The clinical and histomorphological features of pityriasis rubra pilaris. A comparative analysis with psoriasis

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.

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.

Rare Cutaneous Side Effects of Imiquimod: A Review on Its Mechanisms, Diagnosis, and Management

As an immune-response modifier, imiquimod can bind to Toll-like receptors on immune cells and enhance innate and adaptive immune responses, exerting potential antitumor and antiviral effects, which led to its approval by the US Food and Drug Administration for the treatment of actinic keratosis, superficial basal cell carcinomas, and anogenital warts, and to its off-label use in treating many other benign and malignant dermatoses. Although topical administration of imiquimod has been considered well tolerated, an increasing number of cutaneous and noncutaneous side effects are being reported as its clinical applications expand. This review primarily focuses on rare cutaneous side effects. To the best of our knowledge, this is the first article to summarize the mechanism, diagnosis, and management of rare cutaneous side effects of imiquimod, which may help to heighten awareness among physicians, especially dermatologists, about potential imiquimod-induced cutaneous side effects.

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.

Acantholytic pityriasis rubra pilaris associated with topical use of imiquimod 5%: case report and literature review

Topical use of immune response modifiers, such as imiquimod, has increased in dermatology. Although its topical use is well tolerated, it may be associated with exacerbations of generalized cutaneous inflammatory diseases, possibly through the systemic circulation of pro-inflammatory cytokines. This report describes a case of development of pityriasis rubra pilaris, a rare erythematous-papulosquamous dermatosis, in a woman aged 60 years during treatment with imiquimod 5% cream for actinic keratosis. It evolved with erythrodermic conditions and palmoplantar keratoderma, presenting progressive clinical resolution after the introduction of methotrexate. The authors emphasize the importance of recognizing possible systemic reactions associated with the topical use of imiquimod.

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.

The management and genetic background of pityriasis rubra pilaris: a single-centre experience

BACKGROUND

Pityriasis rubra pilaris (PRP) is a rare chronic inflammatory dermatosis with multifactorial aetiology. It is known that particular caspase recruitment domain family member 14 (CARD14) gene mutations are associated with familial PRP and certain forms of psoriasis. Additionally, few data are available about the role of CARD14 gene variants in sporadic PRP. The clinical picture is variable for the different types of PRP, therefore choosing the adequate treatment is often difficult, furthermore there are no specific guidelines for therapy.

OBJECTIVE

Our aim was to survey the efficacy of the applied therapies and to screen the CARD14 gene variants in our PRP patients.

METHODS

In this retrospective study, patients diagnosed with PRP between 2006 and 2016 at our clinic were involved. Besides the follow-up study of the treatments, the genetic analysis of CARD14 gene was performed.

RESULTS

We analysed 19 patients, among whom 17 were diagnosed with type I, one with type III, and one with type V PRP. The majority of the patients were successfully treated with acitretin in combination with systemic corticosteroids, and the remaining patients were treated with other systemic therapies with diverse effects. The genetic screening of CARD14 gene revealed two previously described mutations (rs114688446, rs117918077) and six polymorphisms (rs28674001, rs2066964, rs34367357, rs11653893, rs11652075, rs2289541). Ten of 19 patients carried different CARD14 genetic variants either alone or in combination.

CONCLUSION

Based on our experience, we propose that acitretin and an initial combination of short-term systemic corticosteroid therapy could be a successful treatment option for PRP. Although we identified several CARD14 variants in almost half of our cases, we did not find a correlation between the therapeutic response and the genetic background. Our data support the previous observation that CARD14 genetic variants are not specific to PRP, although they may indicate chronic inflammation.

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.

