A Quick Guide to Common Insect Bites

• Mosquitoes: The most common symptom is raised red or pink itchy bumps. They can itch for three or four days, and they typically fade within a week. Mosquitoes are most active at dawn and dusk.
• Ticks: Ticks can be smaller than a sesame seed and hard to spot, so you may not know you were bitten by one until you have symptoms. Check your skin after being outside in wooded areas or walking in tall grass, where ticks are often found. Typical tick bite sites are under the arms, around the ears and on the back of the knees, but ticks can bite anywhere. Watch for a bull’s‑eye rash or fever. If you do get bitten and see the tick, learn how to remove a tick safely.
• Bees, wasps and hornets: Sometimes you can see a visible stinger. You can have redness and pain that lasts one to two hours after the sting, and swelling and itching near the sting site for a couple of days.
• Fire ants: Immediately after a sting, you can have burning and pain near the site. Within 24 hours, you can develop redness, itching and white, fluid-filled blisters. These symptoms may last for up to 10 days.
• Spiders: Most spider bites don’t go all the way through the skin, are mild and go away within a week. A bite can show up as a raised red bump, and you can have redness, pain and swelling near the bite site.
• Bites from venomous widow spiders (like black widows) need immediate medical attention if severe pain, cramping or sweating occurs.
• A brown recluse spider bite can cause pain and swelling. You may develop a bull’s-eye pattern with a white blister and surrounding redness. This can become an ulcer that can take weeks to heal.
• Bed bugs: These tiny, brownish insects dwell within mattress seams. Their bites appear as small, itchy red bumps in a line or cluster, and can itch for days. It may take two weeks for the red welts to fully go away. 
• Stink bugs: These insects rarely bite humans. If they do, they can cause mild skin reactions like itching and swelling that can last for up to a week.
• Scabies: Scabies mites are microscopic, so you can’t see them. But two to six weeks after you’re exposed, you can have intense itching that worsens at night accompanied by a pimple-like rash and tiny burrow marks in your skin. Symptoms typically appear between fingers, on wrists and under armpits. A skin scraping that looks for mites and eggs under a microscope can help diagnose scabies.

Common Treatments for Bug Bites

At-home treatments

• Wash the bite or sting site with soap and water.
• Alternate applying a cold pack for 10 minutes on, 10 minutes off on the first day of a bite or sting.
• Elevate the area if swollen.
• For itching, use over‑the‑counter hydrocortisone or oral antihistamines.
• For wasp stings (bees don’t leave stingers), remove the stinger by scraping it with a card, such as a credit card or driver’s license.

“Try not to pick or scratch a bite or squeeze a stinger,” says Victoria Catherine Weston, MD, an Emergency Medicine and Immediate Care physician at Northwestern Medicine. “If you feel comfortable removing a tick with tweezers or a wasp stinger with a card, you can do so. Or your doctor can do it for you.”

Over-the-counter treatments

Over-the-counter treatments, available at your local pharmacy without a prescription, can help with mild itching and swelling. If there are signs of infection or an allergic reaction, get medical care right away.

Which Bites Are Most Likely To Cause Serious Reactions?

• Bee, wasp or fire ant stings can trigger life‑threatening allergic reactions.
• Venomous widow spiders, including the black widow, can cause severe pain and muscle symptoms.
• Certain types of ticks can transmit Lyme disease or Rocky Mountain spotted fever. Concerning signs include a bull’s‑eye rash after a tick bite, which can indicate possible Lyme disease or a spreading rash with fever, which can indicate possible Rocky Mountain spotted fever.
• Mosquitoes can spread borne diseases, such as West Nile Virus and Zika.

When To See a Doctor

See a doctor if the skin reactions around a bite get worse after 48 hours, or if there is:

• Warmth near the area of the bite
• Increasing pain
• Pus
• Red streaks
• Fever
• Swollen lymph nodes

These may be signs of cellulitis (a serious bacterial infection that affects the skin’s deep layers) or another infection.

If you have symptoms of scabies, you will need to see a doctor for treatment with prescription medication. All household members, regardless of symptoms, will also need treatment to contain possible spread. Your doctor can advise on treating bedding and other household items to get rid of mites and eggs.

Symptoms That Need Medical Attention Right Away

Call 911 or go straight to the emergency department for severe allergic reactions after a bug bite or sting, including:

• Trouble breathing
• Wheezing
• Chest tightness
• Swelling of the lips, face, throat or tongue
• Fast‑spreading hives
• Dizziness
• Fainting or feeling faint

Severe allergic reactions can happen within minutes after:

• A bee sting
• A wasp sting
• A fire ant sting
• A severe spider bite

If you notice any of these signs, don’t wait to see if symptoms improve.

"If you have a known severe allergy or history of anaphylaxis to bee stings and you get stung, use your epinephrine auto‑injector if you were prescribed one and seek care in the emergency department,” says Dr. Weston.

Additionally, call 911 or go to the emergency department for any of the following symptoms for these bug bites:

• Venomous spider bites (especially from widow spiders like the black widow)
  
• Severe pain
• Cramping
• Sweating
• Nausea
• Vomiting
• Muscle rigidity

• Tick bites
  
• High fever
• Severe headache
• Stiff neck
• Confusion
• A rash with fever

Before You Go to the Emergency Department

Make note of when and where the bite or sting happened. You can also take a photo of the insect or bring it in a sealed container, but it’s not required.

“We no longer routinely send insects to the lab for analysis, but you are welcome to bring the insect in if it is safe to do so and won't result in you receiving any additional stings or bites,” says Dr. Weston.

Dr. Weston says you can use a cold pack and consider using hydrocortisone or an antihistamine for itching. Don’t give antihistamines to babies or take them if you’re older than 65 (unless approved by your doctor). Also, don’t apply hydrocortisone to your face or around your eyes.

Who Is at Higher Risk for Complications?

Groups that are most at risk for complications from bug bites include:

• Children
• Older adults
• People with asthma or prior severe allergic reactions
• People who are pregnant
• People with diabetes, heart disease or weakened immune systems

Simple Steps That Prevent Bug Bites

One way to help prevent bug bites is to apply insect repellent during peak times outdoors. Use an insect repellent that is registered with the Environmental Protection Agency. Examples of insect repellent include DEET, picaridin and oil of lemon eucalyptus.

Apply them according to label directions. Never apply insect repellent to a child’s hands, eyes or mouth, and do not use oil of lemon eucalyptus on children younger than age 3.

You can also:

• Wear long sleeves and pants in wooded areas, and tuck pants into tall socks.
• Do a full‑body tick check after time outdoors.
• Use window screens on your windows or mosquito netting if you’re outside.
• Remove standing water.
• Consider permethrin‑treated clothing, such as pants, socks and boots. Permethrin repels certain types of insects like mosquitoes, and it lasts even after multiple washings.
• Plan outdoor activities when biting insects are less active.
• Cover your cups and drinks with a lid or napkin when outdoors to prevent bees and other bugs from landing in them.
• Check your pets for ticks and other bugs.
• For bed bugs, clean bedding on high heat. Always inspect mattress seams for bed bugs before sleeping on a bed that’s not your own. If you see bed bugs, ask to change rooms. “Anyone can get bed bugs, even at nice hotels,” says Dr. Weston.