Allergic contact dermatitis from dipropylene glycol in hydrocortisone lotion

A 66-year-old female presented with a 5-month history of intermittent axillary/arm/chest/abdomen/thigh dermatitis. Prior treatments included over-the-counter hydrocortisone lotion and ointment, triamcinolone ointment, and oral prednisone. A skin biopsy from the left breast showed spongiotic dermatitis with eosinophils. Patch testing was performed using the 2021–2022 North American Contact Dermatitis Group screening series (80 allergens) as well as several supplementary series, including cosmetics, preservatives, emulsifiers, medicaments, textiles, and corticosteroids (Chemotechnique Diagnostics, Vellinge, Sweden; AllergEAZE, SmartPractice, Calgary, Alberta Canada) and 15 personal products. Allergens were occluded until day (D) 2 with final readings on D4 and D6. Final reactions (Figure 1) included ++ reactions to dipropylene glycol (DPG; 20% pet.), nickel (5.0% pet.), formaldehyde (2% aq.), and Cortizone-10 Intensive Healing Lotion for Eczema (“as is”, containing DPG, cetyl alcohol, and hydrocortisone); + reactions to nickel (2.5% pet.), tixocortol pivalate (1.0% pet.), formaldehyde (1% aq.), cetylstearyl alcohol (20% pet.), stearyl alcohol (30% pet.), and disperse dye mix (5.6% pet.); and +/− reactions to cetyl alcohol (5% pet.), Dove Invisible Advanced Care Clear Finish antiperspirant (“as is”, containing stearyl alcohol), Mitchum deodorant (“as is”, containing stearyl alcohol), and Walgreen Calamine Plus Itch Relief spray (“as is”, containing diazolidinyl urea). Pertinent negatives included propylene glycol (PG; 30% aq. and 100%). A review of her personal products found that, in addition to the hydrocortisone cream, DPG was listed as an ingredient in another five products (mascara, three facial creams/serums, and nail polish) (Figure 2). After 2 months of avoidance, the patient reported complete clearance. Dipropylene glycol is a mix of three diol stereoisomers (1,1′-oxybis(2-propanol), 2,2′-oxybis(1-propanol), and 2-(2-hydroxypropoxy)-1-propanol) used in fragrances, solvents, and viscosity-controlling agents. DPG may contain 0.24% to 1.0% PG.1 Both molecules are glycols (compound with two hydroxyl groups attached to carbon atoms) and diols (compound with two hydroxyl groups). Differences include the presence of an ether group in DPG. Johansen et al.1 reported a patient with hand dermatitis due to DPG present in a hand lotion; DPG (0.5% pet., 0.5% aq.) was positive but not PG (0.5% aq.). A Danish study found only one positive case in 503 patients tested to DPG (10% aq.).2 A review of our clinic database found an additional four reactions in 625 patients tested to DPG (20% pet.); two also reacted to PG (Table 1). Patch test concentrations and vehicles for PG and DPG vary.3, 4 Serial dilutions of DPG were not performed in our case. Current belief assumes cross-reactivity between PG and DPG, but more studies are needed to address this important question. None of the authors has any conflict of interest to declare. Malina Yamashita Peterson: Conceptualization (equal); formal analysis (equal); investigation (equal); writing – original draft (lead); writing – review and editing (equal). Joohee Han: Conceptualization (equal); writing – review and editing (equal). Erin M. Warshaw: Conceptualization (equal); formal analysis (equal); investigation (equal); supervision (lead); writing – review and editing (equal).

Topic: Contact Dermatitis and Allergies
Subfield: Dermatology
Field: Medicine
Domain: Health Sciences