Targeting IL-1 controls refractory pityriasis rubra pilaris.

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disease with a poorly understood pathogenesis. Through a molecularly driven precision medicine approach and an extensive mechanistic pathway analysis in PRP skin samples, compared to psoriasis, atopic dermatitis, healed PRP, and healthy controls, we identified IL-1ß as a key mediator, orchestrating an NF-κB-mediated IL-1ß-CCL20 axis, including activation of CARD14 and NOD2. Treatment of three patients with the IL-1 antagonists anakinra and canakinumab resulted in rapid clinical improvement and reversal of the PRP-associated molecular signature with a 50% improvement in skin lesions after 2 to 3 weeks. This transcriptional signature was consistent with in vitro stimulation of keratinocytes with IL-1ß. With the central role of IL-1ß underscoring its potential as a therapeutic target, our findings propose a redefinition of PRP as an autoinflammatory keratinization disorder. Further clinical trials are needed to validate the efficacy of IL-1ß antagonists in PRP.

Loss-of-function mutations in Keratin 32 gene disrupt skin immune homeostasis in pityriasis rubra pilaris.

Pityriasis rubra pilaris (PRP) is an inflammatory papulosquamous dermatosis, characterized by hyperkeratotic follicular papules and erythematous desquamative plaques. The precise pathogenic mechanism underlying PRP remains incompletely understood. Herein, we conduct a case-control study involving a cohort of 102 patients with sporadic PRP and 800 healthy controls of Han Chinese population and identify significant associations (P = 1.73 × 10-6) between PRP and heterozygous mutations in the Keratin 32 gene (KRT32). KRT32 is found to be predominantly localized in basal keratinocytes and exhibits an inhibitory effect on skin inflammation by antagonizing the NF-κB pathway. Mechanistically, KRT32 binds to NEMO, promoting excessive K48-linked polyubiquitination and NEMO degradation, which hinders IKK complex formation. Conversely, loss-of-function mutations in KRT32 among PRP patients result in NF-κB hyperactivation. Importantly, Krt32 knockout mice exhibit a PRP-like dermatitis phenotype, suggesting compromised anti-inflammatory function of keratinocytes in response to external pro-inflammatory stimuli. This study proposes a role for KRT32 in regulating inflammatory immune responses, with damaging variants in KRT32 being an important driver in PRP development. These findings offer insights into the regulation of skin immune homeostasis by keratin and open up the possibility of using KRT32 as a therapeutic target for PRP.

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.

Pityriasis Rubra Pilaris: A Multicentric Case Series of 65 Spanish Patients.

INTRODUCTION: PRP is a rare entity of unknown etiopathogenesis. Lack of management guidelines makes it a challenge for clinicians. OBJECTIVE: To add our experience to increase evidence about PRP. METHODS: We performed a retrospective, descriptive and multicentric study of 65 patients with PRP, being the largest European case series of patients with PRP. RESULTS: PRP was more frequent in male patients with an average age of 51 years, but erythrodermic forms presented in older patients (average age 61 years). Six (75%) paediatric patients and ten (60%) non-erythrodermic adults controlled their disease with topical corticosteroids. On the contrary, 26 (68%) erythrodermic patients required biologic therapy as last and effective therapy line requiring an average of 6.5 months to achieve complete response. CONCLUSION: Our study showed a statistical difference in terms of outcome and response to treatment between children or patients with limited disease and patients who develop erythroderma.

Eosinophils in Traditionally Noneosinophil-Rich Dermatoses.

ABSTRACT: The presence or absence of tissue eosinophilia has previously aided in the diagnosis of inflammatory skin conditions. However, recent studies have elucidated the presence of eosinophils in traditionally eosinophil-poor inflammatory skin diseases, such as dermatomyositis (DM), psoriasis, and lichen sclerosus (LS). This systematic review of the literature explores previous studies of tissue eosinophilia in skin biopsies of dermatoses that are believed to be classically poor in eosinophil. We identified 26 studies, the majority of which were retrospective reviews. The percent of specimens with increased eosinophils in psoriasis ranged from 18%-73%, pityriasis rubra pilaris (PRP) 22%-63%, LS 29%-53%, DM 15%-44%, morphea 8%-45%, hypertrophic lichen planus (LP) 0%-21%, and oral LP 0%-4%. These reports of tissue eosinophilia in reputed eosinophil-poor dermatologic conditions present a diagnostic pitfall and suggest that tissue eosinophilia itself should not be used to rule out a diagnosis of one of these conditions.

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.

Early Presentation of Pityriasis Rubra Pilaris Mimicking Tinea Corporis: Diagnostic Challenges of a Rare Skin Condition.

BACKGROUND Pityriasis rubra pilaris (PRP) is a rare chronic inflammatory skin condition characterized by follicular, papulosquamous, reddish-orange scaling, palmoplantar keratoderma, and erythema with islands of sparing. Its heterogeneous clinical presentation makes the diagnosis of PRP quite challenging, especially at the initial presentation, as it can mimic common skin conditions. CASE REPORT We present a case with an early presentation of PRP in a 61-year-old Malay woman with underlying uncontrolled diabetes, and discuss evolving clinical course of her disease. She presented to a primary care clinic with a 3-week history of itchy, ring-like skin lesions that started on her neck and chest but subsequently spread widely on her chest, back, and upper extremities. She was first treated as having extensive tinea corporis but responded poorly to multiple courses of antifungal treatment. An initial skin biopsy that was taken at the dermatology clinic revealed features suggestive of erythema annulare centrifugum. However, despite topical steroid treatment, her skin condition evolved further and she developed generalized erythroderma along with follicular hyperkeratosis and palmoplantar keratoderma. A repeat biopsy finally confirmed the diagnosis of PRP. CONCLUSIONS Making the diagnosis of PRP is challenging for clinicians. However, clinicians should approach any common skin problem that does not respond to treatment appropriately, with consideration of other uncommon skin disorders. A repeat skin biopsy may be considered if there are any doubts about the diagnosis. A clinical and histopathological correlation is important to aid in the diagnosis of PRP.

