Products that contain benzalkonium chloride (BAK), a commonly used preservative in various personal care products, ophthalmic solutions, nasal sprays, and cleaning agents, should be used with caution in people with compromised skin barriers, according to a recent study published in Dermatitis.

In a retrospective chart review conducted in an outpatient dermatology clinic, a total of 615 patients who were patch tested for suspected allergic contact dermatitis were included in the analysis. The objective of the study was to review positive reactions to BAK among the participants. Of the participants, 70% (432 of 615) had atopic diathesis and 27% (164 of 615) reported a prior history of childhood atopic dermatitis.

The patch test followed the Modified American Contact Dermatitis Society core “standard” series of 70 allergens, including BAK (0.1% concentration in aqueous solution). The patches were removed at 48 hours and an initial reading was performed. Final readings were carried out between 72 hours and 168 hours.

Results were graded based on the International Contact Dermatitis Research Group guidelines, as follows: – (negative); +/– (doubtful: macular erythema only); + (weak: papules and erythema); ++ (strong: papules and edema or vesicles); or +++ (extreme: coalescing vesicles, spreading or bullous reactions). Reactions were graded as negative in 46% (280 of 615) of participants, doubtful in 22% (138 of 615), weak in 22% (134 of 615), strong in 9% (58 of 615), and extreme in 1.0% (6 of 615).

Of the 615 patients, a positive patch test reaction to BAK was reported in 198 (32%). In addition, ++ or +++ reactions were experienced by 64 patients (10%) at their final reading. Those who were BAK positive, on average, were using ≥1 product containing BAK or a potential cross-reactor.

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The investigators concluded that widespread exposure to irritants among patients with dermatitis can predispose them to sensitization. Products that contain BAK or possible cross-reactors should be used with care in people who have compromised skin barriers. Future studies with BAK cross-reactors in BAK-allergic individuals are warranted.

Reference

Isaac J, Scheinman PL. Benzalkonium chloride: an irritant and sensitizer [published online September 5, 2017]. Dermatitis. doi: 10.1097/DER.0000000000000316