Probable Irritant Contact Dermatitis From Phenylephrine in Eyedrops With Irritant (False-Positive) Phenylephrine Patch Test Reactions

Typically, we have been taught that there are three major etiologies of dermatitis of the eyelids. These include allergic contact dermatitis, seborrheic dermatitis, and atopic dermatitis. The latter two are usually fairly easily resolved by history and examination. In the absence of these two factors, most of the time an eyelid dermatitis is due to contact allergy. This report points out several facts that we should not forget. First is the idea that an irritant contact reaction may be the cause of a periorbital dermatitis. Because the eyelid skin is thin and presumably sensitive, it may be more likely for an irritant reaction to develop in this region, just as it is apparently more likely for an allergic dermatitis to develop in this area. Second, this report points out that a positive patch test reaction is not always caused by an allergy. Dr. Urbani has given us details of the patch test results in this patient and, indeed, although it is impossible to always differentiate an irritant from an allergic reaction on patch testing, the reactions in his patients seem to be very likely of an irritant nature. All too often, we may confuse an irritant with an allergic patch test reaction, especially if we do not perform a late reading a few days after the patches are removed. In addition, this reminds us that it is necessary when testing with nonstandard substances to always test control patients. Phenylephrine is a common additive in ophthalmologic products. The author points out that there have been several previous cases of presumed allergic contact dermatitis to phenylephrine, but it may well be that irritant contact dermatitis is more common.

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.