Background: Contact sensitivity deserves to be assessed in acute vulvitis as well as chronic vulvar dermatitis with a specific orientation toward semen allergy whenever the pathology is post-coital.
Observations: Three observations of semen allergy are reported. Two women presented with post-coital vulvitis due to delayed hypersensitivity to semen proteins without associated specific IgE. The type 2 allergy was confirmed by positive patch-tests and disappearance of symptoms when using condoms. Another woman presented with oedematous vulvitis associated with asthma and malaise per and post-sexual intercourse. Positive prick-tests with husband's semen and blood tests for specific IgE led to the diagnosis of type 1 hypersensitivity to semen, with disappearance of both vulvar and systemic symptoms with the use of condoms.
Discussion: Immediate or delayed type hypersensitivity may be discovered using prick and patch tests respectively. The observation of vulvitis or vulvar discomfort should promote such investigations, whenever a post-coital chronology is suggested. The good clinical pertinence of positive skin tests must be emphasized. Although type I hypersensitivity to semen is documented in the literature, with easy detection of specific IgE, delayed type 2 allergy presents as an as yet under-diagnosed etiology of post-coital vulvitis. Patch tests may help to confirm that contact dermatitis may be due to seminal proteins.