Nuclear Factor κB Activation in a Type V Pityriasis Rubra Pilaris Patient Harboring Multiple CARD14 Variants

Pityriasis rubra pilaris (PRP) is a rare papulosquamous skin disorder, which is phenotypically related to psoriasis. Some familial PRP cases show autosomal dominant inheritance due to CARD14 mutations leading to increased nuclear factor κB (NFκB) activation. Moreover, CARD14 polymorphisms have also been implicated in sporadic PRP. A Hungarian PRP patient with childhood onset disease showing worsening of the symptoms in adulthood with poor therapeutic response underwent genetic screening for the CARD14 gene, revealing four genetic variants (rs117918077, rs2066964, rs28674001, and rs11652075). To confirm that the identified genetic variants would result in altered NFκB activity in the patient, functional studies were carried out. Immunofluorescent staining of the NFκB p65 subunit and NFκB-luciferase reporter assay demonstrated significantly increased NFκB activity in skin samples and keratinocytes from the PRP patient compared to healthy samples. Characterization of the cytokine profile of the keratinocytes and peripheral blood mononuclear cells demonstrated that the higher NFκB activation in PRP cells induces enhanced responses to inflammatory stimuli. These higher inflammatory reactions could not be explained solely by the observed CARD14 or other inflammation-related gene variants (determined by whole exome sequencing). Thus our study indicates the importance of investigations on other genetic factors related to PRP and their further functional characterization to bring us closer to the understanding of cellular and molecular background of disease pathogenesis.

A Review on Pityriasis Rubra Pilaris

Pityriasis rubra pilaris (PRP) is an idiopathic, papulosquamous inflammatory dermatosis. It is characterized by hyperkeratotic follicular papules coalescing into orange-red scaly plaques, islands of sparing, and palmoplantar keratoderma. PRP can be subdivided into six clinical subtypes according to Griffiths' classification, based on age of onset, disease extent, prognosis, and other associated features. The sixth subtype of PRP occurs in individuals affected by HIV infection, and retroviral screening in all de novo cases of PRP is advised. Other reported associations include various infections, autoimmunity, drugs, and malignancies, although the true significance of these is still unclear. The genetic basis for familial cases, most commonly categorized under the fifth subtype, has been mapped to gain of function mutations in the caspase recruitment domain family, member 14 (CARD14) gene. Treatment of PRP remains a challenge to this day due to a paucity of high-quality evidence. Therapeutic regimens have been guided mostly by case reports and case series, with the mainstay of treatment being oral retinoids. Recently, biologics have emerged as a promising treatment for PRP. We present a review of the clinicopathologic features, pathogenesis, associated disorders, and treatment of PRP, with an emphasis and critical appraisal of the existing literature on the latter.

Recalcitrant psoriasiform dermatosis of the face: Is it related to pityriasis rubra pilaris?

BACKGROUND

There are patients with recalcitrant psoriasiform plaques that do not fit into conventional categories of facial dermatoses. Our study aims to describe the clinicopathological characteristics of several patients with a unique presentation of persistent psoriasiform facial rashes.

METHODS

This retrospective cross-sectional study analyzed clinical and histological data of known cases of recalcitrant psoriasiform dermatosis of the face diagnosed at National Skin Centre, Singapore, over 10 years.

RESULTS

There were 8 Chinese patients with mean age at onset of 29 years. Majority had pink to pink-orange well-defined plaques with dry scale (n = 6, 75%), distributed mostly on the cheeks (100%) and chin (n = 7, 88%). Hyperkeratosis, parakeratosis, preserved granular layer and psoriasiform hyperplasia were showed in all biopsies. Other common findings included subtle subcorneal acantholysis, "checkerboard" alternating ortho-/parakeratosis, vacuolated keratinocytes and follicular plugging. All patients showed little treatment response. One patient eventually developed features of type II pityriasis rubra pilaris (PRP). Our study was limited by its small sample size and lack of a pre-existing diagnostic code.

CONCLUSIONS

This recalcitrant psoriasiform facial dermatosis seems to be a distinct entity, with consistent and reproducible clinical features and a PRP-like histology, bearing some resemblance to the recently described condition-facial discoid dermatosis.

