Bites & Stings

Bites and stings: treat the reaction, investigate the cause

Skin marks are often ambiguous. Use simple first aid for mild reactions and take severe or worsening symptoms seriously.

Reviewed September 15, 2026

For a simple mosquito-type bite

CDC guidance for mosquito bites includes washing with soap and water and using a cold pack to reduce swelling and itching. Avoid aggressive scratching, which can damage skin.

Why the skin mark may not identify the pest

Many insects and non-insect conditions can produce itchy red bumps. Bed bugs, fleas, mosquitoes, mites, contact dermatitis and other causes can overlap visually. Use environmental clues — where you were, what you found, and whether other people are affected — rather than the bite shape alone.

When to contact a clinician

  • Symptoms are worsening rather than settling.
  • The area becomes increasingly painful, hot, draining or otherwise looks infected.
  • You develop fever or feel systemically unwell.
  • There is significant swelling, eye involvement, or a reaction after a sting.
  • You are unsure whether the bite or sting came from a medically important species in your area.

About anti-itch products

Over-the-counter products differ by active ingredient, age limits, skin condition and country. Read the label and ask a pharmacist or clinician when uncertain, especially for children, pregnancy, broken skin or medication interactions.

Environmental clues are more useful than bite patterns

ClueWhat it may suggestWhy it is not proof
Bites mainly after sleepPossible bed bugs, mosquitoes or other exposureSkin reactions vary and may appear later
Bites around ankles with pets presentFleas are one possibilityOther insects and dermatitis can look similar
Immediate pain after outdoor stingBee/wasp or another stinging insectThe insect itself is the better identifier
Itchy bump after outdoor eveningMosquito is commonMany biting insects overlap

Avoid secondary injury

Scratching can break skin and increase infection risk. Keep the area clean, use a cold pack for swelling when appropriate, and choose any over-the-counter treatment according to its label. Do not apply household pesticides, concentrated essential oils or improvised chemicals to skin.

Primary sources

Key safety and evidence claims on this page are grounded in authoritative public sources. Links open the original guidance.