Colophony (rosin) allergy
Contact allergy to rosin in adhesives and cosmetics.
About colophony (rosin) allergy
Colophony, also known as rosin, is a sticky resin obtained from pine and other conifers. It appears in a surprising range of everyday products: adhesive plasters and tapes, some cosmetics and depilatory waxes, glues, varnishes, printing inks, and the rosin used by musicians and gymnasts. Allergy to colophony is a delayed type IV allergic contact dermatitis, so the rash characteristically develops a day or two after contact rather than immediately. It is a fairly common cause of contact allergy and can affect both the general public and people whose work involves adhesives or solvents.
The rash is itchy and red, sometimes scaly or blistered, and tends to appear wherever a colophony-containing product touched the skin, for example under a plaster, around the mouth from lip products, or on the hands. With repeated exposure it can become chronic. People allergic to colophony may also react to balsam of Peru and to some fragrance materials, as these share related resin components.
Diagnosis is by patch testing carried out by a dermatologist, not skin-prick testing. Management means recognising and avoiding rosin-containing products, choosing colophony-free plasters and cosmetics where possible, and using gloves for occupational contact. Emollients and, when advised, topical steroids help settle flares. See your GP or a dermatologist if a rash keeps returning to the same spots or resists simple treatment.
Common triggers
- Colophony (rosin) 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.