When to Worry About Bug Bites: Signs You Need a Doctor

Most bug bites are a nuisance, not a danger. Worry when a bite gets more red, painful, warm or swollen after the first couple of days, when it oozes pus or sends a red streak up the skin, or when you get a fever, a bull’s-eye rash, or any trouble breathing. The last of those is a 911 call. Everything else on this page helps you tell which situation you are in.

Justbiteme

Soothe Itching From Bug Bites

Just Bite Me’s natural balm temporarily alleviates irritation and itching from insect bites, including mosquito and chigger bites.

Visit Just Bite Me

TL;DR

Itching, mild swelling and stinging that fade within a day or two are normal and can be handled at home.
Redness, pain or warmth that grows after a couple of days, pus, fluid leaking from the bite, red streaks, or fever point to infection. Call your doctor.
A bull’s-eye rash, fever, headache or joint pain after a tick bite needs a medical evaluation.
Trouble breathing, wheezing, swelling of the face, tongue or throat, dizziness or a weak pulse after a sting means call 911.
Suspected black widow or brown recluse bites need emergency care, even if the bite felt minor.

What a normal bug bite looks like
How to tell if a bug bite is infected
When to see a doctor for an insect bite
Serious symptoms: when to call 911
When to worry about a spider bite
Perspective: why we think about bites the way we do
Keeping bites comfortable while you watch them
Add a natural itch-relief balm to your pack
FAQ
Sources

What a normal bug bite looks like

A typical bite itches, puffs up a little and may sting. According to the Mayo Clinic, most insect bites and stings are mild, can be treated at home, and the symptoms go away in a day or two. Skin redness and itching can last longer than people expect. UK guidance from NICE notes they may continue for up to 10 days, and that most bites and stings do not need antibiotics.

So the first question is not “is this bite red?” but “is it getting better or worse?” A bite that peaks early and then fades is behaving. A bite that looks worse on day three than on day one deserves a closer look.

What you can safely do at home

The basics are the same across the major health sources:

Wash the area with soap and water. MedlinePlus recommends this for mild bites and stings.
Apply a cold cloth or ice for 10 to 20 minutes, per the Mayo Clinic, to calm swelling.
Use calamine, hydrocortisone cream or an oral anti-itch medicine for itching.
Don’t scratch. Broken skin is the most common way a harmless bite turns into an infected one.

If a bee, wasp or hornet stung you, the CDC says to remove the stinger with gauze or by scraping a fingernail across it. Never squeeze it or use tweezers. MedlinePlus adds that you should never apply a tourniquet.

For a step-by-step routine you can pack, see our bug bite first aid guide and family kit. If swelling is the main issue, our five first aid steps for bug bite swelling cover it in more detail.

How to tell if a bug bite is infected

Infection usually shows up a couple of days after the bite, not in the first hours. Mass General Brigham lists worsening redness, pain or warmth, pus, red streaks and fever as the typical signs.

Sign	Normal bite	Possibly infected
Timing	Worst in the first day or two, then fades	Gets worse after two or three days
Redness	Small area around the bite	Spreading outward, or red streaks
Pain	Itchy or mildly sore	Increasingly painful or tender
Skin temperature	Normal	Warm or hot to the touch
Drainage	None, or a little clear weeping from scratching	Pus, or fluid that keeps leaking
Whole body	Feel fine	Fever, chills, nausea, swollen lymph nodes

The Cleveland Clinic describes cellulitis, a skin infection, as a possible result of an infected bite, and notes that fever, chills, nausea and swollen lymph nodes can come with it.

Is clear fluid leaking from a bite normal?

A little clear weeping from a bite you have scratched open is common. But Johns Hopkins Medicine lists fluid leaking from a bite as a possible sign of infection and advises contacting a healthcare provider. If the fluid is cloudy, yellow, or keeps coming, or if the skin around it is also getting redder and sorer, call.

Mild versus worrying: where a pharmacist fits

If a bite is red, a bit warm and slightly swollen, but there is no fever and the redness is not spreading, a pharmacist can often take a look and suggest what to use. Anything with spreading redness, streaks, pus or fever goes to a doctor or urgent care instead.

When to see a doctor for an insect bite

Book an appointment or go to urgent care when any of these apply. They come from the Cleveland Clinic’s bug bite guidance:

Symptoms get worse, or do not start to go away after a few days.
The bite is close to an eye.
You see signs of infection, such as red streaks or pus.
You develop symptoms of an insect-borne illness, which can appear within two weeks of a bite: body aches, chills, fever, joint pain, nausea, vomiting, pain behind the eyes, swollen lymph nodes, or a round rash that looks like a bull’s-eye.

Texas Health also advises a medical visit when fever or chills follow a bite, since they may signal a systemic infection.

Tick bites and Lyme disease

A bull’s-eye rash, fever, headache, neck pain or joint pain after a tick bite may point to Lyme disease, and Mass General Brigham says it should be evaluated by a medical professional. Note the date of the bite and take a photo of any rash as it changes. Both help your clinician. The rash can show up days to weeks later, so a bite you forgot about still counts if these symptoms appear.

