Subcorneal pustular dermatosis induced by benzalkonium chloride exposure-two cases.

Abstract

Benzalkonium chloride (BKC) is an organic antiseptic salt used in cleaning agents, and remains prevalent in laundry rinses, antiseptic washes and household cleaning products. We present two adult female patients (aged 32 and 45) who developed subcorneal pustular dermatosis (SPD) secondary to BKC. Both patients had been using laundry rinse containing BKC and presented with 3 months of a pruritic intertriginous and flexural eruption that extended to neck and torso. There was superficial desquamation and micropustules overlying red-brown plaques. Histopathology of both patients revealed epidermal neutrophilic infiltrate, subcorneal pustules, spongiosis, no acantholysis and a negative direct immunofluoresence. Patient 1 (used BKC for ten months), was initially treated as acute generalised exanthematous pustulosis (AGEP) given histological findings, with oral prednisolone 50 mg daily tapering to cessation over one week, but the skin flared within 1 day of cessation. The patient gradually improved over four months with cessation of the BKC. Patient 2 (used BKC for five years) was initially treated empirically as intertrigo complicating atopic dermatitis by her general-practitioner with prednisolone 50 mg daily for one week, resulting in some improvement but the skin also flared rapidly after cessation of prednisolone. The diagnosis of SPD was made on histology, and patient 2 was then treated with oral dapsone 50 mg, in additional to cessation of BKC. Resolution occurred gradually over seven months. The association of the skin eruption with BKC exposure was not identified initially for both patients, and only on later questioning was it revealed that both had used BKC containing laundry rinse for a prolonged period prior to symptom onset. As shown, BKC-induced SCP may occur and can be under-recognised. This highlights the importance of detailed history taking, and accurate clinicopathological correlation. Early recognition of BKC-induced adverse cutaneous reactions and cessation of antiseptic solution use is key to management of this condition.