An 11-month-old boy was brought to the doctor by anxious parents for the evaluation of persistent diaper dermatitis. Despite trying multiple barrier creams and over-the-counter antifungal products, the rash did not resolve.
Etiology and epidemiology
Psoriasis is a chronic inflammatory condition that has a prevalence of approximately 1% in children.1 Of those who develop psoriasis, up to 30% start with psoriasis in the diaper area, also known as napkin psoriasis, within the first 2 years of life.2 Infantile psoriasis is more commonly preceded by an infection or trauma than in adult psoriasis, and the Koebner phenomenon from repeated wiping and rubbing on a diaper is a likely culprit for napkin psoriasis.3 Family history of psoriasis is also a risk factor for developing this entity, and those who have dissemination of psoriatic plaques beyond the diaper area are at a higher risk of having psoriasis later in life.4
Infantile psoriasis typically presents as a persistent, well-demarcated red plaque with absent or scant scale distributed in the diaper area. The plaques can involve the skinfolds. Some infants may have psoriatic plaques elsewhere on the body, but the groin involvement often precedes the more widespread eruption. Some infants exclusively have involvement of the diaper area.5