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8 Bug Bites That Might Need Medical Attention—Now

Most bug bites are perfectly harmless—unless these symptoms sound familiar. Go to see your doctor right away if they're familiar.

When the bugs bite, when the bees sting

Once you identify the type of bug bite you need to determine the best way to treat the bite. For some, that might mean seeking out medical attention depending on the severity and type of symptoms. Here’s everything experts want you to keep in mind about these types of bites—including when you shouldn’t brush them off.

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Mosquito bites on their own aren’t a huge deal, but mosquitoes can pass on two potentially serious illnesses: West Nile Virus and Zika. “In the United States, we see more West Nile Virus than Zika,” says Nicholas E. Kman, MD, emergency medicine physician at The Ohio State University Wexner Medical Center. “About 80 percent of people who are infected with West Nile Virus do not feel sick. For people who do, symptoms can include fever, headache, tiredness, nausea, vomiting, swollen lymph glands, and a rash on the chest, stomach, or back.” Symptoms usually last from a few days to a few weeks, according to Dr. Kman. “Some people can get serious infections like encephalitis (an infection of the brain),” he says. “With Zika, the CDC guidelines state that women should wait eight weeks, and men should wait six months after travel or symptomatic infection before attempting to conceive.”

Red blisters on a girl's legs after ants bite (Solenopsis geminata ,tropical fire ant ).Arlee.P/Shutterstock

Fire ants

These vicious biters can produce red, blistered stings in clusters. “Fire ants characteristically bite to attach themselves to their victim and then sting multiple times in a semicircular pattern,” says Carah Santos, MD, pediatric allergist at National Jewish Health. “Simultaneous stings from otherwise non-poisonous insects such as fire ants can result in a toxic reaction—headache, weakness, lightheadedness, drowsiness, fever, diarrhea, muscle spasms, fainting, or seizures. These symptoms require immediate medical attention.” Also, if you develop symptoms of an allergic reaction, such as difficulty breathing, hives, stomach cramps, nausea, diarrhea, or dizziness, head to the ER. Read how this diabetic woman nearly lost her leg from an ant bite.

Robert D Brozek/Shutterstock

Brown recluse spider

As the name suggests, these spiders tend to hide away from the world and won’t bite unless they feel they’re in danger—and often, the bites are painless until several hours after they occur, when it develops a red bullseye look and then begins to blister and turn blue or black. “If the skin is warm, hot, blistering, or sloughing, go to your ER,” Dr. Kman says. “If urine becomes dark, you develop fever, chills, or seizures, this can be the sign of a systemic infection.” Know the other bug bite symptoms you shouldn’t ignore.

Tick Ixodes ricinus on human skin. tick wandering over human hand. Encephalitis tick. This kind of animal is a spreader of borrelia and tbe.Sharomka/Shutterstock


Tick bites themselves aren’t dangerous, but they can put you at risk for a host of serious illnesses, including Lyme disease and Rocky Mountain spotted fever, says Heather Hawthorne, MD, a family practice physician at Doctor On Demand. One trick to limiting the potential damage is catching the bite early. “The risk of getting an infection from a tick bite increases the longer a tick is attached to your skin,” she says. “See a doctor if you suspect a tick was attached more than 24 hours, a spreading rash appears, or you develop fever, muscle aches, headache, nausea, abdominal pain or other flu-like symptoms. Seek emergency care if you develop trouble breathing, heart palpitations, or a severe headache.”

Even if you don’t experience severe symptoms, you may want to see a doctor. “It’s never a bad idea to chat with a doctor if you are worried about a tick bite. A doctor can look at the bite, determine your risk for developing an infection, and in some cases prescribe an antibiotic to prevent Lyme disease if indicated.”

bee sting on the skin. macroschankz/Shutterstock


For most people, bee stings are just a bit of a pain. But certain post-sting symptoms mean it’s time to head for the ER. “After being stung by an insect, such as a bee, wasp, yellow jacket, or hornet, you should immediately call 911 if you develop difficulting breathing, dizziness, stomach cramps, nausea, diarrhea, itchiness, progressive hives, or swelling of the face, tongue, or throat, as these are symptoms of a systemic allergic reaction,” Dr. Santos says. “If you have a severe allergic reaction, it’s also a good idea to ask your doctor if allergy shots can reduce your risk of severe reactions with future stings.”

Species Latrodectus mactans. Black widow spider. Sharon Keating/Shutterstock

Black widow spider

These venomous spiders have an unmistakable red hourglass marking—and the potential to cause serious damage. It’s best to visit a doctor for these bites. “If bitten by a black widow, uncontrolled blood pressure spikes, muscle spasms, seizures, and facial spasms require treatment in an ER,” Dr. Kman says. “Infants or the elderly should get medical attention as the bites can be worse, especially black widow bites.”

A species of Scorpion native to Arizona, called the Giant Hairy, crawling on the back of my hand.Deep Desert Photography/Shutterstock


Scorpion stings usually result in localized pain, swelling, and redness. “If you experience anything more severe than this, then you should seek medical help right away,” Dr. Hawthorne says. “Children and elderly adults should be evaluated by a doctor right away for all scorpion stings, especially if you suspect a bark scorpion sting, which is found in the desert Southwest. Call a doctor, call Poison Control, or get to an ER for an evaluation. Children are at the greatest risk of developing severe symptoms after a sting. Symptoms can progress rapidly, so they need close supervision.”

Puss caterpillar

These caterpillars may look cute and cuddly, but that “fur” is actually a series of poisonous spikes. They’re one of the “harmless” bugs you didn’t know could bite you. For most tangles with the puss caterpillar, the first aid can take place at home. “Apply tape to your skin and pull it off repeatedly to remove the spines, wash the area with soap and water, then apply an ice pack wrapped in a cloth to manage the pain,” Dr. Hawthorne suggests. “Speak with a doctor if the pain persists, rash spreads, skin blisters badly, or fevers develop. Also, see your doctor if you are not up to date on your tetanus booster. Get emergency medical care if severe symptoms develop such as swelling, nausea, difficulty breathing, chest pain, dizziness, headache, or fever.” Next, find out how to identify these 9 common bug bites.

Medically reviewed by Elizabeth Bahar Houshmand, MD, on March 08, 2021

Lisa Milbrand
Lisa Milbrand is a writer and editor from New Jersey, who specializes in health, parenting, and travel topics. She is the author of the upcoming book, Baby Names With Character.