Bullous Reaction to Topical Methchlorethamine in Mycosis Fungoides

We describe a patient with mycosis fungoides who developed a bulla shortly after the start of topical methchlorethamine. Dermal-epidermal separation has been reported to occur with topical methchlorethamine on histological examination. It is plausible that the compromised dermal-epidermal junction may manifest as a clinical bulla after a secondary insult. To our knowledge, clinical bulla formation due to topical methchlorethamine has not been reported.