Pityriasis rubra pilaris: algorithms for diagnosis and treatment

Severe pityriasis rubra pilaris complicated with Kaposi's varicelliform eruption and cutaneous MRSA infection case report

A 62-year-old woman presented to our hospital with erythroderma affecting 100 % of body surface area, skin scaling and a body temperature of 37.3o C. The lesions initially appeared on her scalp 6 months prior, then psoriasis was diagnosed. Topical corticosteroids were prescribed, which were ineffective. After 2 months the rash spread to the rest of the body, accompanied by nail changes and hair loss. The patient was subsequently admitted to the local hospital, where following clinical evaluation, oral methotrexate 10 mg once weekly was initiated for 6 weeks. Despite the administered treatment the patient's health and skin condition deteriorated, manifesting with an appearance of new lesions. By the time of admission to our hospital erythroderma affecting 100 % of body surface area covered with wide skin scales and punched-out erosions on the torso, lower eyelid ectropion, loss of scalp hair and thickened yellow nail plates were observed. Skin biopsy revealed histological changes consistent with pityriasis rubra pilaris diagnosis. Polymerase chain reaction test from erosions confirmed the presence of herpes simplex virus 1/2 and culture results identified methicillin-resistant Staphylococcus aureus. Given the considerations of pityriasis rubra pilaris, hematologic disorders and paraneoplastic syndrome, a comprehensive work-up for haematological and oncological disorders was conducted, which yielded no significant findings. The patient was treated with intravenous corticosteroids, antibiotics, and antiviral drugs. Isotretinoin was initiated following the histological confirmation of pityriasis rubra pilaris. By the time of discharge, the patient's condition improved. During a follow-up visit 43 weeks after the initiation of isotretinoin, the skin was almost clear. The described case highlights the rare possibility of developing Kaposi's varicelliform eruption in patients with pityriasis rubra pilaris and demonstrates that isotretinoin is a safe and effective treatment option for this condition.

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-1β as a key mediator, orchestrating an NF-κB-mediated IL-1β-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-1β. With the central role of IL-1β 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-1β antagonists in PRP.

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.

HIV: Inflammatory dermatoses

Patients living with HIV may experience a variety of inflammatory dermatoses, ranging from exacerbations of underlying conditions to those triggered by HIV infection itself. This article presents a current literature review on the etiology, diagnosis and management of atopic dermatitis, psoriasis, pityriasis rubra pilaris, lichen planus, seborrheic dermatitis, eosinophilic folliculitis, pruritic papular eruption and pruritus, in patients living with HIV.

Updates on Pityriasis Rubra Pilaris: A Scoping Review

Pityriasis rubra pilaris (PRP) is a rare, inflammatory papulosquamous skin disease with unknown exact etiology. Historically, PRP has been challenging to diagnose, especially during the acute phase, and to treat, due to its unclear pathogenesis. To better inform clinical practice, a literature review was conducted employing a broad search strategy to capture PRP-related published studies between January 1, 2012 to October 31, 2022. Two hundred twenty-one studies were identified, which were categorized into 9 themes: (1) potential causes and triggering factors, (2) comorbidities, (3) diagnostic difficulties, (4) genetics, (5) clinical manifestations and laboratory values, (6) treatment, (7) treatment-related adverse events, (8) quality of life, and (9) other. COVID-19 infection, COVID-19 vaccination, and malignancy were the most commonly reported potential triggering factors. Misdiagnosis is very common during the early acute stages. Pathogenesis and genetic studies have further implicated caspase recruitment domain family member 14 (CARD14) mutations in the development of familial PRP (Type V) and have underlined the overlap between psoriasis and PRP. To date, there are currently no specific and validated scoring systems or tools to assess the severity of PRP. While large, randomized trials are still lacking, biologic agents remain the most effective therapy.

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.

Resolution of Pityriasis rubra pilaris induced ectropion with oral dexamethasone. A case report

An 82-year-old male presented with generalised Pityriasis rubra pilaris (PRP) managed initially by dermatology team. The patient did not respond to first- and second-line treatment, including oral acitretin, steroid creams, and methotrexate, and developed bilateral cicatricial ectropion, for which he was referred to oculoplastic team for surgical management. A head injury resulting in subacute subdural haematoma, managed with a week course of low dose oral dexamethasone, resulted in the improvement of his skin condition and complete resolution of the cicatricial ectropion within a few weeks. Thus, systemic treatment of PRP with oral dexamethasone may be considered sooner in the treatment of cicatricial ectropion in similar cases.

