Bites & Stings
Symptoms, Causes & Treatment
Understanding insect bites and stings: how to treat them, when reactions are dangerous, and how to prevent and manage severe allergic reactions.
What Are Bites & Stings?
Insect bites and stings are extremely common, particularly during the warmer months. In the UK, the most frequent culprits are mosquitoes, midges, fleas, bedbugs, horseflies, ticks, wasps, bees, and hornets.
Most bites and stings cause only a minor, localised reaction -- redness, itching, swelling, and mild pain -- that resolves within a few days with simple treatment. However, some individuals develop more significant reactions, and a small proportion experience severe allergic reactions (anaphylaxis) that require emergency treatment.
Bites and stings can also, in some cases, lead to secondary bacterial infection if the skin is broken by scratching, or transmit infections (Lyme disease from ticks being the most important example in the UK).
What Are the Symptoms of Bites & Stings?
Bite and sting reactions range from normal local responses to potentially fatal systemic reactions. Knowing the difference is critical.
Immediate: pain, redness, swelling, itching at bite/sting site · Multiple raised welts · Sting still visible in skin · Blistering around bite · Secondary infection: increasing redness, warmth, spreading cellulitis · Tick attachment · Bull's-eye rash (Lyme disease — erythema migrans)
Anaphylaxis: throat swelling, breathlessness, dizziness, collapse — call 999 · Cellulitis spreading rapidly from bite site · Bull's-eye rash (Lyme disease) with fever · Snake or unusual animal bite · Multiple bee/wasp stings (≥10) · Bite near eye, airway, or genitals
Call 999 immediately if a sting causes throat swelling, difficulty breathing, widespread hives, dizziness, or collapse. Use an adrenaline auto-injector immediately if available. Anaphylaxis can be fatal within minutes without treatment.
What Causes Reactions to Bites & Stings?
Bites and stings cause reactions through venom injection, allergen transfer, or direct tissue damage. The type and severity of reaction depends on the organism and individual sensitivity.
Insects inject venom, saliva, or allergens that cause local or systemic reactions. Hymenoptera stings (bees, wasps, hornets) are responsible for most severe allergic reactions and anaphylaxis from bites or stings.
Tick bites in the UK can transmit Borrelia burgdorferi, causing Lyme disease. The bull's-eye rash (erythema migrans, >5cm diameter) appearing 3–30 days after a bite is pathognomonic and warrants antibiotic treatment.
Animal bites (dog, cat, human) carry high infection risk from polymicrobial bacteria including Pasteurella, Staph, and Eikenella. Cat bites are particularly prone to deep infection due to narrow puncture wounds.
Contact dermatitis occurs when skin comes into contact with an irritant (irritant contact dermatitis) or a specific allergen (allergic contact dermatitis via type IV delayed hypersensitivity). Common allergens: nickel, latex, fragrances, preservatives.
Common eczema triggers include wool, synthetic fabrics, dust mites, pet dander, pollen, mould, soaps, detergents, food allergens (in children), and emotional stress. Identifying and avoiding personal triggers reduces flare frequency.
Psoriasis is an immune-mediated chronic inflammatory skin disease. T-cell activation drives rapid keratinocyte proliferation (3–5 days instead of 28–30), producing the characteristic thickened plaques.
Key Risk Factors
How Are Bite and Sting Reactions Diagnosed?
Bite and sting reactions are diagnosed clinically. Skin swab identifies bacterial infection in inflamed bites. Blood tests (tryptase, specific IgE) investigate allergy after anaphylaxis. Lyme serology after tick bites.
How Are Bites & Stings Treated?
Treatment is matched to reaction severity. Local reactions respond to first aid. Anaphylaxis requires adrenaline and emergency care.
Supportive Measures
Remove bee stinger by scraping sideways. Apply ice wrapped in cloth. Take oral antihistamine for itch and swelling. Ibuprofen reduces inflammation. Clean bite wounds with soap and water. Monitor for signs of infection or worsening reaction over 24–48 hours.
