MANUAL MINORS
Insect bites are skin injuries caused by insects such as mosquitoes, bees, wasps, ants, and fleas. They typically provoke a mild local reaction with redness, swelling, itching, or pain at the affected area. However, some bites can trigger severe allergic reactions (anaphylaxis) or transmit diseases like dengue, Zika, or malaria, depending on the insect and geographic region.
Diagnosis
Diagnosis is based on the clinical history of the bite and the appearance of a localised lesion, characterised by swelling, erythema, and pruritus. In cases of severe allergy, the patient may present systemic symptoms such as difficulty breathing, generalised hives, or facial swelling (angioedema). In endemic areas, bites from certain insects can lead to symptoms such as fever, muscle pain, or skin rashes, suggesting vector-borne diseases.
Differential Diagnosis
Condition | Key Difference |
|---|---|
Contact dermatitis | Skin rash from irritants or allergens, unrelated to bites. |
Urticaria | Itchy welts resembling bites, but without insect contact history. |
Cellulitis | Subcutaneous tissue infection causing swelling and pain, not related to bites. |
Allergic reaction to food/drugs | Systemic or local reaction without evidence of an insect bite or contact. |
Emergency Management
Initial management includes cleaning the bite with soap and water and applying topical antihistamines or corticosteroids to reduce itching and inflammation. Oral antihistamines (e.g., diphenhydramine) or nonsteroidal anti-inflammatory drugs (NSAIDs) may be given to control symptoms.
For bee or wasp stings, the stinger should be removed if present, using a flat object like a card, avoiding tweezers to prevent injecting more venom. If the patient shows signs of anaphylaxis (difficulty breathing, angioedema, hypotension), intramuscular adrenaline should be administered immediately, and the patient should be transported to the hospital for advanced management.
Definitive Treatment
For most insect bites, definitive treatment is symptomatic, using antihistamines, topical steroids, and NSAIDs. If a secondary infection occurs, antibiotics may be prescribed. For patients with a history of severe allergic reactions to insect bites, an epinephrine auto-injector should be provided, and they should be educated on its use. In regions where insect bites transmit diseases like dengue or malaria, treatment should target the identified infectious agent, including the use of specific antivirals or antiparasitics as necessary.
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