Propylene glycol allergy
Contact allergy to propylene glycol in cosmetics.
About propylene glycol allergy
Propylene glycol is a versatile ingredient used as a solvent, humectant and preservative carrier in cosmetics, moisturisers, deodorants, topical medicines and many foods and medicines. It can act as both an irritant and a true allergen. As an allergen it causes delayed, type IV allergic contact dermatitis, with reactions typically appearing 12 to 72 hours after contact, although some people experience a quicker irritant reaction that is not truly allergic. Because it is so widely used, exposure is common, but confirmed allergy is relatively infrequent and can be tricky to interpret.
The rash is itchy and red, sometimes scaly or blistered, appearing where products containing it were applied, such as the face, underarms, hands or areas treated with a medicated cream or gel. As with other ingredients in topical medicines, an allergy may be overlooked when the flare develops in skin already being treated for another condition, and the treatment itself turns out to be the problem.
Diagnosis is by patch testing with a dermatologist, and interpreting results can require care to distinguish allergy from simple irritation; skin-prick testing is not used. Management means checking labels and avoiding propylene glycol in cosmetics and, where relevant, discussing alternative formulations of medicines with a clinician. Emollients aid recovery and topical steroids may be advised for flares. See your GP or a dermatologist if a rash persists despite treatment or you suspect a product ingredient is to blame.
Common triggers
- Propylene glycol and products containing it
Symptoms
- Red, itchy rash (contact dermatitis)
- Dry, cracked or scaly skin
- Blistering or weeping in severe cases
- Burning or stinging where skin met the trigger
Avoidance & management
- Avoid skin contact with the trigger
- Wear gloves or use barrier creams
- Choose products labelled free from the allergen
- Rinse skin promptly after contact
- Use emollients or prescribed steroid creams
Sources & references
Allergy safety: what everyone should know
Mild-to-moderate reaction signs
- Itching, hives or a raised rash
- Swelling of lips, face or eyes
- Tingling mouth, sneezing, runny nose
- Stomach pain, nausea or vomiting
Anaphylaxis — call 999 (UK) or 112 (EU) immediately
- Difficult or noisy breathing, wheeze, persistent cough
- Swelling of the tongue or tightness in the throat
- Dizziness, collapse, pale and floppy (young children)
- Use an adrenaline auto-injector (e.g. EpiPen) at once if prescribed, then call an ambulance even if symptoms improve
Allergy or intolerance? A true allergy involves the immune system and can escalate quickly; an intolerance (e.g. lactose intolerance) is unpleasant but not life-threatening. The symptoms overlap, so self-diagnosis is unreliable.
Getting tested: home-testing kits based on IgG are not diagnostically valid. If you suspect an allergy, ask a GP for referral to an allergy clinic for skin-prick or specific-IgE testing and a supervised food challenge where appropriate.