What differences should you look for?
| Clue | Bug bites or stings | Poison ivy |
|---|---|---|
| Appearance | One or more raised bumps, sometimes grouped together, with a mark or central blister. | Commonly a red, itchy rash with blisters; swelling can also occur. |
| Sensation | Bites often itch intensely. Stings commonly cause pain, redness and swelling. | An allergic contact rash generally itches more than it hurts. |
| Timing | Some bite bumps fade within hours; others persist for days. | The rash rarely appears immediately and can develop several days after exposure. |
| Exposure | Insects encountered outdoors or an insect you noticed biting or stinging. | Contact with oil from poison ivy, poison oak or poison sumac. |
Gardens and forests are insect habitats, so the scenery comes with residents. Being outdoors does not settle the question: think about whether you touched plants, noticed an insect, or found an attached tick. On brown or black skin, redness around a bite can be harder to see, so also check for a raised lump.13
What should you do now?
- 1Remove anything still attached. Scrape a visible stinger sideways with a fingernail or card edge rather than squeezing it with tweezers. For a tick, use fine tipped tweezers, grasp close to the skin and pull slowly upwards without squeezing.
- 2Clean gently. Wash a bite with soap and water. For a rash, use a gentle cleanser and warm rather than hot water, then pat dry. Avoid scrubbing.
- 3Cool the area. A cool compress can soothe a rash. For a swollen bite, use a cloth wrapped ice pack or cold wet cloth for at least 20 minutes, and raise the area if possible.
- 4Choose itch relief. Calamine can soothe poison ivy and insect bites. Nonprescription 1% hydrocortisone can soothe many rashes, and hydrocortisone cream can reduce bite itching and swelling. Oral antihistamines can help itching; a pharmacist can help you choose a treatment.
- 5Avoid further irritation. Do not scratch bites, because scratching can cause sores and infection. Stop recently added cosmetics or lotions, and avoid applying cosmetic products directly to the rash.
How long should you wait?
Ordinary insect bites and stings usually improve within a few days. Get medical advice if symptoms worsen or home treatment is not helping. For a rash of uncertain cause, arrange an assessment if it remains after a week of treatment rather than continuing to guess from its appearance.356
When does it need medical attention?
Call your local emergency number for trouble breathing, throat tightness, sudden swelling of the face, lips or tongue, or collapse. Seek prompt medical advice for severe pain, fever, pus, increasing warmth, red streaks, or blisters around the eyes, mouth or genitals. A possible tick bite needs assessment, particularly with flu like symptoms or a round rash resembling a bullseye. A baby under 1 year with a bite or sting should see a doctor.356
What if the cause is still unclear?
A clinician can examine the rash and review your exposures. Repeated itchy rashes can warrant patch testing for contact allergies. Unlike a skin prick test for immediate reactions, patch testing checks delayed skin reactions, with follow up readings because allergies can take days to appear.57
How can you reduce another exposure?
Mosquitoes are attracted to heat and exhaled carbon dioxide, so their guest list requires very little paperwork. Wear covering clothing in wooded areas, avoid touching unknown plants, and use insect repellent containing at least 20% DEET. Repellent addresses insects; avoiding plant contact addresses poison ivy.14
Where this answer comes from
- 1Arthropod bites and stingsdermnetnz.org
- 2Poison ivy, oak, and sumacaad.org
- 3Insect bites and stingsnhs.uk
- 4Poisonous vs. Venomous: What’s the Difference?health.clevelandclinic.org
- 5Rash Evaluation: MedlinePlus Medical Testmedlineplus.gov
- 6Rashes: MedlinePlus Medical Encyclopediamedlineplus.gov
- 7Patch testing can find what's causing your rashaad.org
