Propylene glycol allergic contact dermatitis. A quick reference guide for propylene glycol-free topical corticosteroids in Saudi Arabia.

P glycol (PG) is a chemical used in many products as a solvent, vehicle, humectant, or emulsifier.1 Propylene glycol was found to be the most common cutaneous allergen in topical corticosteroids (CS).2 Cosensitization to PG and topical CS can occur,3 making it challenging to choose the appropriate topical CS in a PG-allergic patient. We recently published an article discussing PG-free topical CS in Canada.4 The aim of the present article is to provide a guide for dermatologists and non-dermatologists in Saudi Arabia to choose the appropriate topical corticosteroid in patients allergic to PG. Between August 2012 and July 2013, we carefully searched the ingredients of all topical CS (including the different available formulations) commercially available in Saudi Arabia using the Saudi Food and Drug Authority (SFDA) database and package inserts. Topical CS that contained other active ingredients (for example salicylic acid) were excluded. If a formulation of the same product was listed more than once as different package sizes (for example 30 g cream and 15 g cream), this was counted as one product. A total of 85 topical CS products were identified in the SFDA database. The PG content of 30 (35%) products was unknown due to lack of information regarding the inactive ingredients. Of the remaining 55 products, PG was present in 26 (31% of the total number of products identified). The formulations of the PG-containing topical CS were as follows: 15 creams, 10 ointments, and one lotion. Twenty-nine (34%) of the commercially available topical CS were PG-free. We created a chart containing all the 29 PG-free topical CS available in Saudi Arabia sorted on the basis of their potency and structural class (Table 1). Cutaneous reactions to PG are mostly irritant in nature, but true allergic sensitization does occur. It is challenging to clinically differentiate between irritant and allergic reactions to PG; however, irritant reactions are generally more common, less vesicular, and tend to be associated more with burning sensation than pruritus as compared with allergic reactions. The prevalence of allergic contact dermatitis (ACD) secondary to PG was found to be low (3.5%) by patch