaris is an inflammatory dermatologic disorder of unknown cause. We report a 67-year-old man with Pityriasis rubra pilaris might induced by COVID-19 vaccination. The patient developed the lesions after the first dose of vaccine and significantly aggravated after the second dose. He had poor effect and liver function impairment developed after acitretin used, but achieved satisfactory efficacy after replacement to ixekizumab, an interleukin-17A inhibitor.

A case of classic adult pityriasis rubra pilaris successfully treated with a combination of acitretin and ustekinumab: A case report

Classic adult pityriasis rubra pilaris is a severe papulosquamous disease that tends to resolve in 3-5 years but can have a devastating impact on patients while active. It shares features with psoriasis, but treatment remains largely empiric, based on case reports and series. The condition is often refractory to treatment, especially initially, with topical corticosteroids and oral acitretin the more commonly employed agents. Relatively high doses of acitretin are needed for adequate response, and adverse events often limit adherence. Given the similarity to psoriasis, biologic agents approved for psoriasis have been used with good effect in classic adult pityriasis rubra pilaris and show better tolerance than other agents. In this report, we describe the successful use of a combination of acitretin and ustekinumab in a case of classic adult pityriasis rubra pilaris.

CARD14-associated papulosquamous eruption (CAPE) in pediatric patients: Three additional cases and review of the literature

CARD14-associated papulosquamous eruption (CAPE) is a proposed term that encompasses features ranging from psoriasis to pityriasis rubra pilaris (PRP) in association with CARD14 mutations. The early onset of the disease, prominent facial involvement, family history of an autosomal dominant trait, and poor response to conventional treatment are characteristics of CAPE that distinguish it from classical psoriasis and PRP. We describe the clinical features, family history, and response to therapy in three unrelated children with CAPE and compare these characteristics with those of previously described pediatric patients. Testing for CARD14 mutations in children with early onset of features of psoriasis or pityriasis rubra pilaris and resistance to conventional therapy should be considered.

Interleukin 36 expression in psoriasis variants and other dermatologic diseases with psoriasis-like histopathologic features

BACKGROUND

Elevated epidermal interleukin (IL)-36 expression distinguishes psoriasis from eczematous dermatitis, but other psoriasiform dermatitides (PDs) have not been thoroughly investigated for IL-36 expression. In this study, we assess the IL-36 staining pattern (IL36-SP) in psoriasis variants and other PDs including lichen simplex chronicus (LSC), prurigo nodularis (PN), lichen planus (LP), tinea, pityriasis rubra pilaris (PRP), mycosis fungoides (MF), pemphigus foliaceus (PF), acute generalized exanthematous pustulosis (AGEP), impetigo (IMP), and syphilis (SY).

METHODS

IL-36 immunostaining was performed on 307 cases of psoriasis and various PDs. IL36-SP in the upper epidermis was graded on a scale of 0-4.

RESULTS

High IL36-SP occurred in all variants of psoriasis, as well as in AGEP, PRP, PN, tinea, IMP, and LP (P > 0.05). SY, PF, LSC, and MF showed a lower IL36-SP (P ≤ 0.05) compared with psoriasis.

CONCLUSION

All variants of psoriasis exhibit high IL36-SP. IL-36 staining can assist in differentiating MF, PF, SY, and LSC from psoriasis, particularly MF and LSC, which have consistent low IL-36 expression. AGEP, PRP, tinea, IMP, PN, and LP exhibit high IL-36 expression similar to psoriasis, indicating Th17 activation in these diseases.

