Bites, Arthropod
Definition: Arthropod bites are skin reactions caused by the bite or sting of different arthropods such as arachnids (spiders,ticks), insects (mosquitoes, fleas, and bedbugs), Chilopods (centipedes) and Diplopods (millipedes)(1).
Etiology: The skin reaction is brought on by the entry of venom, saliva, or other compounds from arthropods into the skin, which triggers an inflammatory reaction ( ).
Epidemiology: Arthropod bites are prevalent across the world, especially in warmer climates (1,2). The incidence is higher in those that participate in outdoor activities (1,2).
Signs: At the site of the bite there may be erythematous papules, weals, or vesicles along with surrounding erythema and edema (3).
Symptoms: Burning, local redness discomfort, or localized itching at the bite site (1). Systemic symptoms including fever, headaches, or allergic reactions (i.e. anaphylaxis) can occur in certain people (1).
Differentials: Urticaria, cellulitis, contact dermatitis, drug eruption, mastocytosis bullous disease, dermatitis herpetiformis, tinea, eczema, vasculitis, pityriasis, erythema multiforme, viral exanthem (1).
Diagnosis: Diagnosis is clinical, based on history and clinical findings. A thorough history may be useful to determine the exact arthropod. Diagnostic tests (labs, biopsy and imaging are rarely needed but in some cases may help confirm diagnosis (1).
Treatment: For arthropod stings the stinger should be removed followed by a cold compress, topical steroid cream or calamine lotion (2). Oral antihistamine can be used to reduce the itching sensation and weals (2). Epinephrine for anaphylaxis may be necessary in severe cases (2). Wearing protective clothes and applying insect repellent are the best preventive actions (2).
References: (AMA)
1. Domino FJ, Baldor RA, Golding J, Grimes JA. The 5-Minute Clinical Consult Premium 2015. Wolters Kluwer Health; 2014.
2. Arthropod bites and stings. DermNet®. May 23, 2024. Accessed August 24, 2024. https://dermnetnz.org/topics/arthropod-bites-and-stings.
3. Powers J. Insect bites. StatPearls [Internet]. August 8, 2023. Accessed August 24, 2024. https://www.ncbi.nlm.nih.gov/books/NBK537235/#:~:text=There%20is%20usually%20a%20pruritic,bacterial%20infection%20may%20be%20present.