dermatologic disorders
Pityriasis Rosea
Symptoms and Signs of Pityriasis Rosea
The condition classically begins with a single, primary, 2- to 10-cm herald patch that appears on the trunk or proximal limbs. A general centripetal eruption of 0.5- to 2-cm rose- or fawn-colored oval papules and plaques follows within 7 to 14 days. The lesions have a scaly, slightly raised border (collarette) and resemble ringworm ( Tinea Corporis (Body Ringworm) ). The rose or fawn color is not as evident in patients with dark skin. Patches that appear more pink in patients with light skin appear violaceous and/or hyperpigmented in patients with dark skin. Most patients itch, occasionally severely. Papules may dominate with little or no scaling in children and pregnant women. Children more commonly have inverse pityriasis rosea (lesions in the axillae or groin that spread centrifugally). Initially, most people develop one large scaly patch (herald patch; arrow), and within 1 to 2 weeks, smaller pink patches can occur on the trunk, arms, and legs. Image courtesy of the Public Health Image Library of the Centers for Disease Control and Prevention. In pityriasis rosea, the initial herald patch is followed by centripetal eruption of oval papules and plaques with a slightly raised border, typically appearing along skin lines. Image provided by Thomas Habif, MD. This image shows erythematous and violaceous, ovoid, scaly papules coalescing into patches on the head and torso of a patient with pityriasis rosea. Image courtesy of Karen McKoy, MD. This image shows violaceous, scaly plaques on the back and arms of a patient with pityriasis rosea. Patches that appear more pink in patients with light skin appear violaceous and/or hyperpigmented in patients with dark skin. Image courtesy of Karen McKoy, MD. This photo shows atypical (inverse) pityriasis rosea characterized by oval scaly plaques in the inguinal creases. Image provided by E. Laurie Tolman, MD. Classically, lesions orient along skin lines, giving pityriasis rosea a Christmas tree–like distribution when multiple lesions appear on the back. A prodrome of malaise, headache, and sometimes arthralgia precedes the lesions in a minority of patients. 