Summer Bites: Evaluation and Management of Common Bug Bites

Lilian White
Posted on June 23, 2025

An erythematous, pruritic papule is as ubiquitous to summer as the sun. The differential is broad and includes a mosquito, spider, or other insect bite; scabies infestation; atopic dermatitis; early allergic contact dermatitis; urticaria; folliculitis; photosensitive rashes; and other rashes. Skin infection with methicillin-resistant Staphylococcus aureus (MRSA) may be easily mistaken for a necrotic spider bite.

Some signs may be helpful to distinguish the cause of the bite if the etiology is unknown. Necrosis may raise concern for a spider bite. Multiple lesions or lesions in close contacts may prompt suspicion for MRSA infection. Scabies often causes a rash in near skin creases, is intensely pruritic, and may also be present in close contacts.

Treatment of spider bites is typically limited to supportive wound care and updating a tetanus vaccine if needed (because of the deep nature of the wound). Antivenom for widow spider bites is reserved for severe reactions (ie, abnormal vital signs). Its availability is limited because widow spider bites are not generally life threatening. Recluse spider bites are uniquely characterized by a brown macule or patch and usually resolve in 1-2 weeks. A small percentage become necrotic within 1-2 days and may take weeks to months to heal, often with notable scarring.

Hymenoptera (including bees, wasps, and ants) stings are typically managed with supportive care, with the exception of anaphylactic reactions. If a stinger is left behind, some experts recommend using a credit card or dull blade to sweep across the skin to remove it. An AFP editorial recommends removing the stinger as quickly as possible—regardless of the technique —to reduce the amount of venom injected into the wound (thereby reducing the risk of anaphylaxis). Supportive treatment includes cold compresses, topical or oral antihistamines, and, in more severe reactions, oral steroids. In patients with a history of anaphylaxis, allergy testing and treatment with immunotherapy is recommended to reduce the risk of future episodes of anaphylaxis.

Mosquito bites may cause localized allergic reactions. Although studies are lacking, topical corticosteroids are typically offered for treatment. Application of N,N-diethyl-m-toluamide (DEET) of 20% to 35% concentration is recommended as first-line prevention of bites from Diptera (includes mosquitos), chiggers, fleas, and ticks in children older than 2 months and in adults. Oil of lemon eucalyptus is recognized as an alternative to DEET by the Environmental Protection Agency (EPA). It is recommended to look for EPA-registered products for ideal efficacy, usually at concentrations of 10% to 40%.

Scabies is a rash caused by the mite Sarcoptes scabiei. Symptoms may not occur for up to 6 weeks after exposure, allowing time for close contacts to become infected as well. It is typically acquired from prolonged skin-to-skin contact (eg, 20 minutes). Scabies is often intensely pruritic and may be found around skin creases. Household contacts with similar symptoms increase the probability of the diagnosis. Dermoscopy and the adhesive tape test have similar negative predictive values for scabies. For the adhesive tape test, transparent tape is applied and rapidly removed from the rash. It is then viewed on 40´ magnification by microscope to identify any mites or eggs. Permethrin 5% topical cream is first-line treatment, with an initial application for approximately 8 hours (often overnight) and another application a week later. It is recommended to wash bedding and clothes in high heat. In adults, scabies may be sexually transmitted; therefore, it is recommended to evaluate and empirically treat sexual contacts.

Ticks may be found still attached to the skin. Prompt removal is recommended by grasping the tick with tweezers (or gloves or a cloth—anything with the exception of bare hands) and gently pulling straight upward, as detailed in this AFP patient handout. The Infectious Diseases Society of America recommends antibiotic prophylaxis against Lyme disease for patients meeting all three criteria: (1) tick has been embedded for ≥ 36 hours; (2) an Ixodes subspecies tick is identified; and (3) the bite occurred in a highly endemic area. Tips for preventing tick bites include tucking pants into socks and wearing boots and light-colored clothing (to make it easier to see ticks) in endemic areas, as well as regular evaluation for ticks following exposure.