Pityriasis Rubra Pilaris: An Updated Review of Clinical Presentation, Etiopathogenesis, and Treatment Options.

Pityriasis rubra pilaris (PRP) is a rare papulosquamous reaction pattern with a significant impact on quality of life. Type I PRP is the most common PRP variant, presenting as erythematous papules emerging in a follicular distribution and later coalescing into plaques with characteristic islands of sparing; histologically, an alternating pattern of orthokeratosis and parakeratosis is considered the hallmark of PRP (checkerboard hyperkeratosis). Other PRP variants (types II-V) differ in their age of onset and clinical presentation. Type VI PRP is a rare PRP subtype associated with human immunodeficiency virus infection and is occasionally associated with diseases of the follicular occlusion tetrad. Caspase recruitment domain family, member 14 (CARD14)-associated papulosquamous eruption and facial discoid dermatitis are newly described disease states that have an important clinical overlap with PRP, creating shared conundrums with respect to diagnosis and treatment. The etiology inciting PRP often remains uncertain; PRP has been suggested to be associated with infection, malignancy, or drug/vaccine administration in some cases, although these are based on case reports and causality has not been established. Type V PRP is often due to inborn CARD14 mutations. Furthermore, recent literature has identified interleukin-23/T-helper-17 cell axis dysregulation to be a major mediator of PRP pathogenesis, paving the way for mechanism-directed therapy. At present, high-dose isotretinoin, ixekizumab, and secukinumab are systemic agents supported by single-arm prospective studies; numerous other agents have also been trialed for PRP, with variable success rates. Here, we discuss updates on clinical manifestations, present new insights into etiopathogenesis, and offer a survey of recently described therapeutic options.

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.

[Pityriasis rubra pilaris]. / Pityriasis rubra pilaire: une dermatose mal connue.

Pityriasis rubra pilaris is a rare heterogeneous disorder characterized by follicular keratosis, perifollicular erythema and palmoplantar hyperkeratosis. The aetiology is still unknown. In the majority of cases some triggering factors are found such as trauma or bacterial infection, possibly on a predisposed condition. In other cases, some immunological disorders are associated, and in familial cases a genetic disorder of keratinization has been suggested. The evolution is variable according to the clinical type. The treatment is not well defined, and there is a lack of clinical trials. The best results however are obtained with oral retinoids, methotrexate or ciclosporine as alternative therapy. New TNF inhibitors and anti-IL-12/23 showed a good result and could be have interest in the future.

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.