Developing Shingles-Induced Koebner Phenomenon in a Patient With Psoriasis: A Case Report

Both shingles and psoriasis are common cutaneous diseases. About 25% of the psoriatic patients develop Koebner phenomenon (KP) after various injuries, and in rare instance, KP may occur at the site of healed or healing shingles. We report a 30-year-old man with 7-month history of scalp psoriasis who developed KP at the areas of developing shingles. Cutaneous examination revealed scaly erythematous papules and plaques located on the scalp and forehead, and groups of clustered erythematous papules with silver scales in the dermatome distributed on the right side of chest wall the prior herpes zoster lesions involved. After removal of the scales on the papules, underlying bleeding points were present. The lesions on chest had good response to anti-psoriatic therapies, as the lesions on scalp did. After a year of follow-up, recurrent psoriasis occurred, but the lesions were located only on the scalp, and the areas of prior occurrence of shingles, because of which we considered diagnosis of recurrent psoriasis rather than relapsing KP for the chest lesions. Not only the healing and healed shingles can trigger KP in psoriasis, but also the developing shingles can cause psoriatic KP at the site of herpes zoster lesions.