Pityriasis rubra pilaris with erythema gyratum repens-like eruption and resolution with ustekinumab.

Erythema gyratum repens (EGR) is a rare paraneoplastic disorder often preceding the diagnosis of underlying malignancy by 9 months on average, while pityriasis rubra pilaris (PRP) is an uncommon papulosquamous inflammatory disease. We present the case of a 58-year-old woman with an EGR-like eruption transforming from resolving PRP, without associated malignancy. Her rash dramatically resolved within a month of ustekinumab initiation, which supports this presentation as a unique entity.

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.

Paraneoplastic Pityriasis Rubra Pilaris Preceding Leukemia.

ABSTRACT: Pityriasis rubra pilaris (PRP) is a rare, chronic papulosquamous disorder that presents with scaling plaques, palmoplantar keratoderma, and keratotic follicular papules. Typically, there are distinctive unaffected areas referred to as "islands of sparing." Pityriasis rubra pilaris has been associated with various immunodeficient states and malignancies.The authors conducted a literature review using MEDLINE, PubMed, and Google Scholar, documenting all known cases of PRP associated with malignancy; 15 cases were found in the literature. They also present the case of a 49-year-old White man who, prior to referral to dermatology, was seen in urgent care for widespread pruritic rash. Physical examination in the dermatology clinic revealed confluent, scaly erythematous papules coalescing into plaques with island of sparing involving the trunk and upper and lower extremities. Bilateral palms and soles showed hyperkeratosis with fissuring. He was diagnosed with PRP after punch biopsy and began a new course of topical corticosteroid therapy. Hematology was consulted because of abnormal complete blood count results, and he was subsequently diagnosed with chronic lymphoid leukemia.Treatment of PRP is largely based on clinical experience and may involve corticosteroids, immunomodulators, or biologic therapy. The relationship between PRP and malignancy is unknown. Current theories postulate it may be driven by tumor production of functional peptides or antigen cross-reactivity between cancer cells and the skin. This is the second reported case of PRP as a manifestation of leukemia, and the first of chronic lymphoid leukemia. Although not yet understood, the documented relationship between PRP and malignancy prompts screening for cancer in all patients with new-onset PRP.

Pityriasis rubra pilaris-like eruption following administration of the BNT163b2 (Pfizer-BioNTech) mRNA COVID-19 vaccine.

We describe a case of a pityriasis rubra pilaris (PRP)-like eruption occurring following administration of the Pfizer-Biontech mRNA COVID-19 vaccine, with worsening of the condition following the second dose. To our knowledge, this is the first reported case of a PRP-like eruption as a cutaneous adverse event of the Pfizer-Biontech mRNA COVID-19 vaccine.

Pityriasis rubra pilaris treatment options: A retrospective case series from a tertiary hospital.

Pityriasis rubra pilaris (PRP) is a group of uncommon chronic inflammatory skin conditions with unclear pathophysiology and etiology. To date there is limited published literature and no clinical guidelines for the management of PRP. Infliximab, alone or in combination, is the most widely published successful treatment for adults and etanercept for pediatric populations. We present a case series of patients diagnosed with PRP. Retrospective data were collected from a tertiary Australian dermatology department between January 2010 and December 2019 on patients with PRP. Electronic medical records and pathology database were searched. A total of 13 patients were included. Twelve of the 13 patients used topical agents and three patients attempted narrow-band ultraviolet B phototherapy. All patients received acitretin as first line systemic agent with the dose varying from 10 to 50 mg daily. Six patients treated with acitretin reported adverse events, requiring dose reduction or cessation. Of the nine patients who did not receive a biologic agent, complete clearance of PRP was achieved in five cases. At least one biologic agent was used in four cases with two experiencing a marked improvement. Overall, complete clearance was achieved in six patients. PRP continues to be a challenge to treat with many treatment options used with variable efficacy.

Altered replication stress response due to CARD14 mutations promotes recombination-induced revertant mosaicism.

Revertant mosaicism, or "natural gene therapy," refers to the spontaneous in vivo reversion of an inherited mutation in a somatic cell. Only approximately 50 human genetic disorders exhibit revertant mosaicism, implicating a distinctive role played by mutant proteins in somatic correction of a pathogenic germline mutation. However, the process by which mutant proteins induce somatic genetic reversion in these diseases remains unknown. Here we show that heterozygous pathogenic CARD14 mutations causing autoinflammatory skin diseases, including psoriasis and pityriasis rubra pilaris, are repaired mainly via homologous recombination. Rather than altering the DNA damage response to exogenous stimuli, such as X-irradiation or etoposide treatment, mutant CARD14 increased DNA double-strand breaks under conditions of replication stress. Furthermore, mutant CARD14 suppressed new origin firings without promoting crossover events in the replication stress state. Together, these results suggest that mutant CARD14 alters the replication stress response and preferentially drives break-induced replication (BIR), which is generally suppressed in eukaryotes. Our results highlight the involvement of BIR in reversion events, thus revealing a previously undescribed role of BIR that could potentially be exploited to develop therapeutics for currently intractable genetic diseases.