If you have experienced a rash after applying a skincare product or topical corticosteroid medication, a common ingredient found in these products, known as propylene glycol, may be the culprit.
Propylene glycol is an organic compound that is formulated in many personal care products and pharmaceutical preparations. Research has suggested that individuals who have a sensitivity to propylene glycol may experience a special form of irritation known as allergic contact dermatitis.
Allergic contact dermatitis is an allergic reaction caused by direct contact with an allergen. It typically presents on the skin as a red, inflamed rash, accompanied by itching and minor pain. If the reaction is severe enough, painful blisters may form on the skin. In many cases the rash will spread to other areas of the skin. Accurately identifying the offending allergen can be a challenge. Patch testing is the most effective way of determining what substance is responsible.
This article will review the sources of propylene glycol, studies on its allergic effects, and a listing of corticosteroid medications that are propylene glycol-free.
Sources of Propylene Glycol
It is a colorless, viscous, nearly odorless liquid and is utilized in the manufacturing of many industrial and personal care products. Propylene glycol is used as a plasticizer, solvent (in lacquers and varnishes), and as a component in antifreeze products, lubricants, cutting-fluids, and inks. It is found in food (for coloring, thickening, and flavoring), household cleansers and in many cosmetic and pharmaceutical preparations including topical steroids, antibacterials, antifungals, benzoyl peroxide, and emollients.1
Studies on Propylene Glycol
In a recent study by the North American Contact Dermatitis Group (NACDG), personal care products were found to be the most common sources of exposure to propylene glycol (53.8%), followed by topical steroids, and other topical medications.3 An investigation by the NACDG demonstrated that topical corticosteroids were responsible for 18.3% of the positive patch test reactions to propylene glycol.3
Skin reactions to propylene glycol are mostly irritant, but allergic contact dermatitis to propylene glycol has been well-documented. In a recent study, propylene glycol was found to be the most common allergen in topical corticosteroids, being present in 64% of the steroidal products.7 It was especially common in branded ointments and gels.
In a study that was conducted on a 55-year-old female suffering from severe eyelid dermatitis and a reoccurring case of dermatitis on her left leg, propylene glycol was found to be responsible. For many years, she had been applying a variety of ointments and skincare products (some of which contained propylene glycol) on her leg dermatitis, with only intermittent improvements. Patch testing determined the offending allergen to be propylene glycol. Consequently, she was switched to tacrolimus 0.1% ointment (propylene glycol- and corticosteroid-free) for treating both the eyelid and leg dermatitis. Soon after, her eyelid dermatitis went away. Her leg dermatitis occasionally recurs due to an underlying vein condition.
If you are experience an allergic reaction while taking a corticosteroid medication, you should consult with your doctor. If your doctor suspects a propylene glycol allergy, they may recommend prescribing a propylene glycol-free topical corticosteroid or a tacrolimus ointment, which is a propylene glycol-free steroid-sparing agent.
- Here is a list of some topical corticosteroid preparations that are propylene glycol-free:
- Hydrocortisone 1% (Cortoderm®) 2.5% (Emo-Cort®)
- Desonide 0.05% (Desocort®)
- Fluocinolone acetonide 0.01% (Derma-Smoothe/FS®)
- Betamethasone valerate (Betaderm®) (Prevex®)
- Prednicarbate 0.1% (Dermatop®)
- Triamcinolone acetonide 0.1% (Aristocort®)
- Amcinonide 0.1% (Cyclocort®)
- Desoximetasone 0.05% (Topicort®)
- Diflucortolone valerate 0.1% (Nerisone®)
- Triamcinolone acetonide 0.5% (Aristocort®)
- Betamethasone dipropionate 0.05% (Diprosone®)
- Clobetasol propionate 0.05% (Dermovate®) (Clobex®)
1. Catanzaro JM, Smith JG, Jr. Propylene glycol dermatitis. J Am Acad Dermatol 24(1):90-5 (1991 Jan).
2. Lessmann H, Schnuch A, Geier J, et al. Skin-sensitizing and irritant properties of propylene glycol. Contact Dermatitis 53(5):247-59 (2005 Nov).
3. Warshaw EM, Botto NC, Maibach HI, et al. Positive patch-test reactions to propylene glycol: a retrospective cross-sectional analysis from the North American Contact Dermatitis Group, 1996 to 2006. Dermatitis 20(1):14-20 (2009 Jan-Feb).
4. Funk JO, Maibach HI. Propylene glycol dermatitis: re-evaluation of an old problem. Contact Dermatitis 31(4):236-41 (1994 Oct).
5. Hannuksela M, Forstrom L. Reactions to peroral propylene glycol. Contact Dermatitis 4(1):41-5 (1978 Feb).
6. Jacob SE, Steele T. Corticosteroid classes: a quick reference guide including patch test substances and cross-reactivity. J Am Acad Dermatol 54(4):723-7 (2006 Apr).
7. Coloe J, Zirwas MJ. Allergens in corticosteroid vehicles. Dermatitis 19(1):38-42 (2008 Jan-Feb).
8. Mimesh S, Pratt M. Allergic contact dermatitis from corticosteroids: reproducibility of patch testing and correlation with intradermal testing. Dermatitis 17(3):137-42 (2006 Sep).