The recommendations in this guideline are based on the evidence identified and the experience of the committee.
Most insect bites and stings can be treated at home with simple first aid, with advice from a community pharmacist. Prescribers are unlikely to be involved even when, rarely, symptoms may last for up to 10 days. This is because secondary bacterial infection is rare. The committee agreed that, usually, knowing what caused the bite or sting is unlikely to change how it is treated.
The committee also noted that redness, itchiness, or pain and swelling after an insect bite or sting is much more likely to be an inflammatory or allergic reaction rather than an infection, especially when there is a rapid onset. They recognised that inflammation after an insect bite or sting may appear like an infection but does not mean that antibiotics are needed. The committee noted that the extent of redness from an insect bite or sting may be less visible on darker skin tones, and healthcare professionals should take this into account when assessing insect bites.
The committee agreed that it was important to prompt people to think about whether the bite may be a tick bite, and to check whether erythema migrans is present. This is so that a known or suspected tick bite can be managed appropriately in line with the NICE guideline on Lyme disease.
Although biting insects can carry bacteria on their mouthparts, most infected bites are likely to be secondary bacterial infections that arise from scratching the bite lesion. Symptoms and signs of infection most likely indicate cellulitis and should be treated with antibiotics in line with the NICE guideline on cellulitis and erysipelas.
There is limited evidence with high uncertainty for the use of oral antihistamines in reducing lesion size and itchiness from mosquito bites. However, based on their experience, the committee agreed that oral antihistamines may help to relieve itching. Although the included study of oral antihistamines compared with placebo included only children who were aged 2 years and over, the committee acknowledged that oral antihistamines are also an option for adults and children under 2 years. Not all antihistamines are licensed for treating insect bites and stings, and not all antihistamines are licensed in young children. The committee also discussed the use of sedating antihistamines in children, noting that the BNF for children states: 'sedating antihistamines are occasionally useful when insomnia is associated with urticaria and pruritus'.
No evidence was found for other self-care treatments that are often used in practice (such as topical corticosteroids, topical antihistamines and analgesics). However, studies published before the year 2000 that compared these treatments were not included in the literature search. Given the range of potential self-care treatments and differences in licensed indications, the committee concluded that a community pharmacist is ideally placed to advise people about managing an insect bite or sting at home.
Insect bites and stings are the second most common cause of serious allergic reactions, so the committee agreed that people with symptoms or signs of a serious allergic reaction should be referred for urgent care.
It is also important to consider referral or seeking specialist advice in the following situations:
people who have had a previous systemic allergic reaction to the same type of bite or sting because a serious allergic reaction is more likely
people with a bite or sting in the mouth or throat, or around the eyes
people with a bite or sting from an unusual or exotic insect or spider, because management may be different (for example, certain spider bites can lead to tissue necrosis)
people with fever or persistent lesions after an insect bite or sting from outside the UK because this may indicate a more serious illness such as rickettsia or malaria.