Insect bites
For general measures to prevent insect bites, see here.
Ask about recent travel to exclude vector-borne diseasesWilcock, 2020.
For mild acute reactions to insect bites, topical antipruritics (eg calamine lotion for very moist lesions, lidocaine gel, cooling agents such as menthol, camphor, phenol) may provide symptomatic relief. Avoid over-the-counter preparations that contain sensitisers (eg bufexamac1Therapeutic Goods Administration (TGA), 2020, benzocaine).
If topical antipruritic therapy is inadequate, for mild acute reactions to insect bites on the trunk, arms and legs, use:
1betamethasone dipropionate 0.05% cream or ointment topically, twice daily until lesions and itch have resolved betamethasone dipropionate betamethasone dipropionate betamethasone dipropionate
OR
1mometasone furoate 0.1% cream or ointment topically, twice daily until lesions and itch have resolved. mometasone furoate mometasone furoate mometasone furoate
For mild acute reactions to insect bites on the face, if topical antipruritic therapy is inadequate, use:
methylprednisolone aceponate (adult, or child 4 months or older) 0.1% cream or ointment topically, once daily until lesions and itch have resolved. methylprednisolone aceponate methylprednisolone aceponate methylprednisolone aceponate
For a large local reaction to an insect bite (that is not anaphylactic, and without systemic features), use:
prednisolone (or prednisone) 25 mg orally, once daily for 3 to 5 days. prednisolone prednisolone prednisolone
If local itch persists, prednisolone or prednisone can be followed by topical corticosteroid therapy, as for mild acute reactions to insect bites. Oral antihistamines may be used to help itch; for doses of antihistamines, see hereWilcock, 2020.
If anaphylaxis to an insect bite occurs, treat immediately with adrenaline (epinephrine)—see advice on anaphylaxis. Refer patients who have had a severe or anaphylactic reaction to an allergist.
Occlusive dressings applied with topical corticosteroids can speed healing of nodules and papules caused by insect bites. If the patient has persistent nodules, refer to a dermatologist for intralesional corticosteroid injections.
Assess for secondary infectionWilcock, 2020. Ulcerated lesions can be complicated by cellulitis—for treatment advice, see Cellulitis and erysipelas in the Antibiotic guidelines.