Naproxen allergy
Allergy to naproxen, an NSAID.
About naproxen allergy
Naproxen is a non-steroidal anti-inflammatory drug, or NSAID, used for pain, inflammation and conditions such as arthritis and period pain. As with other NSAIDs, many reactions are not true immune allergy but a pharmacological intolerance: naproxen blocks the COX-1 enzyme, altering the body's inflammatory chemistry and triggering symptoms without IgE antibodies. Because this is shared across the NSAID class, someone who reacts this way frequently reacts to ibuprofen, diclofenac and aspirin too. Separately, genuine IgE-mediated allergy to naproxen alone is possible but less common.
Reactions range from hives, facial swelling and worsening asthma with wheeze, through to, in some cases, anaphylaxis with breathing difficulty and collapse, in keeping with the rapid onset described. A recognised pattern links NSAID sensitivity with asthma and nasal polyps. Some people instead develop delayed rashes, and rarely severe skin reactions occur. The class-wide cross-reactivity is the key issue, because avoiding naproxen alone may not prevent reactions if other NSAIDs are taken.
Management rests on avoiding the drug and, where advised, other NSAIDs, and on telling every doctor, dentist and pharmacist, since these medicines appear in many over-the-counter products. Specialist assessment clarifies whether the problem is true allergy or a class effect and identifies safer options. A severe reaction is a medical emergency call 999. Never take, re-take or dose the medicine without professional advice.
Common triggers
- Naproxen 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.