Pityriasis Rubra Pilaris

Excerpt

Pityriasis rubra pilaris (PRP) is a rare inflammatory papulosquamous disorder of unknown etiology. There are 6 clinical subtypes, which occur in both children and adults. Common elements noted across all subtypes include palmoplantar keratoderma and follicular papules coalescing into well-demarcated plaques of various sizes with characteristic reddish-orange hue and non-adherent, flaking scale. More generalized subtypes often demonstrate intervening areas of unaffected skin, known as "islands of sparing," a signature characteristic of PRP. However, this feature may occasionally be found in PRP-mimickers (eg, psoriasis or mycosis fungoides), especially when these patients are erythrodermic.

Patients with PRP have a broad spectrum of presentations, from mild disease isolated to extensor extremities to diffuse erythroderma involving 90% to 100% of body surface area, as well as intense itching, skin tightness, burning, stinging, and pain. In some cases, PRP is self-limited and asymptomatic; however, in symptomatic chronic cases, continued treatment is indicated, primarily consisting of topical treatments for symptomatic management and systemic therapy to reduce inflammation.