Autoinflammatory Keratinization Diseases-The Concept, Pathophysiology, and Clinical Implications

Recent advances in medical genetics elucidated the background of diseases characterized by superficial dermal and epidermal inflammation with resultant aberrant keratosis. This led to introducing the term autoinflammatory keratinization diseases encompassing entities in which monogenic mutations cause spontaneous activation of the innate immunity and subsequent disruption of the keratinization process. Originally, autoinflammatory keratinization diseases were attributed to pathogenic variants of CARD14 (generalized pustular psoriasis with concomitant psoriasis vulgaris, palmoplantar pustulosis, type V pityriasis rubra pilaris), IL36RN (generalized pustular psoriasis without concomitant psoriasis vulgaris, impetigo herpetiformis, acrodermatitis continua of Hallopeau), NLRP1 (familial forms of keratosis lichenoides chronica), and genes of the mevalonate pathway, i.e., MVK, PMVK, MVD, and FDPS (porokeratosis). Since then, endotypes underlying novel entities matching the concept of autoinflammatory keratinization diseases have been discovered (mutations of JAK1, POMP, and EGFR). This review describes the concept and pathophysiology of autoinflammatory keratinization diseases and outlines the characteristic clinical features of the associated entities. Furthermore, a novel term for NLRP1-associated autoinflammatory disease with epithelial dyskeratosis (NADED) describing the spectrum of autoinflammatory keratinization diseases secondary to NLRP1 mutations is proposed.

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.

The Effectiveness of Anti-Interleukin-17A Treatment for Pityriasis Rubra Pilaris: A Systematic Review

Anti-interleukin-17A (anti-IL-17A) therapy has been increasingly employed as a treatment option for pityriasis rubra pilaris (PRP). In this study, we reviewed all available studies on this topic in the literature to evaluate the efficacy and safety of anti-IL-17A. Our main objective was to assess the current evidence on the efficacy and safety of anti-IL-17A therapy in the management of PRP. We searched for relevant articles on PubMed, MEDLINE, Ovid, Embase, and the Web of Science electronic databases from inception until 2022. Our inclusion criteria were as follows: randomized controlled trials (RCTs), quasi-randomized trials, or prospective observational studies that include PRP patients treated with biological treatments; studies that report clinical outcomes; and studies that compare the treatment modalities, including anti-IL-17, in the English language. A total of 19 articles involving 77 cases were reviewed after applying the inclusion criteria and removing duplicates. We found that type 1 PRP was the most common condition irrespective of gender, and the trunk was the most affected area. The study showed that IL-17 inhibitors had a significant impact on the patients. However, higher-level studies are required to further evaluate the therapeutic and safety effects of the treatment.

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.

Physiotherapy Management of an Adolescent With Pityriasis Rubra Pilaris Along With Rickets

Rickets is an ossification and mineralization disorder of the growth plate before skeletal maturity that is peculiar to children and adolescents. Most children are affected by this deficient disorder throughout their skeletal growth stage, characterized by deformed and soft bones, due to a failure to assimilate and utilize calcium and phosphorus properly. It is most frequent in children aged four months to three years in developing countries. In the Indian subcontinent, it continues to be a major health problem. The majority of rickets symptoms include bone pain, deformity of the bones, and impaired growth velocity. In addition to damaging the skeletal system, it also affects other systems, which results in substantial morbidity. The term "rachitic pneumopathy" has long been used to describe respiratory issues caused by rickets. Pityriasis rubra pilaris (PRP) is an inflammatory rare skin disease that affects children as well as adults of all ages. They can develop PRP's clinical characteristics and individual prognoses are quite varied. Rickets occurring in association with skin diseases is rare. Here, we report an instance of a 15-year-old boy who gave a history of pain and swelling in the knees for the past three months. He couldn't bear weight and had walking difficulty as well. Along with this, he also complained of itchy lesions for nine years. Initially, the lesions were on the right arm, which progressed to the left arm, chest, back and abdomen. Later, they were seen on the lower limbs. After appropriate diagnostic work, he was diagnosed with rickets with pityriasis rubra pilaris. The patient received both medical and physical therapy treatment. The physical therapy rehabilitation program used in this case study significantly improved the patient's functional independence by reducing pain and improving joint mobility, muscle strength, endurance, and gait. After six weeks of rehabilitation, there was an improvement in the ranges of the joint, strength of muscle, gait, and functional independence significantly using physical therapy techniques. This case study shows the value of comprehensive physical therapy in a case of pityriasis rubra pilaris with rickets in a 15-year-old boy.

Updates and Proposed Diagnostic Approach to Psoriasiform Dermatoses

Psoriasiform dermatoses represent a wide array of skin diseases commonly encountered by clinicians and pathologists. While they may present a diagnostic challenge, thorough observation coupled with proper interpretation of subtle additional clinical or histopathologic features provide clues to the correct diagnosis. In this review, we provide updates on emerging entities and develop a systemic approach to establish the pathologic diagnosis, with emphasis on the importance of clinicopathologic correlation.

