Papular spongiotic dermatitis of smallpox vaccination: report of 2 cases with review of the literature.

We report 2 cases of nonspecific postvaccinial dermatitis following smallpox vaccination. The patients presented with diffuse, pruritic, erythematous macules and papules 11 days (case 1) and 7 days (case 2) following routine smallpox vaccination. Biopsies of the lesions demonstrated spongiotic dermatitis without evidence of viral cytopathic changes. One case showed a pityriasis rosea-like histologic pattern. The exanthema resolved without sequelae with symptomatic treatment (case 1). Review of historical literature demonstrated the association of a variety of nonspecific cutaneous complications with vaccinia inoculation, including erythema multiforme, urticaria, and pityriasis rosea. The association of these various dermatitides with smallpox immunization is not well known and is likely underreported.