Propylene Glycol

An Often Unrecognized Cause of Allergic Contact Dermatitis in Patients Using Topical Corticosteroids

Mohammed Al Jasser, MD; Nino Mebuke; Gillian de Gannes, MD, FRCPC


Skin Therapy Letter. 2011;16(5) 

In This Article

Allergic Contact Dermatitis to PG

Cutaneous reactions to PG are classified into four groups: irritant contact dermatitis, allergic contact dermatitis (ACD), non-immunologic contact urticaria, and subjective or sensory irritation.[4] The incidence of true ACD to PG is unknown. This is primarily attributed to the difficulty in determining the ideal concentration for patch testing that would be nonirritating, but high enough to elicit an allergic response. The majority of skin reactions to PG are irritant in nature, however, true allergic sensitization does occur. The most convincing evidence of allergic sensitization to PG is the development of systemic contact dermatitis after giving PG orally to PG-allergic patients.[5] The overall prevalence of allergic reactions to PG was found to be relatively low (3.5%) by the NACDG.[3] The NACDG currently recommends using a 30% aqueous PG solution for patch testing.[3] In our experience at the University of British Columbia Contact Dermatitis Clinic, the prevalence of positive patch test reactions to PG over a 2 year period was 1.57% (13/828 patients). It was presumed that an increased individual susceptibility to irritation may also be associated with allergic reactivity through reduction of the skin's barrier function and the release of cytokines.2 To confirm an allergy to PG, it has been recommended that positive patch test reactions should be followed by serial dilution patch tests, repeat open application tests or oral challenge tests, or all three of these assessments.[4]


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