What are the cutaneous findings in reactive arthritis (Reiter’s disease)?

The classic triad of reactive arthritis (Reiter’s disease) consists of nongonococcal urethritis, conjunctivitis, and arthritis. However, this triad is present in only 40% of the cases at the time of presentation, and the mucocutaneous findings are helpful in establishing the diagnosis. The mucocutaneous findings include a nonspecific stomatitis, nail changes (subungual hyperkeratosis and onycholysis), circinate balanitis, and keratoderma blennorrhagicum. Keratoderma blennorrhagicum is present in about one third of cases and presents as pinpoint erythematous papules that progress to pustules and hyperkeratotic papules and plaques. These are most commonly seen on the bottom of the feet but may also occur on the scalp, elbows, knees, buttocks, and genitalia. Histologically, the findings are identical to the pustules seen in pustular psoriasis.

Wu IB, Schwartz RA: Reiter’s syndrome: the classic triad and more, J Am Acad Dermatol 59:113–121, 2008.