Tetracycline allergy
Allergy to tetracycline antibiotics.
About tetracycline allergy
Tetracyclines are a group of antibiotics including tetracycline itself, doxycycline and lymecycline, used for chest infections, acne and other conditions. Genuine allergy is uncommon compared with the penicillins. Several problems attributed to them are not true allergy: stomach upset is a frequent side effect, and increased skin sensitivity to sunlight, causing exaggerated sunburn, is a predictable photosensitivity effect. When genuine allergy occurs it can be immediate and IgE-mediated or, more often, a delayed T-cell reaction.
Allergic reactions can include itching, hives, rash and swelling, and rarely more serious immediate reactions with breathing difficulty. The onset spans minutes to hours, with some rashes appearing after several days, in keeping with delayed skin reactions. Rarely, tetracyclines have been linked to more serious hypersensitivity reactions affecting the skin and organs. Because the drugs share a common structure, a genuine allergy to one may mean caution with the others, so a different class is often chosen.
Management means avoiding the drug where allergy is suspected, while distinguishing this from photosensitivity or stomach intolerance. Tell every doctor and pharmacist so a suitable alternative is selected. A suspected allergy can be assessed by a specialist rather than assumed permanent. A severe reaction with breathing difficulty, swelling or collapse is a medical emergency call 999. Never take, re-take or dose the medicine without professional advice.
Common triggers
- Tetracycline 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.