More than one-quarter of all individuals with psoriasis develop their disease during childhood or adolescence. The degree of involvement is extremely variable; some children develop only a few localized plaques, while others suffer from generalized skin disease and severe arthritis. Pictured are the typical lesions of psoriasis; the plaques have a red-to-orange hue, are scaly, and are sharply demarcated from the surrounding skin. The symmetrical involvement of the knees is a common pattern; elbows and buttocks are other favored locations for plaques like these.