The eyes are a very sensitive part of the body. A tiny eyelash or particle of sand in the eye can be maddening.

Swelling of the eyelid and the area around the eye is common because of how thin the tissue is. Redness and inflammation are typical reactions to anything that irritates the eye — even insect bites.

If you wake up one day with a sore, swollen, or red eye, it can be tricky to figure out what happened. There are some clues when it comes to insect bites, particularly those from spiders.

Find out how to tell the difference between a spider bite and infections that could cause your eyelid to swell.

If you think you’ve been bitten on the eyelid by a spider, you might want to see what kind of spiders live in your area.

Most of the 3,000 types of spiders in the United States are not dangerous. However, the brown recluse spider is widespread and well-known to cause severe reactions.

The brown recluse and black widow pose a threat to people and pets in North America. Their venom has the ability to cause local reactions at the site of the bite, as well as severe symptoms that affect your entire body.

While there’s no substitute for emergency medical care for these kinds of bites, you can try to reduce symptoms while you seek help by:

  • washing the area immediately
  • applying a cool rag, also known as a cold compress, or ice pack

If you suspect a bug bit you on your eyelid, it can be difficult to tell the kind of bug by the bite alone.

Doctors may look for something called the “eyelid sign.” This is when you have a red, swollen upper eyelid. Sometimes both eyelids are swollen. This reaction is typical of bites from arthropods, or insects with multiple paired legs like spiders and bedbugs.

Mosquito bites are the most common bugs to bite the eyelids. Unless you saw a spider in the area where you were when you were bit, it can be difficult to say exactly what kind of insect — or even arthropod — took a nibble.

Below are a couple of images of the effects of insect bites on the eyelids. A spider bite can be difficult to distinguish from other insects.

With most spider bites, including some minor bites from more dangerous spiders, symptoms are usually limited to the area around the bite. These symptoms can include:

  • burning
  • itching
  • swelling
  • redness or purple discoloration
  • ulcers
  • blisters

Additionally, spider bites and other types of bug bites on the eye usually only affect one eye at a time.

Medical emergency

Seek medical attention right away if you’re having symptoms that are affecting your entire body (called systemic symptoms), or if you’ve seen a brown recluse or other dangerous spider in the area where you were when you were bit. Typically, only venomous spiders cause systemic reactions.

Home treatments for simple insect or spider bites usually focus on reducing swelling by washing the area well and applying a cold pack. You may need additional medical care for more severe reactions or if the bite is affecting your vision.

Corticosteroids and antibiotics may be used with a doctor’s permission to treat spider bites on the eye or eyelid.

Warning

Do not use corticosteroids or antibiotic creams or ointment around the eye unless prescribed by your doctor.

If you can confirm you were bitten by a venomous spider, you may also require an antivenom. In rare cases, bites can turn necrotic, killing healthy tissue. If a spider bite advances to this point, surgery or other invasive treatments may be necessary.

You should seek medical care immediately if you have symptoms that affect your entire body — also called a systemic reaction. While a bite from any spider on the eyelid can hurt or cause swelling, a systemic reaction can be much more dangerous.

Systemic symptoms of a spider bite may include:

  • nausea
  • tiredness
  • weakness
  • vomiting
  • pain throughout your body
  • cramping
  • headache
  • dizziness

Again, these reactions are most common in venomous spiders like the:

Many things can cause a swollen eyelid. If you have swelling in just one eye or have found a spider in the area where you were bitten, it’s safe to assume a spider or similar bug is to blame.

In most cases, spider bites are not caused by dangerous spiders, and an ice pack and maybe some pain medication should be enough to help you recover. If you have trouble seeing or have full-body symptoms, get emergency medical care immediately.