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.

Successful treatment of a child's pityriasis rubra pilaris (PRP) with ustekinumab and acitretin

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disease that occurs with phenotypic variability in adults of all ages as well as in children. Data on the treatment of PRP is limited. Here, we report a 5-year-old girl with widespread skin involvement and prominent palmoplantar hyperkeratosis who was initially treated for psoriasis. After reevaluation, a diagnosis of PRP was made, and the patient had an excellent therapeutic response to ustekinumab and acitretin.

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.

What's driving dermatology? Contribution title analysis of the largest German Dermatology Congress 2019

Background

Every two years, German-speaking dermatologic specialist groups gather in Berlin to share the latest developments at Germanýs largest dermatologic conference, the Annual Meeting of the Germany Society of Dermatology (DDG). Because this conference has a lasting effect on dermatologic practice and research, understanding what is moving the specialist groups means understanding what is driving dermatology in Germany.

Methods

We used word network analysis to compile and visualize the information embedded in the contribution titles to the DDG Annual Meeting in 2019. We extracted words, contributing cities and inter-connections. The data was standardized, visualized using network graphs and analyzed using common network analysis parameters.

Results

A total of 5509 words were extracted from 1150 contribution titles. The most frequently used words were “therapy”, “patients”, and “psoriasis”. The highest number of contributions came from Hamburg, Berlin and Munich. High diversity in research topics was found, as well as a well-connected research network.

Conclusions

Focus of the well-connected German-speaking dermatology community meeting 2019 was patient and therapy centered and lies especially on the diseases psoriasis and melanoma. Network graph analysis can provide helpful insights and help planning future congresses. It can facilitate the choice which contributors to include as imbalances become apparent. Moreover, it can help distributing the topics more evenly across the whole dermatologic spectrum.

Pityriasis rubra pilaris post-infection due COVID-19: case report

Case description:

32-month-old boy, IgG positive for SARS-CoV-2, presented to the emergency department with dermatologic lesions.

Clinical findings:

Four days before admission, he presented skin eruptions with redness and pruritus on hands and feet. Generalized papular erythema was evidenced, upper extremities with diffuse erythematosquamous plaques, palmoplantar keratoderma, so he was evaluated by a dermatologist who diagnosed pityriasis rubra pilaris.

Treatment and outcome:

rehydrating cream, cetirizine 0.5 mg/kg/day every two days, and prednisolone 2 mg/kg/day in the morning. He was discharged after 14 days, the patient presented clinical improvement, but the erythematous lesion persisted on the trunk and extremities. In the evaluation, after three months, the patient did not show the described lesions, evidencing an improvement and clinical resolution of the dermatological problems.

Clinical relevance:

We report a patient with pityriasis rubra piloris associated with a post-infection by SARS-CoV-2 that had not been described before.

Identification of a pathogenic CARD14 mutation in a 70-year-old woman with pityriasis rubra pilaris: when genetic diagnosis influences choice of treatment strategy

Pityriasis rubra pilaris (PRP) is a rare dermatosis characterised by hyperkeratotic follicular papules, orange-red scaly plaques and palmoplantar keratoderma. The aetiology of the disease is in most cases unclear and treatment can be challenging. Familial cases of PRP may result from pathogenic variants in the caspase recruitment domain family member 14 (CARD14). We present a case of lifelong PRP in a 70-year-old woman, where genetic testing revealed a heterozygote missense variant c.412G>A, p.(Glu138Lys) in CARD14. Therapy with ustekinumab was initiated with remarkable effect, which improved the patient's quality of life significantly.

Erythrodermic pityriasis rubra pilaris treatment: Two case reports and literature review

Pityriasis rubra pilaris (PRP) is a rare inflammatory dermatosis characterized by hyperkeratotic follicular papules and erythematous-desquamative plaques that tend to progressively evolve into erythroderma. Treatment is challenging given that international guidelines are not available and large-scale trials do not exist. Traditionally, many topical and systemic drugs had been used as consolidated agents; recently, biologicals are gaining increasing importance, promisingly dominating the therapeutic scenario ahead. Herein, we present a case series showing the "past" and the "future" therapeutic approaches to erythrodermic PRP, one case treated with acitretin and nb-UVB phototherapy combination, while the other with ustekinumab, performing also a throughout literature review.

Pityriasis in dermatology: an updated review

Dermatology has a very distinctive lexicon. The term pityriasis refers to several dermatologic conditions which all feature scaling of the skin. According to the Merriam-Webster dictionary, the term pityriasis was first used in print in 1684. Although the diseases beginning with the name pityriasis are of diverse causation, they do represent important dermatologic diseases, with some common and others quite rare. It is important for dermatologists to be aware and updated on all pityriasis conditions in dermatology.