Venom Allergy: Long-Term Management
Known bee or wasp venom allergy requires referral to an allergy clinic. Venom immunotherapy (VIT) is highly effective and reduces the risk of future anaphylaxis from >50% to <5%. It involves a course of desensitisation injections over 3–5 years.
When Should You Seek Medical Advice for a Bite or Sting?
Anaphylaxis: throat swelling, difficulty breathing, widespread hives, collapse — call 999 immediately · Multiple stings (over 20 in an adult) causing systemic illness · Sting to the throat or mouth.
You have had a large local reaction to a sting · You have had anaphylaxis and need referral for venom testing · A bite is becoming infected (increasing redness, warmth, swelling, pus) · You have a tick bite and develop a bull’s-eye rash.
How Can You Prevent Bite & Sting Reactions?
Most bite and sting reactions can be prevented or minimised with appropriate precautions, especially for people with known venom allergy.
Remove a tick correctly: grasp it firmly at the skin surface with fine-tipped tweezers; pull upward steadily without twisting or squeezing. Do not use petroleum jelly, nail varnish, or heat. Save the tick in a sealed bag.
If you have had anaphylaxis from a sting or bite, carry two adrenaline auto-injectors (EpiPens) at all times. Wear a medical alert bracelet. Refer to an allergist for venom immunotherapy, which is curative in 85–95% of cases.
Use DEET-containing repellents (20–50% DEET) on exposed skin in tick-endemic areas. Wear long sleeves, tuck trousers into socks. Check for ticks after outdoor activity. Shingles vaccination reduces tick-related disease indirectly.
Frequent, effective milk removal is the most important mastitis prevention. Feed or express every 2–3 hours; never skip feeds. Get breastfeeding support from a midwife, health visitor, or lactation consultant early — before problems develop.
Ensure your baby latches on deeply and correctly. A poor latch causes nipple trauma (cracks), which are an entry point for bacteria. Ask for a latch assessment if breastfeeding is painful.
Seek breastfeeding support immediately if you notice breast hardness, redness, or pain. Early identification and treatment of blocked ducts prevents progression to mastitis and abscess.
Speak to a Clinician About Bites and Stings
Through The GP Service, a licensed clinician can assess bite and sting reactions, prescribe appropriate treatment, and refer to an allergy specialist if anaphylaxis has occurred.
Expert clinical advice, when you need it.
Bites & Stings FAQs
The severity of a sting reaction depends on the insect species, the location of the sting, the number of stings, and individual sensitivity. Known bee or wasp allergy dramatically increases the risk of anaphylaxis from a single sting.
Call 999 immediately if a sting causes throat swelling, difficulty breathing, widespread hives, dizziness, or collapse — these are signs of anaphylaxis, which is life-threatening. Use an adrenaline auto-injector (EpiPen) if available.
Remove the sting by scraping sideways with a card (do not squeeze). Cool the area with ice wrapped in cloth. Take an oral antihistamine. Apply hydrocortisone cream to reduce local swelling and itch. Seek help if the reaction worsens or spreads.
Tick bites themselves are usually painless. The risk is Lyme disease — look for a bullseye rash (erythema migrans) appearing days to weeks after a tick bite in a woodland or rural area. Prompt antibiotic treatment is effective and curative.
A large local reaction (significant swelling, redness, and warmth beyond the sting site) is common and not the same as anaphylaxis. It typically peaks at 48 hours and may take a week to resolve. Antihistamines and ice help manage it.
Venom immunotherapy (desensitisation injections) is available for people with confirmed IgE-mediated allergy to bee or wasp venom. It significantly reduces the risk of future anaphylaxis. Referral to an allergy specialist is required.
Use an insect repellent containing DEET, wear long sleeves and trousers in woodland areas, check for ticks after outdoor activities, and avoid areas with known wasp or bee nests. If you have a known allergy, always carry an adrenaline auto-injector.
Garden spider bites in the UK are rarely significant. False widow spider bites can cause local pain and swelling and sometimes systemic symptoms. No UK spider bite is typically life-threatening, but any bite causing significant symptoms should be assessed by a clinician.