Bug bites are a fact of life, especially if you spend a lot of time outdoors. While allergies and other factors can lead to serious reactions, most bugs tend to cause mild symptoms like swelling and itchiness.

But depending on the bug and your individual reaction, bruising is possible. Bruising may occur from flying insects and from bugs that can burrow deep into your skin.

Find out more about the types of bugs that may cause bruising, what you should do, and how to identify the most common symptoms associated with certain bugs so you know when to seek medical treatment.

Should I be concerned?

A bruise from a bug bite isn’t usually a cause for concern. Most bug bite symptoms go away on their own within a few days.

However, if you know that a certain type of bug bit you, or if your symptoms worsen, you may need to see a doctor.

Healthline

The following types of bug bites sometimes cause bruising. Here’s what you need to know.

Hornets and wasps

Hornet and wasp stings are often painful.

After the sting occurs, the affected area of skin may be red and swollen. It may also look blue and purple due to the injury.

Such symptoms tend to resolve on their own within a few days without the need to see a doctor.

Mosquitoes

Mosquitoes are perhaps best known for leaving behind small, red bumps that are extremely itchy. Sometimes, these bumps may also darken, creating a bruise-like appearance.

As with hornets and wasps, mosquito bite bruises don’t usually require medical attention.

Spiders

Certain types of spider bites may also lead to bruising, including venomous ones like the brown recluse spider or black widow spider.

With this type of bite, you’ll notice rings around the site in varying colors, including red, blue, purple, and white. This is a result of skin necrosis from the venom, which destroys skin tissue.

Venomous spider bites require immediate medical attention.

Ticks

Ticks burrow deep in the skin, so you must carefully remove them by the head with a pair of tweezers.

When caught early, you may not notice any symptoms. Ticks can sometimes leave behind a red mark or bruise, which can also be swollen and itchy.

Aside from bruising, a bug bite may also cause redness and swelling (inflammation).

Even without a bruise, these symptoms may be present. Some insects, such as mosquitoes, may cause itchy bites.

Most symptoms are minor and will go away within a few days.

Signs of a more serious reaction

It’s possible for a bug bite to cause more serious reactions. Get medical attention right away if you experience signs of anaphylaxis, a serious allergic reaction that can cause:

You should also call your doctor if you experience symptoms of an infected bug bite, including:

  • fever
  • chills
  • pus coming out of the bite
  • swelling that continues to grow without improvement
  • a red streak growing from the bite

A doctor will recommend home treatments to help alleviate mild bug bites. Follow these steps for bug bites with bruising:

  1. First, wash the bug bite with plain soap and warm water. Pat (don’t rub) dry.
  2. Apply cold compresses or ice to the affected area for 15 minutes at a time, multiple times a day. This helps alleviate pain and swelling. Repeat up to 48 hours after the bug bite.
  3. Rest and elevate the affected area, if possible. This can help reduce swelling.
  4. Switch to warm compresses after 48 hours to help reduce pain. Repeat as often as needed.
  5. If your doctor says it’s OK, take a pain reliever such as acetaminophen (Tylenol) or a nonsteroidal anti-inflammatory drug (NSAID) like ibuprofen.
  6. For itchiness, consider a topical hydrocortisone cream or an oral antihistamine such as diphenhydramine (Benadryl). Follow all product directions carefully.

If you have a more serious bug bite, it’s important to get the area checked by your doctor before attempting to self-treat.

If you don’t know what bug you’ve come into contact with, you may be able to make this determination based on the symptoms of your bite.

Here’s a roundup of the most frequent symptoms associated with common bugs in the United States:

BruiseRednessSwellingItchingBumpsColored ringsRash/clustered bitesPain
bed bugxxxx
beexxx x
fleaxxxx
flyxxxx
gnatxxxx
hornet or waspxxxxx x
mosquitoxxxxx
spiderxxxxx
tickxxxxx

Serious bug bites may sometimes lead to the following complications:

  • Infections. Fever, rash, and pus at the site of the bite are all signs of infection. It’s important to quickly address a possible infection such as cellulitis.
  • Lyme disease. Caused by tick bites, early symptoms of Lyme disease can include a fever and a rash that looks like a red bull’s-eye.
  • Necrosis. This can occur in the case of brown recluse spiders, whose venom can kill healthy skin tissue and lead to lasting complications such as scars.
  • Viruses transmitted by mosquitoes. These include the West Nile virus, yellow fever, the Zika virus, and malaria.

A bruise alone may not be a sign of the above complications. That’s why it’s important to see a doctor if:

  • you have a bite that won’t improve
  • you develop symptoms related to a venomous spider or tick

Bruises are caused by broken blood vessels brought on by trauma to the body. The black, blue, or purple areas of skin are a result of blood pooling underneath your skin.

Any type of injury or trauma can lead to a bruise. You might also be at risk for bruising based on:

Minor bruises don’t typically need medical attention. Severe bruising causes by more serious trauma such as car accidents may need to be evaluated for underlying damage.

Other types of bruises that may need further attention include those caused by bone fractures or a bleeding disorder.

Most bruises heal within 2 weeks, though more severe cases can take longer. See a doctor if your bruise doesn’t improve after 4 weeks, as it may be a sign of an underlying condition.

Bruising is just one of the many symptoms of a bug bite and is more common with some insects. Most cases are mild and can be treated at home.

See your doctor or another healthcare provider if you develop a severe reaction to your bug bite, or if the bruising doesn’t improve after several days.

You should also seek medical attention if you suspect a venomous or disease-carrying bug might have caused your bites.