Bites near the eye, and bites in kids

A bite or sting close to the eye needs a call to a medical provider rather than a wait-and-see approach. For children, the same signs apply, but kids scratch more and tell you less. Check bites daily for spreading redness, warmth or drainage, keep nails short, and call the pediatrician if your child seems unwell with a fever.

Serious symptoms: when to call 911

Some reactions are not infection at all. They are allergic, and they can move fast. MedlinePlus describes anaphylaxis as a severe, life-threatening allergic reaction that can occur very quickly and needs immediate medical attention.

Call 911 if, after a bite or sting, you or someone else has:

Trouble breathing or wheezing
Swelling of the face, mouth, tongue or throat
Throat tightness or trouble swallowing
Dizziness, feeling faint or weak
A rapid or weak pulse
Nausea and vomiting

These signs are listed by the Mayo Clinic and MedlinePlus. People who have had a serious allergic reaction before should carry epinephrine as their provider instructs, according to MedlinePlus. If you have a prescribed auto-injector, use it as directed and then get emergency care. MedlinePlus also points out that anxiety can make an allergic reaction feel worse, so keep the person calm and reassured while help is on the way.

Which bites cause dizziness?

Dizziness is not tied to one bug. It is a warning sign in several situations. It can be part of an allergic reaction to a bee, wasp, hornet or fire ant sting. The Cleveland Clinic also lists dizziness, nausea, muscle pain and trouble breathing among the reasons to seek care right away. It can also accompany the fever and chills of an insect-borne illness. If you feel dizzy after any bite, sit or lie down, stop the activity, and get medical help, calling 911 if you also have breathing trouble, swelling of the face or throat, or a weak pulse.

Fire ants and multiple stings

A single fire ant sting is usually a local problem, but MedlinePlus notes that multiple stings may lead to severe reactions. In the US, Poison Control can be reached at 1-800-222-1222.

When to worry about a spider bite

Most spider bites in the US are minor. Two are not. The Cleveland Clinic says to seek emergency care if you suspect a black widow or brown recluse bite. MedlinePlus explains that brown recluse venom can destroy skin and cause necrosis, so treatment should not wait.

Research in PubMed Central also notes that some bites, specifically brown recluse, can be painless at first and then progress to severe skin lesions or whole-body illness. A bite that seemed like nothing but turns into a spreading, darkening or blistering wound is worth an urgent visit. If you can safely catch or photograph the spider, do.

Perspective: why we think about bites the way we do

Most of the bug bite questions we hear come down to one thing: people don’t know whether to treat it or watch it. Our answer is that comfort and watchfulness work together. Calm the itch early, so you aren’t scratching the skin open, and look at the bite again the next day.
That is why we made Just Bite Me with five ingredients: beeswax, coconut oil, baking soda, lemongrass oil and wintergreen oil. It is designed to temporarily relieve the irritation and itching of insect bites and minor skin irritations, and it was made with sensitive skin and kids in mind. A balm that is easy to carry and pleasant to use gets applied at the first itch, which is when it counts most.
A balm is for comfort. It does not treat infection, an allergic reaction or tick-borne illness. If you see spreading redness, pus, fever or a bull’s-eye rash, or any breathing trouble, skip the balm and get care. For everything milder, we think a simple, clean formula in your pack is the sensible first move.
Matt

Keeping bites comfortable while you watch them

For a mild bite, the aim is to stop the itch-scratch cycle. Cool it first, then protect the skin. A gentle balm on a clean, unbroken bite can help you resist scratching. Our pages on soothing ingredients for insect bites, calming mosquito bites and stopping itch without drowsiness go through the options. For bee and wasp stings, see how to soothe bee stings at home.

A few habits make a difference:

Wash hands before and after touching a bite.
Keep the bite clean and covered if it is likely to be rubbed or scratched.
Take a photo each day. Comparing pictures is the easiest way to tell whether redness is spreading.
Mark the edge of any red area with a pen. If redness moves past the line, call.

Add a natural itch-relief balm to your pack

If you spend time on trails, at campsites or in the backyard, a compact balm means you can treat the itch right when it starts. Just Bite Me is a five-ingredient bug bite relief balm that temporarily relieves the itching and irritation of insect bites, including mosquitoes and chiggers, and is suitable for sensitive skin and children. See how it works in our five-ingredient trail balm guide.

Tuck it next to your first aid supplies, and keep your doctor’s number and the Poison Control line handy too.

FAQ

How long should a bug bite take to heal?

Most bites fade in a day or two. Redness and itching can linger for up to 10 days, according to NICE. If a bite is getting worse after a few days instead of better, or has not started to improve, have it checked.

What are the first signs of an infected insect bite?

Look for redness that spreads, more pain, warmth, pus, red streaks and fever. These tend to appear a couple of days after the bite. Fever, chills or swollen lymph nodes mean the infection may be affecting your whole body, so call a doctor.

Do I need antibiotics for a bug bite?

Usually not. NICE says most insect bites and stings do not need antibiotics. Only a clinician can tell whether a bite is infected and needs treatment, so see one if you notice signs of infection.

When is a bug bite an emergency?

Call 911 for trouble breathing, wheezing, swelling of the face, tongue or throat, dizziness, a weak or rapid pulse, or vomiting after a bite or sting. Suspected black widow or brown recluse bites also need emergency care.