Definition

Pityriasis rubra pilaris (PRP) is a rare skin disorder that causes inflammation and scaling (exfoliation) of the skin.

Alternative Names

PRP; Pityriasis pilaris; Lichen ruber acuminatus; Devergie disease

Causes

There are several subtypes of PRP. The cause is unknown, although genetic factors and an abnormal immune response may be involved. One subtype is associated with HIV/AIDS.

Symptoms

PRP is a chronic skin condition in which orange or salmon-colored scaly patches with thick skin develop on the hands and feet.

The scaly areas may cover much of the body. Small islands of normal skin (called islands of sparing) are seen within the areas of the scaly skin. The scaly areas may be itchy. There may be changes in the nails.

PRP can be severe. Although it's not life threatening, PRP can greatly reduce quality of life and limit activities of daily living.

Exams and Tests

Your health care provider will examine your skin. The diagnosis is usually made by the presence of the unique skin lesions. (A lesion is an abnormal area on the skin). Your provider may take samples (biopsies) of the affected skin to confirm the diagnosis and rule out conditions that may look like PRP.

Treatment

Topical creams containing urea, lactic acid, retinoids, and steroids may help. More commonly, treatment includes pills taken by mouth such as isotretinoin, acitretin, or methotrexate. Exposure to ultraviolet light (light therapy) may also help. Medicines that affect the body's immune system are currently being studied and may be effective for PRP.

Support Groups

More information and support for people with PRP disorder and their families can be found at:

• National Organization for Rare Disorders -- rarediseases.org/rare-diseases/pityriasis-rubra-pilaris
• PRP Alliance, Inc. -- prpalliance.com

When to Contact a Medical Professional

Contact your provider if you develop symptoms of PRP. Also contact your provider if you have the disorder and symptoms worsen.

References

James WD, Elston DM, Treat JR, Rosenbach MA, Neuhaus IM. Pityriasis rosea, pityriasis rubra pilaris, and other papulosquamous and hyperkeratotic diseases. In: James WD, Elston DM, Treat JR, Rosenbach MA, Neuhaus IM, eds. Andrews' Diseases of the Skin: Clinical Dermatology. 13th ed. Philadelphia, PA: Elsevier; 2020:chap 11.

Patterson JW. Disorders of pigmentation. In: Patterson JW, ed. Weedon's Skin Pathology. 5th ed. Philadelphia, PA: Elsevier; 2021:chap 11.