New-onset guttate psoriasis following intravesical immunotherapy of Bacillus Calmette–Guerin

Intravesical Bacillus Calmette–Guerin (BCG) is usually a well-tolerated treatment for urethelial carcinoma of the bladder. A 60-year-old male endured multiple erythematous white-scaled maculopapules over his trunk, back, and four extremities after 2 months of the 6-weekly intravesical instillation of BCG. Skin biopsy revealed parakeratotic hyperkeratosis, intracorneal neutrophilic Munro's abscess, and acanthosis. Guttate psoriasis was diagnosed, and he was treated successfully with topical steroid and narrow band UV-B phototherapy. We present the first Asian case of guttate psoriasis associated with intravesical BCG immunotherapy and review the literatures.