Anaphylaxis TreatmentAnaphylaxis: hives + breathlessness + swelling + collapse after allergen exposure. Give adrenaline auto-injector (EpiPen) into outer thigh immediately. Call 999. Lie flat with legs raised. A second dose after 5 minutes if no response.
Types of Allergic Reaction
| Type | Mechanism | Examples | Timeframe |
|---|---|---|---|
| IgE-mediated (immediate) | Mast cell degranulation after IgE sensitisation | Peanut allergy, bee sting, latex | Minutes |
| Non-IgE-mediated | T-cell mediated | CMPA in infants, contact dermatitis | Hours–days |
| Intolerance (not true allergy) | No immune component | Lactose intolerance, FODMAP sensitivity, caffeine | Variable; no anaphylaxis risk |
Allergy Testing Options
| Test | What It Detects | When Used |
|---|---|---|
| Skin prick test (SPT) | IgE sensitisation to specific allergens | Food allergy, hay fever, animal allergy — gold standard in clinic |
| Specific IgE (RAST) | Blood test for allergen-specific IgE | When SPT impractical; eczema; on antihistamines |
| Oral food challenge | True clinical allergy vs sensitisation | Diagnose food allergy definitively |
| Patch testing | Type IV (contact) delayed allergy | Contact dermatitis; nickel, fragrance, rubber allergy |
Avoid Unreliable TestsAvoid: IgG food sensitivity tests, hair analysis, vega testing, kinesiology, and ELISA food panels — not evidence-based, not diagnostically useful, frequently false-positive, and lead to unnecessary food restriction. Use NHS allergy clinic testing instead.
What is the difference between food allergy and food intolerance?
Food allergy is immune-mediated (IgE or non-IgE) — can cause anaphylaxis, urticaria, angioedema, and immediate symptoms. Food intolerance is non-immune — causes digestive symptoms, usually delayed — never anaphylaxis. Lactose intolerance is the most common food intolerance.
Who needs an EpiPen?
Anyone with a history of anaphylaxis, or those with asthma + severe food allergy. Prescribed by an allergy specialist after assessment. Two auto-injectors should be carried at all times; trainer devices for practice. School nurses should hold a spare.
What is allergen immunotherapy?
Controlled exposure to increasing doses of allergen (subcutaneous injections or sublingual drops/tablets) to desensitise the immune system. Takes 3–5 years. Most effective for house dust mite, grass pollen, bee/wasp venom, and some food allergies (peanut — now licensed).
What antihistamines are best?
Non-sedating: cetirizine, loratadine, fexofenadine (all OTC) — preferred for daily use. Sedating (chlorphenamine) — causes significant drowsiness; useful at night only. For hay fever, intranasal steroid spray (fluticasone) + antihistamine is more effective than antihistamine alone.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.