Probable irritant contact dermatitis from phenylephrine in eyedrops with irritant (false-positive) phenylephrine patch test reactions

A 61-year-old white woman developed an acute eczema of the eyelids and periorbital region after application of eyedrops containing 10% phenylephrine hydrochloride (HCI) for an ophthalmologic examination. The patient showed false-positive (irritant) reactions both to eyedrops as is and phenylephrine HCI 10% aqueous after 48 hours, quickly fading at 72 hours, and unremarkable at 96 hours. There were false-positive results in 2 of 19 controls. Patch testing with phenylephrine HCI 1% aqueous, which is the correct testing concentration, was negative in both case patients and controls. Open tests showed a soaplike irritant effect only to 10% aqueous phenylephrine after 48 hours sharply marginated to the test site area. Repeated open application test further confirmed the above findings. Intradermal testing with phenylephrine showed no delayed reactions either in the affected patient or 19 controls. Irritant patch testing reactions do not necessarily indicate a diagnosis of irritant contact dermatitis; however, it is likely that in our patient, phenylephrine at its higher concentration (10%) was responsible for the clinical picture of irritant dermatitis.