Folliculitis after smallpox vaccination: a report of two cases.

Rashes are frequent and potentially serious adverse consequences of smallpox vaccination. Life-threatening rashes must be differentiated from benign, self-limiting ones. Generalized vaccinia, erythema multiforme, and folliculitis are distinct self-limiting entities but may be difficult to differentiate from one another. Two cases of folliculitis after smallpox vaccination are described. Both patients received anthrax vaccination within 2 weeks before smallpox vaccination. Both presented with a papulopustular rash 9 days after smallpox vaccination. Although the rashes were initially diagnosed as erythema multiforme, the clinical features were more consistent with folliculitis. Self-limiting rashes after smallpox vaccination are common and may be difficult to distinguish from each other. These rashes are clinically distinct, with characteristic features. Improvement in diagnosis may help classify the frequency and risk of rashes after smallpox vaccination. The association of vaccine-associated folliculitis, anthrax vaccine, and other potential antigenic triggers should be further explored.