Renbök Phenomenon and Contact Sensitization in a Patient With Alopecia Universalis

The document described a patient with concurrent psoriasis and alopecia universalis, where psoriasis plaques on his extremities showed normal hair growth, the only such growth on his body. Biopsies confirmed plaque psoriasis with normal hair follicles and alopecia universalis with a peribulbar lymphocytic infiltrate. The patient's psoriatic plaques cleared with narrow-band UV-B phototherapy, but hair growth was maintained. His scalp alopecia responded to squaric acid dibutylester contact sensitization therapy. This case illustrated how different immune responses can interact, with psoriasis or contact dermatitis taking precedence over alopecia areata, possibly due to cytokine cross-regulation.