Acute juvenile pityriasis rubra pilaris: a superantigen mediated disease?

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.

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.

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.

An unusual cluster of circumscribed juvenile pityriasis rubra pilaris cases

Circumscribed juvenile pityriasis rubra pilaris (PRP) is an uncommon dermatosis. We describe the unusual clustering of circumscribed juvenile PRP cases in our pediatric dermatology clinic in 2011. A retrospective chart review was done of patients presenting during the summer of 2011 with classic findings of circumscribed juvenile PRP. Clinical data including past medical and family history, presenting symptoms, infectious disease history and evaluation, biopsy results, and management were recorded. Seven patients, ages 5 to 19 years, all had strikingly similar skin findings of pink to hyperpigmented, well-defined, scaly papules and plaques on their elbows, knees, dorsal hands, ankles, and Achilles tendons. Four of the seven also had palmoplantar involvement. Four were sibling pairs and the other three were unrelated. Streptococcus pyogenes infection was suspected as a trigger in four of the patients. The unusual clustering of this uncommon disease, along with the occurrence in two sibling pairs, suggests that a genetic susceptibility unmasked by an infectious agent may play a role in its pathogenesis.

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.

Type I Pityriasis Rubra Pilaris: Upregulation of Tumor Necrosis Factor α and Response to Adalimumab Therapy

Background:

Pityriasis rubra pilaris (PRP) has unknown etiology and is often refractory to conventional therapies.

Objective:

To document a PRP patient's response to adalimumab therapy and to highlight the potential role of tumor necrosis factor (TNF) in the development of PRP skin lesions.

Methods:

A patient received adalimumab therapy at standard dosing intervals. In addition, the messenger ribonucleic acid (mRNA) of TNF in the lesional and perilesional normal skin was quantified in two patients with PRP.

Results:

The patient responded to adalimumab therapy and achieved clinical remission by 4 months. There was a significant elevation of TNF mRNA in the lesional skin of PRP.

Conclusion:

TNF upregulation is detected in PRP lesional skin, consistent with the observed clinical efficacy of TNF blockade for the treatment of PRP.

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.

Response of juvenile circumscribed pityriasis rubra pilaris to topical tazarotene treatment

We report juvenile circumscribed pityriasis rubra pilaris (type IV) in a 12-year-old Afghani girl in whom local therapy with tazarotene led to rapid, sustained remission. Tazarotene might be considered a useful treatment for circumscribed pityriasis rubra pilaris.

[Pityriasis rubra pilaris. Case reports and review of the literature]

Various treatment options for pityriasis rubra pilaris (PRP) are evaluated and new aspects of the pathogenesis are reviewed.with. Furthermore, 3 cases of adult onset PRP (type I), treated with acitretin, are presented.