Paeoniflorin suppresses allergic and inflammatory responses by promoting autophagy in rats with urticaria

Paeoniflorin (PF) has been reported to be effective against several skin disorders, such as allergic contact dermatitis and psoriasis; however, it remains unclear whether PF can protect against urticarial lesions. Herein, the effects of PF on rats with urticarial lesions and the possible underlying mechanism were investigated. The effects of PF administration on a rat model of ovalbumin-induced urticarial-like lesions were evaluated via pathological analysis using hematoxylin-eosin staining. Toluidine blue staining was performed to detect mast cells and ELISA was performed to determine serum histamine levels. PF-induced regulatory effects on autophagic activity and the potential underlying mechanism of this were also investigated using transmission electron microscopy, immunohistochemistry and reverse transcription-quantitative PCR. It was demonstrated that PF suppressed allergic and inflammatory responses to improve urticarial lesions, as evidenced by the attenuation of pathological abnormalities, mast cell infiltration and histamine secretion. Mechanistically, PF treatment was found to markedly limit the production and release of inflammatory cytokine interleukin (IL)-23, while the levels of IL-17 remained unchanged. PF intervention led to an increased number of autophagosomes, along with higher levels of light chain 3B (LC3B) and Beclin-1, and lower levels of P62, indicating that PF could augment autophagic activity in urticarial lesions. PF treatment increased the expression of liver kinase B1 (LKB1) and AMP-activated protein kinase-α (AMPK-α), contributing to the PF-enhanced autophagic activity. In conclusion, PF could effectively improve urticarial lesions by inhibiting inflammatory cytokine IL-23 and increasing the autophagic activity via the LKB1/AMPK-α pathway.

Evaluation of Ixekizumab Treatment for Patients With Pityriasis Rubra Pilaris: A Single-Arm Trial

Importance

Pityriasis rubra pilaris is a rare and disabling cutaneous disease that is frequently recalcitrant to conventional therapies and appears to involve interleukin (IL)-17 overexpression.

Objective

To investigate the clinical response and safety of ixekizumab in treating pityriasis rubra pilaris.

Design, Setting, and Participants

Single-arm, investigator-initiated trial conducted in adult patients with moderate to severe pityriasis rubra pilaris at a single-center academic university from June 2018 to January 2020. A total of 41 patients were screened, 12 were enrolled, and 11 completed the full duration of therapy. A referred, consecutive sample was used during participant selection. The treatment period and primary outcome occurred over 24 weeks with additional patient follow-up through 36 weeks.

Intervention

Subcutaneous administration of ixekizumab, a humanized IgG4 antibody that binds IL-17A, at the US Food and Drug Administration-approved dosing schedule for treatment of psoriasis for 24 weeks.

Main Outcomes and Measures

The primary outcome was the mean change in Psoriasis Area and Severity Index at 24 weeks. Secondary outcomes included change in affected body surface area, quality of life, induction of sustained remission, and association of improvement with CARD14 genetic variations and cutaneous cytokine expression.

Results

A total of 12 white patients (mean [SD] age, 49.8 [15.1] years; 8 male [67%]) were enrolled between June 2018 and April 2019, with 11 completing the full course of intervention. The mean (SEM) improvements in Psoriasis Area and Severity Index, affected body surface area, and Dermatology Life Quality Index were 15.2 (2.1) (P < .0001), 29.8% (9.3%) (P = .009), and 9.5 (2.5) (P = .004), respectively. The 4 participants with the most improvement in Psoriasis Area and Severity Index at week 24 stayed in remission at week 36 (defined as lack of increase in Psoriasis Area and Severity Index from week 24 through week 36), off therapy. Relative dermal IL-17A expression decreased by a 1.9 log-fold change. No participants had known pathogenic CARD14 variations. There were no serious adverse events.

Conclusions and Relevance

In this single-armed trial, ixekizumab was associated with reduced clinical signs and symptoms of pityriasis rubra pilaris in a subset of patients, including those in whom other systemic therapies have failed.

Trial Registration

ClinicalTrials.gov Identifier: NCT03485976.

