Pearls in Dermatology: Koebner’s Phenomenon: Skin Trauma May Trigger Psoriatic Flares

Abstract

An 18-year-old man presented with a 2-week history of erythematous, scaly plaques along his hairline. Streptococcal pharyngitis had been diagnosed using a throat culture 1 month earlier, and the patient had completed a 10-day course of penicillin V potassium. He was concerned that the two conditions were related. His medical history was significant for psoriasis, which had been in remission for several years. The patient denied any other current symptoms or past medical conditions. Physical examination revealed erythematous, scaly plaques on his scalp in addition to his hairline. Further examination revealed several tattoos on his left upper arm, right flank, and upper back. These tattoos had scaly plaques with erythematous bases along many of the ink lines (figure 1). He reported having had these tattoos applied over the previous several months. The remainder of his examination was unremarkable.