A psoriasis patient on methotrexate 15 mg/week develops new tender erythematous erosive lesions at the site of a recent healing surgical incision. This phenomenon is an example of:

• A Wolf's isotopic response
• B Renbok phenomenon
• C Rupioid psoriasis
• D Köbner (isomorphic) phenomenon ✓

Explanation

The Köbner (isomorphic) phenomenon refers to the appearance of new psoriatic lesions at sites of physical trauma (surgery, scratches, tattoos, injections) in a patient with active psoriasis. It occurs in approximately 24–51% of psoriasis patients. The surgical incision site represents the triggering trauma. Wolf's isotopic response is the opposite — appearance of a new dermatosis at a site of healed herpes zoster. Renbok is appearance of psoriasis-free skin at the site of another dermatosis (e.g., healed herpes zoster creating a psoriasis-free zone). Rupioid psoriasis is a morphological variant with limpet-like (oyster-shell) hyperkeratotic plaques.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.