A 46-year-old male with a past medical history of seizure disorder and recently treated cellulitis presents with a pruritic eruption shown below.

Which of the following is the most likely culprit? 

A. Acetaminophen 

B. Spironolactone

C. Vancomycin 

D. Cephalexin

E. Carbamazepine

Rationale: The clinical photograph above demonstrates annular vesicles/bullae as well as crusting consistent with linear IgA bullous dermatosis. Linear IgA bullous dermatosis can have multiple forms including pediatric, adult, and drug-induced forms. Clinical presentation is variable and includes urticarial plaques/papules, hemorrhagic crusting, and papulovesicles. It can present similarly to dermatitis herpetiformis and in similar locations as well. On direct immunofluorescence, a linear deposition of IgA at the dermal-epidermal junction is seen which can help differentiate the disease from dermatitis herpetiformis (although a small subset of patients with dermatitis herpetiformis can have linear deposition). Several medications have been reported to be associated with linear IgA bullous dermatosis. 

Correct answer: C. Vancomycin

Vancomycin is the most commonly reported medication with linear IgA bullous dermatosis (LABD). Other potential medications include trimethoprim-sulfamethoxazole, NSAIDs (particularly diclofenac), lithium, phenytoin, amiodarone, captopril, furosemide, and infliximab. Many of these can be memorized using the mnemonic V SAD CLiP = Vancomycin, Sulfas, Amiodarone, Diclofenac, Captopril, Lithium, and Phenytoin. Discontinuation of the causative agent is imperative. Dapsone can be quite helpful. 

Incorrect answers: A, B, D, E

Acetaminophen, Spironolactone, Cephalexin, and Carbamazepine are not commonly associated with linear IgA bullous dermatosis. 

Additional reading at Fitzpatrick's Dermatology Chapter 58: Linear Immunoglobulin A Dermatosis and Chronic Bullous Disease of Childhood