[Contact dermatitis from hexamidine].

Twenty patients with contact dermatitis to hexamidine, a commonly used antiseptic solution are reported. They have been collected during a 7 months period, thus suggesting that this contact allergy is not infrequent. Hydroalcoholic solution applied on epidermless skin is most frequently responsible for the contact dermatitis. Clinical features are very peculiar with papular semi-spheric and papulo-vesicular lesions being more frequently seen than classical vesicular eczema lesions. Due to this peculiar aspect, contact dermatitis to hexamidine is frequently misdiagnosed. The delay between onset and diagnosis has been sometimes longer than one year. It is four months as a mean. Pathologic aspect of these lesions is unusual too: dermal vasculitis either lymphocytic or with pycnotic polymorphonuclear is the most frequent aspect (14 out of 23 histological sections). Epidermal spongiosis is infrequent (5 cases). Contact dermatitis has usually a long standing evolution despite removal of the allergen and topical cortico-steroid treatment. Patch-test to hexamidine are frequently followed by a worsening of cutaneous lesions. One case of anaphylaxis following patch-testing has been reported. Clinical and pathological features of this contact dermatitis, suggests that humoral immune mechanisms play a key-role in its pathogenesis.