The FP diagnosed pityriasis rosea based on clinical appearance, which included a herald patch (see arrow) that had preceded the eruption. (A herald patch—a solitary, oval, flesh-colored to salmon-colored lesion with scaling at the border—is seen in less than a quarter of pityriasis rosea cases.)
Pityriasis rosea is a papulosquamous eruption of unknown etiology. It occurs at all ages but is most commonly seen between the ages of 10 to 35. Peak incidence occurs between the ages of 20 to 29. Gender distribution is essentially equal.
Pityriasis rosea lesions vary from oval macules to slightly raised plaques (0.5 - 2 cm in size). They are salmon colored (or hyperpigmented in individuals with dark skin), and typically have a collarette of scaling at the border. There are no systemic symptoms, and itching occurs in about 25% of patients. The eruption resolves without treatment in 8 weeks in 80% of patients, but can last up to 3 to 5 months for some. A topical steroid or first-generation oral antihistamine can be prescribed to relieve pruritus.
Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Henderson D, Usatine R. Pityriasis rosea. In: Usatine R, Smith M, Mayeaux EJ, et al, eds. Color Atlas of Family Medicine. 2nd ed. New York, NY: McGraw-Hill; 2013: 896-900.
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