Histopathology of Cutaneous Inflammatory Disorders in Children

Inflammatory dermatoses encompass a variety of histologic patterns that affect different portions of the skin. In spongiotic, psoriasiform, lichenoid, pityriasiform, and blistering disorders, there are predominately epidermal and junctional activities with variable superficial dermal inflammation. Hypersensitivity reactions can show either epidermal or mostly dermal changes depending on whether the exposure of the exogenous allergen occurs through an external or internal route, respectively. Exceptions include erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis, where the etiology is often due to infection or ingested medications, but the histologic features are almost exclusively confined to the epidermis and dermoepidermal junction. Autoimmune disorders are unique in that lesions typically incorporate a mixture of epidermal and dermal inflammatory patterns with periadnexal inflammation, while the vast majority of vasculitis/vasculopathy and alopecia have changes limited to only the vessels and hair follicles, respectively. It is critical to recognize that a relatively limited number of histologic patterns are seen in a large array of clinical entities. Therefore, clinicopathologic correlation and careful examination of histologic details are of the utmost importance when evaluating skin biopsies for inflammatory disorders.

[Pityriasis rubra pilaris]

Pityriasis rubra pilaris is a rare heterogeneous dermatosis associating three clinical signs to different degrees: follicular corneal papules, reddish-orange palmoplantar keratoderma and erythematosquamous lesions that may in some cases be very extensive, interspersed with patches of healthy skin. The aetiology is unclear, and in most cases, the trigger factors consist of trauma or infection, probably in subjects with an existing predisposition. In other cases, the condition is associated with immunological disorders or, in familial cases, genetic keratinisation abnormalities similar to ichthyosis. Given the widely varying signs, several classifications have been proposed, based on clinical criteria and outcomes. The outcome varies in accordance with the clinical forms involved. Therapeutic approaches are poorly qualified and there have been no clinical trials due to the rarity of the disease. However, the best results appear to have been obtained using oral retinoids, with second-line therapy comprising methotrexate and cyclosporine. The landscape of therapeutic strategy seems to be changing with the advent of new anti-tumour necrosis factor and anti-interleukin-12/23 antibodies.

Epidemiologic, Clinicopathologic, Diagnostic, and Management Challenges of Pityriasis Rubra Pilaris: A Case Series of 100 Patients

IMPORTANCE

Pityriasis rubra pilaris (PRP) is a rare papulosquamous disorder with limited epidemiologic and clinicopathologic data. Little information is available on long-term outcomes, comorbidities, and treatment efficacy.

OBJECTIVE

To evaluate objective and subjective disease experience metrics from the perspectives of patients and clinicians.

DESIGN, SETTING, AND PARTICIPANTS

One hundred patients with a putative diagnosis of PRP and who elected to participate completed a comprehensive survey, followed by acquisition of their medical records, including histopathology slides and reports. The data were analyzed separately from the health care clinician and the patient perspectives. Two academic dermatologists examined clinical notes, pathology reports, and photographs, confirming diagnoses via predetermined criteria. Patients were categorized into 4 levels of diagnostic certainty to allow stratification of the findings for subgroup analysis. Patients with a diagnosis of PRP were solicited through patient support organization websites.

MAIN OUTCOMES AND MEASURES

Clinical outcomes, unexpected association of comorbidities, and efficacy (or lack of it) of various treatment modalities.

RESULTS

Among the 100 patients, 50 were diagnosed as having classic, unquestionable PRP. The patients were a median of 61 years old (range, 5-87 years), and 46% were female. Fifty were categorized as level 1 diagnostic certainty, 15 as level 2, 30 as level 3, and 5 as level 4. Of the level 1 patients, 13 (26%) were correctly diagnosed at initial presentation; diagnosis was delayed, on average, by 29 months (range, 0.25-288 months; median, 2 months); and 27 (54%) having undergone 2 or more biopsies. At enrollment, PRP symptoms had persisted in 36 patients (72%) for an average of 58 months (range, 1-300 months; median, 30 months). Thirty-one patients (62%) had comorbidities, including hypothyroidism (20%). Nearly all patients (98%) received some form of therapy. Patients cited topical emollients, corticosteroids, and salicylic acid along with oral retinoids, methotrexate, and tumor necrosis factor inhibitors as most helpful.

CONCLUSIONS AND RELEVANCE

Pityriasis rubra pilaris remains a challenging diagnosis without established and specific treatment. Our data highlight new potential avenues for research with therapeutic perspective.