Use of Biologics in Pityriasis Rubra Pilaris Refractory to First-Line Systemic Therapy: A Systematic Review [Formula: see text]

Pityriasis rubra pilaris (PRP) is an uncommon, inflammatory, papulosquamous skin disease. Treatment of PRP is challenging as the disease is often refractory to conventional therapies, such as retinoids and methotrexate. There has been an increasing number of studies reporting the successful use of biologic therapy in patients with PRP; however, the data on the efficacy and safety are limited. Our objective was to evaluate the existing evidence for utilizing biologics, whether alone or in combination with established systemic therapies, in patients with treatment-resistant PRP. We systematically reviewed evidence within Medline and Pubmed databases between January 1, 2000, to March 31, 2019. Articles consisted of patients diagnosed with PRP who have failed to respond sufficiently to first-line systemic therapies, or who had comorbidities that precluded their use. In total, 363 unique articles were identified, 56 of which were considered relevant to the clinical question. Of the 56 articles highlighted, 35 met the inclusion criteria and were limited to case series and case studies. Therapy with biologics was found to be successful for both monotherapy (81.1% [27/33]) and when used in combination with existing systemic therapies (87.5% [14/16]). The existing evidence suggests that biologics may be regarded as a tool for PRP treatment alone or in combination therapy with existing treatments, although large-scale randomized clinical trials are necessary to better assess their efficacy and safety.

Pityriasis rubra pilaris as a systemic disease

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disorder of unknown etiology, initially described in 1835. It is characterized by keratotic follicular papules, well-demarcated salmon-colored erythematous scaly plaques interspersed with distinct islands of uninvolved skin, and palmoplantar keratoderma. Is PRP a systemic disease? Skin is mainly affected in PRP. Despite its clinical heterogeneity, PRP could be associated with a variety of rheumatologic, infectious, neoplastic, and other extracutaneous manifestations. We accept the hypothesis of not only an association but also a causative relation between skin and systemic manifestations with possible common underlying pathomechanisms such as systemic immunologic processes and superantigen mimicry.

Systemic therapies of pityriasis rubra pilaris: a systematic review

Pityriasis rubra pilaris (PRP) is a rare papulosquamous disorder. Treatment is challenging; the armamentarium consists of topical corticosteroids, phototherapy, classic systemic treatments such as retinoids or immunosuppressive drugs, and most recently biologicals. However, the relative effectiveness of therapies is unclear. Our objective was to review the published literature on systemic treatment of PRP. A systematic review was conducted on PubMed and the Cochrane Library up to 5 September 2017. Studies evaluating any systemic treatments of PRP (except for historical treatments) were included. Overall, 182 studies met the predefined inclusion criteria, and reported on 475 patients and 652 courses of treatment. 42.0 % (225/514) of all patients treated with retinoids achieved an excellent response (isotretinoin: 61.1 % [102/167], etretinate: 47 % [54/115], and acitretin: 24.7 % [43/174]) compared to an excellent response rate of 33.1 % (53/160) with methotrexate. Therapy with biologicals was successful in 51.0 % of patients (71/133) (ustekinumab: 62.5 % [10/16], infliximab: 57.1 % [28/49], etanercept: 53.3 % [16/30], and adalimumab: 46.4 % [13/28]). This review balances effectiveness, side effects, experience, and drug costs in order to suggest a treatment regimen starting with isotretinoin as first-line, methotrexate as second-line and biologicals as third-line treatment for this difficult-to-treat dermatosis.

Pityriasis Rubra Pilaris With Extensive Follicular Acantholysis Resembling Pemphigus Vulgaris: A Case Report

Pityriasis rubra pilaris (PRP) is a rare, chronic, heterogeneous, papulosquamous inflammatory dermatosis of unknown etiology. Although erythematous scaly patches characterize the classic presentation of PRP, a broad range of clinical presentations has been reported. Histologically, PRP is characterized by psoriasiform acanthosis with alternating orthokeratosis and parakeratosis and rarely small acantholytic foci. In this article, we report a patient who presented with diffuse erythroderma and extensive acantholysis mimicking pemphigus vulgaris histologically.

Successful Treatment of Pityriasis Rubra Pilaris with Ixekizumab

Pityriasis rubra pilaris is an inflammatory dermatologic disorder of unknown cause and often confounded with psoriasis. It is characterised by hyperkeratotic follicular papules, scaly erythematous plaques, palmoplantar keratoderma, and a progression to generalised erythroderma. Here, we report the case of a 68-year-old man with pityriasis rubra pilaris, who was successfully treated with ixekizumab, an interleukin-17A inhibitor.