Chlorhexidine allergy
Allergy to chlorhexidine antiseptic.
About chlorhexidine allergy
Chlorhexidine is an antiseptic found in skin-cleansing solutions, surgical scrubs, mouthwashes, some wound dressings and coatings on certain medical devices such as catheters. Because it is so widespread in healthcare, exposure is common, yet it can occasionally cause genuine allergy. Reactions divide into two types: a delayed contact dermatitis, which is a T-cell reaction, and a much rarer but far more serious immediate IgE-mediated allergy that can cause anaphylaxis. The immediate form draws attention because chlorhexidine is often applied just before surgery, so a reaction can be mistaken for a response to an anaesthetic drug.
Milder contact reactions cause itching, redness and eczema-like changes where the antiseptic touched the skin. Immediate allergy can produce hives, swelling and, at worst, anaphylaxis with breathing difficulty and collapse, in line with the rapid onset described. Because chlorhexidine is present in so many products, repeated unrecognised exposure can occur, so identifying it as the cause is important.
Management rests on avoiding chlorhexidine and clearly recording the allergy so antiseptic-free alternatives are used, especially around surgery and dental care. Tell every doctor, dentist, nurse and pharmacist, and consider a medical alert card noting the specific product. Specialist clinics can confirm the diagnosis with testing. A severe reaction is a medical emergency call 999. Follow professional advice about avoidance rather than assumptions.
Common triggers
- Chlorhexidine and products containing it
Symptoms
- Skin rash, hives or itching
- Swelling of the face, lips or throat
- Wheezing or difficulty breathing
- Dizziness or a drop in blood pressure
- In severe cases, anaphylaxis
Avoidance & management
- Tell every doctor, pharmacist and dentist about the allergy
- Wear a medical-alert bracelet if advised
- Check the ingredients of combination medicines
- Discuss safe alternatives with your prescriber
- Seek emergency care for a severe reaction
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.