Recent advances in understanding ichthyosis pathogenesis

The ichthyoses, also known as disorders of keratinization (DOK), encompass a heterogeneous group of skin diseases linked by the common finding of abnormal barrier function, which initiates a default compensatory pathway of hyperproliferation, resulting in the characteristic clinical manifestation of localized and/or generalized scaling. Additional cutaneous findings frequently seen in ichthyoses include generalized xerosis, erythroderma, palmoplantar keratoderma, hypohydrosis, and recurrent infections. In 2009, the Ichthyosis Consensus Conference established a classification consensus for DOK based on pathophysiology, clinical manifestations, and mode of inheritance. This nomenclature system divides DOK into two main groups: nonsyndromic forms, with clinical findings limited to the skin, and syndromic forms, with involvement of additional organ systems. Advances in next-generation sequencing technology have allowed for more rapid and cost-effective genetic analysis, leading to the identification of novel, rare mutations that cause DOK, many of which represent phenotypic expansion. This review focuses on new findings in syndromic and nonsyndromic ichthyoses, with emphasis on novel genetic discoveries that provide insight into disease pathogenesis.

Severe, Disfiguring, Pityriasis Rubra Pilaris in a Woman in the Dominican Republic: Histopathologic Diagnosis and Response to Antiretroviral Therapy

Pityriasis rubra pilaris (PRP) is a poorly understood dermatologic condition usually accompanied by keratoderma and intense erythroderma with islands of unaffected skin. The PRP categories include HIV-associated PRP VI. A 23-year-old HIV-infected, dark-skinned woman in the Dominican Republic developed an extremely severe, disfiguring process characterized first by a dry scaly rash involving her face, trunk, and extremities with hyperpigmentation and islands of spared skin and minimal erythroderma, followed by alopecia and development of a thick horny layer on the scalp and face. The condition, histologically proven to be PRP, was accompanied by fever, wasting, and decline in CD4 count. Initiation of combination antiretroviral therapy (cART) was followed by rapid and sustained resolution of PRP. Nine years after ART initiation, she remains well, with viral suppression and immune recovery, without PRP recurrence but with sparse hair regrowth and facial scarring. In some dark-skinned patients, severe PRP may not feature characteristic erythroderma but will respond to combination ART.

Surgical Management of Cicatricial Ectropion in Pityriasis Rubra Pilaris

Pityriasis rubra pilaris is an idiopathic, papulosquamous dermatological disease. It is clinically and histologically distinct from, but may resemble, psoriasis. Pityriasis rubra pilaris can be self-limiting but may also run a protracted, relapsing course. Medical treatment may involve topical emollients, systemic retinoids, methotrexate, and/or tumor necrosis factor antagonists. Ocular complications include cicatricial ectropion. The authors describe the surgical management of 3 patients with cicatricial ectropion secondary to pityriasis rubra pilaris. All patients had procedures involving skin grafts; 1 patient required multiple operations. The management principles are discussed, including the role and timing of surgery, within the context of emerging treatments for pityriasis rubra pilaris. Patients with pityriasis rubra pilaris and cicatricial ectropion should be closely managed by both ophthalmologist and dermatologist. The eyelid position may improve with conservative or surgical measures. If surgery is required, the limitations of skin grafting under these circumstances should be anticipated and patients counseled appropriately.

Pityriasis rubra pilaris: clinicopathological study of 32 cases from Lebanon

BACKGROUND

Pityriasis rubra pilaris (PRP) is an uncommon papulosquamous disorder of unknown etiology. Studies on this condition from our region are lacking.

METHODS

To describe the clinical and histopathological findings as well as response to treatment of all patients diagnosed with PRP at the American University of Beirut Medical Center between 1995 and 2010 and compare our findings with those published in the literature.

