Doctor explaining how to identify spider bites

Arachnophobia, or fear of spiders, is one of the most common phobias around the world. But despite scaring people, the majority of the 3,000 species of spiders will cause no harm to humans.

Most common spiders have fangs that are either too short or too fragile to break through human skin. Often, their venom is not poisonous enough to cause damage.

Common Spider Bite Symptoms

The most common spider bite symptoms include:

  • Small itchy bumps.
  • Irritated skin around bite.
  • Clears up in a few days.

There are two specific spiders in the United States – the brown recluse and the black widow – that can cause serious and even fatal illnesses. It is important to be able to identify these spider bites in order to seek proper treatment.

Can a spider bite cause a rash?

Common spider bites should not cause an additional rash, but the skin around the bite may become irritated and dry. Consult your health care provider if these symptoms continue as they should only last a few days.

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How to Identify a Spider Bite

Common spider bites can look similar to other skin sores, such as bacterial infections. Most spiders only bite when provoked, so you might see the bite as it happens. If you did not see a spider bite you, the usual bite places to check are your hands, ankles, chest, or back.

Brown Recluse Spider Bite Symptoms

The brown recluse spider is usually found in warm, dry climates. Nicknamed the violin spider because of the violin-shaped splotch on its upper back, this spider is nonaggressive and prefers to hide away in dark, undisturbed areas like closets or basements. However, if it feels threatened, the brown recluse will attack.

The initial bite is usually painless but within 8 hours you may notice:

  • Burning, pain, itching, or redness at the site.
  • A red or purple ring around the bite, resembling a target.
  • A fluid-filled blister, which may turn into a deep, enlarging ulcer.

Brown recluse spider bite symptoms may include:

  • Headache.
  • Fever.
  • Chills.
  • Nausea or vomiting.

On rare occasions, symptoms can be as severe as:

  • Coma.
  • Blood in urine.
  • Jaundice.
  • Kidney failure.
  • Seizures.

Death is also a rare result of brown recluse spider bites and is more common with children.

Black Widow Spider Bite Symptoms

Shiny and black with a noticeable reddish hour-glass mark on its belly, the black widow spider is poisonous to humans. Found mostly in warm southern and western states, this spider likes to hide in secluded areas, like barns and woodpiles.

Black widow spider bites usually feel like a pinprick, but may feel like nothing at all. The bite can be identified by:

  • Immediate swelling or redness at the site.
  • Two puncture marks on the skin from the spider’s fangs.

Black widow spider venom is toxic and can cause damage to the nervous system. Symptoms of black widow spider bites may include:

  • Difficulty breathing.
  • Severe muscle cramps.
  • Headache.
  • High blood pressure.
  • Increased salivation and sweating.
  • Muscle weakness.
  • Nausea and vomiting.
  • Numbness.
  • Restlessness.

In rare cases, bites can result in death – mostly in children, the extremely ill, and the elderly.

Treatment for brown recluse spider bites

Unlike common house spider or wood spider bites, brown recluse spider bites may require treatment from a health care provider. The venom can damage tissue surrounding the bite and may cause complications, such as:

  • Scarring.
  • Tissue death.

First aid treatment for brown recluse spider bites should focus on keeping the affected area clean and protected. If blistering or a bull’s eye-shaped wound develops, visit an urgent care facility immediately.

Your provider will examine the brown recluse spider bite and prescribe antibiotics to prevent infection. In extreme cases, such as in cases of tissue death, surgery and hospitalization may be required.

If you think you’ve been bitten by a brown recluse spider, contact the Pittsburgh Poison Center at 1-800-222-1222.

Treatment for black widow spider bites

Black widow spider bites require immediate medical attention. If you think you have a black widow spider bite and are having trouble breathing or experiencing full-body symptoms, such as shock, call 911. You may need immediate medical transport depending on the severity of your symptoms.

If you’ve been bitten, visit an emergency department at your local hospital to seek treatment for your spider bite. On the way, ice the affected area to treat symptoms of swelling and pain.

In many cases, your emergency care team may recommend a combination of narcotics and antivenin for pain and symptom relief. Antivenin works to remove black widow spider venom from your body. It can neutralize the venom, halting further damage, but cannot reverse damage already done.

Often, even with narcotics, you may not find relief from your symptoms for quite some time.

If you think you’ve been bitten by a black widow spider, contact the Pittsburgh Poison Center at 1-800-222-1222.

How to Treat a Spider Bite

If you are bitten by a spider you should start by cleaning the wound and applying a cold compress. This will stop the swelling and allow you to assess the wound. Should your symptoms continue or worsen, you may want to seek medical attention.

How to treat a poisonous spider bite

If you or a loved one has been bitten by a brown recluse spider or a black widow spider, you should:

  1. Use antibacterial soap and water to clean the wound and skin around the bite.
  2. Tie a snug bandage above the bite if it is on an arm or leg and elevate the limb to slow or stop the venom’s spread.
  3. Apply a cold cloth to the bite location.
  4. Seek immediate medical attention.

Home remedies for spider bites

In many cases, you can use home remedies for spider bites. Most spider bites require medical attention only if symptoms appear to be life-threatening. For nonvenomous spider bites, you may:

  • Apply a cold compress or ice pack to the bite and elevate the area to relieve swelling.
  • Take an oral antihistamine or use a local anesthetic directly on the bite to help with itching.
  • Regularly clean the area to prevent infection.
  • Apply antibiotic ointment to the infected area if blisters develop.
  • Contact your health care provider if new symptoms develop or if symptoms do not go away over time.

If you or a loved one are bitten by a spider or have an insect bite you can’t quite identify, please seek immediate medical help. You can visit any UPMC Urgent Care center without making an appointment. We’re here to help you get the care you need when you need it most.

When to Worry About a Spider Bite

Symptoms caused by a poisonous spider bite are much worse than those of a common spider bite. You should be worried about a spider bite if you are experiencing severe pain, particularly:

  • Abdominal cramping.
  • Problems breathing or swallowing.
  • Fever or chills.
  • Red streaks spreading from the wound.
  • A growing wound at the bite site.

Editor's Note: This article was originally published on , and was last reviewed on .

About Urgent Care

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