A 38-Year-Old Dog Owner With a Blistering, Itchy Rash

Melba Estrella, MD; Alan Snyder; John Plante; Dirk M. Elston, MD

Disclosures

October 29, 2020

Many patients with an apparent allergy to elasticated clothing are not allergic to the elastic itself but rather to the subproducts that result from laundering the elasticated clothing with chlorine bleach.[5,6] Bleached rubber contact dermatitis, also known as "bleached rubber syndrome," is a common type of allergic contact dermatitis that results from allergy to bleached rubber compounds.[6,7] Jordan and Bourlas[6] first described this syndrome in 1975. In a case series of six patients who were allergic to elastic underwear, the investigators demonstrated that the main cause of the syndrome in all the study participants was N,N-dibenzylcarbamyl chloride, the resultant product from the interaction of the accelerator agent zinc dibenzyldithiocarbamate with chlorine laundry bleach.

Repeated bleaching in theory causes greater availability of carbamate compounds, which enhance the allergenicity of the elastic. This increase in allergenicity could help explain the progressive worsening of this patient's rash.

The first step in the diagnosis of allergic contact dermatitis is to determine whether the lesions resolve after avoidance of the offending agent. If the rash persists despite avoidance and empirical topical treatment, patch testing is indicated. Patients with suspected allergic contact dermatitis who have a negative reaction on the initial patch test should undergo additional testing. A patch test is the most useful and cost-effective diagnostic tool to identify allergic contact dermatitis; the sensitivity and specificity range from 70%-80%.[8,9] A commonly used patch test is the TRUE Test baseline series kit, which includes 27 single antigens and eight mixes of allergens that are frequently associated with allergic contact dermatitis, as well as a negative control.

If a patient reacts positively to a rubber mix on the baseline series kit, patch testing for rubber compounds is the next step.[10,11] Kits that contain broken-down rubber ingredients are used to further assess the allergy in question. Uter and colleagues[11] suggested that if the allergy remains strongly suspected despite a negative baseline series patch test, a rubber series kit is warranted to avoid false-negative results. The TRUE Test 5 Rubber Panel kit is a commercially available rubber series kit that contains ubiquitous chemicals used in rubber manufacturing, such as accelerator agents.

A reading of a rubber series patch test in this patient was performed 48 hours after application, then again after 72 and 96 hours. No reaction was visible.

Further questioning about the patient's laundering practices revealed that his wife washed his white clothes with bleach. This finding is consistent with his past history of a similar rash on the ankles that resolved with the use of new socks. Because patch testing typically does not detect carbamyl chloride, the diagnosis was made clinically in this patient.

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