Exacerbation of generalized plaque psoriasis after tuberculin test.

Koebner phenomenon, also known as isomorphic response, is the appearance of active skin lesions in sites of epidermal injury. This manifestation is characteristic of different dermatological diseases, such as lichen planus, vitiligo and psoriasis. We present the case of a psoriatic patient who experienced Koebner phenomenon after Mantoux test, followed by eruption of generalized plaque psoriasis.