RESULTS

Pityriasis rubra pilaris was diagnosed in 32 patients (16 males, 16 females). Age of onset ranged between 2.5 and 70 years. The majority of patients (n=15) were classified as type I (47%) followed by type III (n=9, 28%) and type IV (n=6, 19%). Based on treatment responses, retinoids appear to be very effective in our population as all patients treated with isotretinoin or acitretin had excellent response. In addition to checkerboard alternating orthokeratosis/parakeratosis, which was observed in 31 cases, interesting features, including the presence of follicular plugging in all 21 cases in which follicles were available for examination, eosinophils in 12 cases, and focal acantholysis in three cases were observed.

CONCLUSIONS

Features of patients with PRP in our study are generally comparable to those published in the literature, with minor differences. Microscopically follicular plugging, in addition to checkerboard alternating orthokeratosis/parakeratosis, may serve as clues to PRP diagnosis. The presence of eosinophils and focal acantholysis, observed in a few cases, should not exclude PRP diagnosis.

Biologics in dermatology

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. This review article examines the increasing evidence base for biologics in dermatology, including well-established treatments and novel agents.

Current knowledge in inflammatory dermatopathology

The complex and fascinating spectrum of inflammatory skin disease, and the comprehension of it, is ever expanding and evolving. During the first decade of the 21st century, numerous advances in the understanding of inflammatory disease mechanisms have occurred, particularly in psoriasis and atopic dermatitis. Continuation of this trend will assure a future in which molecular tests for biomarkers of immediate clinical relevance are used in routine patient care, not only for diagnosis but also for prognosis and management. This article focuses on selected recent or noteworthy developments that are clinically relevant for the histologic diagnosis of inflammatory skin diseases.

Familial pityriasis rubra pilaris is caused by mutations in CARD14

Pityriasis rubra pilaris (PRP) is a papulosquamous disorder phenotypically related to psoriasis. The disease has been occasionally shown to be inherited in an autosomal-dominant fashion. To identify the genetic cause of familial PRP, we ascertained four unrelated families affected by autosomal-dominant PRP. We initially mapped PRP to 17q25.3, a region overlapping with psoriasis susceptibility locus 2 (PSORS2 [MIM 602723]). Using a combination of linkage analysis followed by targeted whole-exome sequencing and candidate-gene screening, we identified three different heterozygous mutations in CARD14, which encodes caspase recruitment domain family, member 14. CARD14 was found to be specifically expressed in the skin. CARD14 is a known activator of nuclear factor kappa B signaling, which has been implicated in inflammatory disorders. Accordingly, CARD14 levels were increased, and p65 was found to be activated in the skin of PRP-affected individuals. The present data demonstrate that autosomal-dominant PRP is allelic to familial psoriasis, which was recently shown to also be caused by mutations in CARD14.

Acantholytic pityriasis rubra pilaris associated with imiquimod 3.75% application

Imiquimod is an immunomodulator with both antitumor and antiviral properties. It is currently available in two cream formulations as Aldara (imiquimod 5%) and the newly approved Zyclara (imiquimod 3.75%). Imiquimod has been associated with localized erythema, crusting, and scaling at the site of application. However, more severe generalized skin eruptions including erythema multiforme, psoriasis, and hyperpigmentation have been described. The newly approved imiquimod 3.75% cream is a presumably safer alternative due to its lower concentration. This paper describes the development of generalized acantholytic pityriasis rubra pilaris after the treatment of an actinic keratosis on the forehead with imiquimod 3.75% cream.