The IL-23/IL-17 Pathway in Inflammatory Skin Diseases: From Bench to Bedside

Interleukin-17 (IL-17) is an essential proinflammatory cytokine, which is mainly secreted by the CD4⁺ helper T cells (Th17 cells) and subsets of innate lymphoid cells. IL-17A is associated with the pathogenesis of inflammatory diseases, including psoriasis, atopic dermatitis, hidradenitis suppurativa, alopecia areata, pityriasis rubra pilaris, pemphigus, and systemic sclerosis. Interleukin-23 (IL-23) plays a pivotal role in stimulating the production of IL-17 by activating the Th17 cells. The IL-23/IL-17 axis is an important pathway for targeted therapy for inflammatory diseases. Emerging evidence from clinical trials has shown that monoclonal antibodies against IL-23, IL-17, and tumor necrosis factor are effective in the treatment of patients with psoriasis, atopic dermatitis, hidradenitis suppurativa, pityriasis rubra pilaris, pemphigus, and systemic sclerosis. Here, we summarize the latest knowledge about the biology, signaling, and pathophysiological functions of the IL-23/IL-17 axis in inflammatory skin diseases. The currently available biologics targeting the axis is also discussed.

[Pityriasis rubra pilaris : Successful treatment with ixekizumab]

Pityriasis rubra pilaris is a rare papulosquamous chronic skin disease. The disease often exists for years and is difficult to treat. Not only is it clinically similar to psoriasis vulgaris, but both diseases also have a similar cytokine profile. The successful use of biologicals is frequently reported in case reports. Studies with large numbers of cases are lacking.

Biologics in Dermatology: Off-Label Indications

Skin and subcutaneous diseases affect millions of people worldwide, causing significant morbidity. Biologics are becoming increasingly useful for the treatment of many skin diseases, particularly as alternatives for patients who have failed to tolerate or respond to conventional systemic therapies. Biological therapies provide a targeted approach to treatment through interaction with specific components of the underlying immune and inflammatory disease processes. Advances in the understanding of disease pathophysiology for inflammatory skin diseases and in drug development have ushered in biologic therapies in dermatology. Biologic therapies are molecules that target specific proteins implicated in immune-mediated disease. This review article highlights the increasing evidence base for biologics in dermatology for off-label use.

Off-label dermatologic uses of IL-17 inhibitors

IL-17 inhibitors, including secukinumab, brodalumab, and ixekizumab, have been U.S. Food and Drug Administration (FDA) approved for the treatment of psoriasis. In addition to psoriasis, IL-17 has been implicated in the pathophysiology of other inflammatory skin conditions. This review aims to synthesize and interpret the literature evaluating the off-label dermatologic uses of IL-17 inhibitors. We performed searches in PubMed and ClinicalTrials.gov for clinical trials, observational studies, case series, and case reports evaluating non-psoriatic uses of the three IL-17 inhibitors. Studies evaluated the efficacy of IL-17 inhibitors for the following conditions: hidradenitis suppurativa (HS), pityriasis rubra pilaris (PRP), Behçet's disease, alopecia areata, and allergic contact dermatitis. Based on the available literature, secukinumab appears to be a potential treatment for HS, PRP, and Behçet's disease, while ixekizumab appears to be a potential treatment for HS and PRP. However, more clinical trials data are needed to adequately assess the safety and efficacy of IL-17 inhibitors for the treatment of these conditions.

Histopathologic findings characteristic of CARD14-associated papulosquamous eruption

BACKGROUND

Pathogenic mutations in caspase recruitment domain-containing protein 14 (CARD14) lead to CARD14-associated papulosquamous eruption, which shares clinicopathologic findings with psoriasis and pityriasis rubra pilaris. We aimed to describe distinguishing histopathologic features of CARD14-associated papulosquamous eruption.

METHODS

This retrospective study examined the histopathologic features of specimens from patients with confirmed CARD14-associated papulosquamous eruption and adult patients with plaque psoriasis and pityriasis rubra pilaris.

RESULTS

Lesional skin biopsies from patients with CARD14-associated papulosquamous eruption consistently showed alternating checkerboard parakeratosis and orthokeratosis, acanthosis without acantholysis, and dilated vessels in the dermal papillae, with some cases also showing follicular plugging.

CONCLUSION

CARD14-associated papulosquamous eruption has a range of findings, with a predominance of features typically associated with pityriasis rubra pilaris.