Infected Insect Bites

Midge, mosquito, horsefly and flea bites, and the odd wasp or bee sting, are part of a British summer. Almost all are a nuisance rather than a problem. Occasionally bacteria get into the tiny puncture, usually helped by scratching, and the bite becomes genuinely infected. Telling the two apart is the whole skill, and it is what our pharmacist assesses under the NHS infected insect bite pathway.

Why a bite goes wrong, and why most don’t

An insect bite or sting injects saliva or venom that your immune system treats as foreign. Histamine is released and the area becomes red, raised, warm and itchy within minutes to hours. That is inflammation doing its job, not infection. Infection is a separate event: bacteria that live harmlessly on the skin, usually staphylococci or streptococci, get through the broken surface and multiply underneath. Scratching is the usual way in, which is why children’s bites are infected more often than adults’.

The 48-hour rule

Infection needs time to take hold, so it is very unlikely to explain anything in the first two days. A bite that swells dramatically within hours is almost always an inflammatory or allergic response, and an antibiotic will not help it. So the first question is whether 48 hours have passed; if not, self-care is the answer and the pharmacist will show you what to watch for.

After 48 hours, the pattern matters. The pharmacist looks for at least three of: redness (harder to see on brown or black skin, so warmth and swelling carry more weight), pain or tenderness rather than just itch, swelling, and skin that feels hot to the touch. On top of that, the redness or swelling must be spreading outwards, or pus must be coming from the site. If itch is still the main complaint, the bite is inflamed, not infected.

Look-alikes worth ruling out

A large local reaction to a sting, a hot swollen patch that peaks at one to two days and settles over a week, is inflammation. Clusters of itchy bumps with no obvious bite can be folliculitis, hives or, in children, early chickenpox. And a tick bite that develops an expanding round or oval rash days to weeks later, sometimes with a paler centre, is a possible sign of Lyme disease. That is treated differently and always goes to your GP. A tick bite that simply looks infected, with no sign of that rash or a flu-like illness, can still be assessed here.

What the pharmacist checks when you come in

Because the assessment depends on examining the skin, this is normally an in-person consultation in our private room. The pharmacist will ask when and where you were bitten, how the area has changed day by day, whether you feel unwell or feverish, and what you have already tried. They will look closely at the bite, feel for warmth, check whether the redness is spreading, and go through your medicines, medical history and allergies against your NHS record.

If treatment is appropriate, the pharmacist can supply an antibiotic on the NHS in the same visit. If not, you leave with a plan: a line drawn around the edge of the redness so any spread is obvious, a daily photo, and an invitation to return if the area grows past the line or has not improved after three days of self-care. A record of the consultation goes to your GP practice.

Who is referred elsewhere, and why

The pathway covers people aged one and over. Babies under one, and anyone pregnant under 16, are referred to their GP. It does not cover animal or human bites, tick bites showing signs of Lyme disease, bites picked up abroad where a tropical or tick-borne illness is a concern, or stings from unusual or exotic insects. People with conditions that slow healing, such as poor leg circulation, chronic venous disease, lymphoedema or severe obesity, need a GP assessment, and anyone severely immunosuppressed who has signs of infection needs urgent same-day care rather than a pharmacy course. Stings in the mouth or throat, and bites close to the eye, are referred because of the risk to the airway or the eye.

What tips the decision towards an antibiotic

Even when the infection criteria are met, the pharmacist checks for anything that raises the stakes: feeling systemically unwell, pain far worse than the wound would explain, numbness or tingling, or a pocket of pus that may need draining rather than tablets. Any of those means a same-day referral instead. Allergies, particularly to penicillin-type antibiotics, decide which class of antibiotic is suitable, and a handful of medical conditions and drug interactions rule a pharmacy supply out. If an antibiotic for this bite has already failed, your GP takes over.

How an infected bite heals

An uninfected bite usually stops itching within a few days, though redness can linger for up to ten days. With a treated infection, the redness should stop spreading and the pain begin to ease within two to three days; finish the course even so. If things worsen rapidly at any point, or have not improved by the end of the course, you need reassessing by the pharmacist or your GP.

Self-care that genuinely helps

Wash the area with soap and water and pat it dry. A cool damp cloth or a wrapped ice pack for 20 minutes at a time takes the heat and itch out of a fresh bite. An oral antihistamine or a mild steroid cream from the counter calms the itch and, by breaking the scratch cycle, lowers the chance of infection. Keep nails short, especially in children, and leave scabs and blisters alone. If a bee sting is still in the skin, scrape it out sideways with a card edge rather than squeezing with tweezers. Repellent, long sleeves at dusk and checking skin after walks in long grass mean fewer bites to begin with.

Emergencies: 999, NHS 111 or your GP

Call 999 if the lips, tongue, face or throat swell, breathing becomes difficult or wheezy, you feel faint, or someone becomes confused or drowsy after a bite or sting. Treat it as an emergency — 999 or A&E — if redness is spreading fast alongside fever, shivering or feeling very ill, which can signal a serious infection. Use NHS 111 for a sting inside the mouth, many stings at once, or vomiting and dizziness. See your GP for any tick bite with a rash or flu-like illness, a bite in a child under one, and anything the pharmacist has referred on.