Pityriasis rubra pilaris: a review of diagnosis and treatment

Pityriasis rubra pilaris (PRP) is a rare inflammatory dermatosis of unknown etiology, and finding a successful therapy can be challenging. PRP occurs equally in men and women. In some patients, associated autoimmune diseases, infections, or malignancies are possible trigger factors. PRP shows a bimodal age distribution, peaking in the first as well as in the fifth to sixth decade. Its classification into five subgroups is based on age at onset, clinical course, morphologic features, and prognosis. More than 50% of patients are best classified as type I with adult-onset PRP. This form is also characterized by high spontaneous remission rates (80%) within 1-3 years. Clinically, the classical adult (type I) and classical juvenile (type III) forms appear to be the same except for the patient's age. Recently, the designation of a new category of PRP (type VI) has been proposed that is characterized by the presence of HIV infection with different clinical features and a poorer prognosis. Typical morphologic features of PRP are erythematosquamous salmon-colored plaques with well demarcated islands of unaffected skin. Often, keratoderma of the palms and soles is present. In patients with extensive disease, ectropion is a dreaded complication. Histology shows hyperkeratosis, alternating orthokeratosis and parakeratosis in a checkerboard pattern, and focal acantholytic dyskeratosis. Descriptions and therapeutic experiences are mainly based on case reports. Mostly, systemic retinoids, methotrexate, and other immunosuppressive agents as well as UV light therapy are applied, with varying response rates. In recent years, treatment with so-called 'biologics' is becoming more and more popular for treating recalcitrant PRP. We present a review of the clinical features, histopathologic findings, classification, differential diagnoses, and treatment of PRP.

Pityriasis rubra pilaris--a retrospective single center analysis over eight years

BACKGROUND

Pityriasis rubra pilaris (PRP) is a rare papulosquamous dermatosis. We evaluated evaluate co-morbidities, complications, and outcome of treatment regimens.

PATIENTS AND METHODS

This is a retrospective study at an academic teaching hospital. We analyzed all patients with the definite diagnosis of PRP seen since 2001. Epidemiologic data, co-morbidities, response to and course during treatment were investigated.

RESULTS

We identified 10 PRP-patients (6 men, 4 women), mean age 56.4 years, with type I (n = 9) and type IV (n = 1). Three patients had internal co-morbidities (atrial fibrillation with cardiac insufficiency, dilated cardiomyopathy, diabetes mellitus). Two patients needed psychiatric treatment because of depression. PRP caused ectropium (2 x), diffuse effluvium (1 x), and stenosis of the outer ear canal (1 x). We did not observe a spontaneous remission. Among 9 patients with PRP type I, five were treated with acitretin (two of them as Re-PUVA), and two with methotrexate (in one patient combined with fumaric acids). Systemic corticosteroids were not effective. One patient was treated with infliximab i.v., 5 mg/kg body weight. Starting with the first application, inflammatory activity decreased and erythema got paler. The treatment was well tolerated.

CONCLUSIONS

PRP type I is a severe, chronic inflammatory dermatosis responding hesitantly to classic systemic therapies. Tumor necrosis factor-alpha antagonists are an effective treatment option for difficult cases.

Pityriasis rubra pilaris presenting with an abnormal autoimmune profile: two case reports

INTRODUCTION

Pityriasis rubra pilaris is an uncommon inflammatory and hyperproliferative dermatosis of juvenile or adult onset. The etiology of the disease is still unknown.

CASE PRESENTATION

We present the cases of two Caucasian men aged 53 and 48 who presented with pityriasis rubra pillaris type 1; both patients also exhibited an abnormal immunological profile.

CONCLUSION

Pityriasis rubra pillaris is currently classified as a keratinization disorder. The abnormal immunological profile reported in our patients along with the comorbidity of pityriasis rubra pilaris with autoimmune disorders reported in the literature poses the question of a possible pathogenetic role for the immune response in this disorder.

Exacerbation of Pityriasis Rubra Pilaris under Efalizumab Therapy

A 60-year-old woman, diagnosed as having psoriasis vulgaris in 2004 and unresponsive to standard therapies, received weekly subcutaneous injections with efalizumab. Within 9 weeks of treatment a massive aggravation of skin lesions occurred with widespread orange-tinged erythroderma, islands of normal skin on the back and the inner side of the forearms and palmoplantar hyperkeratosis. A biopsy confirmed the clinical diagnosis of pityriasis rubra pilaris. After discontinuation of efalizumab and treatment with oral corticosteroids, acitretin (30 mg/day) and PUVA therapy, the skin lesions continuously improved. Efalizumab, a fully humanized monoclonal antibody against CD11a, inhibits various T cell processes important in the pathogenesis of psoriasis. Efalizumab has been approved for the treatment of moderate to severe psoriasis, but there are no reports in the literature on the use of efalizumab for pityriasis rubra pilaris.