Overview

Insect and spider bites often cause minor swelling, redness, pain, and itching. These mild reactions are common. They may last from a few hours to a few days. Home treatment is often all that's needed to relieve the symptoms of a mild reaction to common stinging or biting spiders and insects, such as fleas, flies, and mosquitoes.

Some people have more severe reactions to bites or stings. Babies and children may be more affected than adults are.

Examples of problems that are more serious include:

• A severe allergic reaction (anaphylaxis). These reactions aren't common. But they can be life-threatening and require emergency care. They may cause:
  • Shock. This can occur if the circulatory system can't get enough blood to the vital organs.
  • Coughing, wheezing, trouble breathing, or a feeling of fullness in the mouth or throat.
  • Swelling of the lips, tongue, ears, eyelids, palms of the hands, soles of the feet, and mucous membranes (angioedema).
  • Lightheadedness and confusion.
  • Belly pain, nausea, vomiting, or diarrhea.
  • Raised, red, itchy bumps called hives and red skin. These symptoms often occur with other symptoms of a severe reaction.
• A toxic reaction to a single sting or bite. Spiders or insects that may cause this include:
  • Black widow spiders.
  • Brown recluse spiders.
  • Scorpions.
  • Puss caterpillars (woolly slugs).
• A toxic reaction to multiple stings or bites from a bee, wasp, or fire ant.
  • A bee leaves its stinger behind and then dies after stinging. Africanized honeybees, the so-called killer bees, are more aggressive than common honeybees. They often attack together in great numbers. Reaction to bee stings can range from minor skin swelling and redness to a serious allergic reaction.
  • Wasps, including hornets and yellow jackets, can sting over and over.
  • A fire ant is a wingless insect. It attaches to a person by biting with its jaws. Then, pivoting its head, it stings from its belly in a circular pattern at multiple sites.
• A large skin reaction with swelling and redness that spreads away from the site of the bite or sting. It may be as large as swelling across two major joints, such as from the elbow to the shoulder.
• A skin infection at the site of the bite or sting.
• Serum sickness. This is a reaction to the medicines (antiserum) used to treat a bite or sting. It may cause hives and flu-like symptoms, such as a fever, muscle aches, or a headache about 3 to 21 days after the use of antiserum.
• A virus infection. Infected mosquitoes can spread the West Nile virus to people, causing an inflammation of the brain (encephalitis).
• A parasite infection. Infected mosquitoes can spread malaria.

Common insects and spiders

Insects that cause mild reactions include:

• Bedbugs.
• Kissing bugs.
• Chiggers.
• Fleas.
• Flies.
• Mites.
• Mosquitoes.
• Nonpoisonous spiders.
• Ticks.
• Scabies.
• Lice.

Some insects are more likely than others to cause allergic or toxic reactions.

• A bee leaves its stinger behind and then dies after stinging. Africanized honeybees, the so-called killer bees, are more aggressive than common honeybees and often attack together in great numbers. Reaction to bee stings can range from minor skin swelling and redness to a serious allergic reaction.
• Wasps, including hornets and yellow jackets, can sting over and over. Yellow jackets cause the greatest number of allergic reactions.
• A fire ant attaches to a person by biting with its jaws. Then, pivoting its head, it stings from its abdomen in a circular pattern at multiple sites.

Self-Care

Caring for an insect bite or sting

Most bites and stings will heal on their own. Here are some things you can do at home.

• Get away from the insect.

  Move away from the stinging or biting insect. Bees will alert other bees, making them more likely to sting.

• Stay as calm and quiet as you can.

  Movement makes venom spread faster in the bloodstream.

• Remove the stinger or spine.

  If you were stung by a bee and the stinger is still in the skin, remove the stinger as soon as you can.

  After contact with a puss caterpillar, remove broken-off spines. Do this by placing cellophane tape or commercial facial peel over the area of the contact and pulling it off.

  If you were stung by a scorpion, see a doctor right away. There is now a medicine (antidote) for scorpion stings.

• Try cold, then heat.
  • Apply an ice pack to a bite or sting for 15 to 20 minutes once an hour for the first 6 hours. When you're not using ice, keep a cool, wet cloth on the bite or sting for up to 6 hours. Always keep a cloth between your skin and the ice pack. Don't apply ice for longer than 15 to 20 minutes at a time. Don't fall asleep with the ice on your skin.
  • After the first 6 hours, if you don't have swelling, try applying warmth to the site for comfort.
• Try a nonprescription medicine to relieve itching, redness, and swelling.
  • An antihistamine that you take by mouth, such as fexofenadine (Allegra) or loratadine (Claritin), may help relieve itching, redness, and swelling.
  • A spray of local anesthetic containing benzocaine, such as Solarcaine, may help relieve pain. If your skin reacts to the spray, stop using it.
  • Hydrocortisone 1% cream or calamine lotion applied to the skin may help relieve itching and redness. You may need to check with your doctor first if you need to use the cream for a child younger than age 2 or for use in the genital area.

  These medicines may not be safe for young children or for people who have certain health problems. Before you use them, check the label. If you do use these medicines, always follow the directions about how much to use based on age and, in some cases, weight. You may need to check with your doctor about using these medicines.

• Try other remedies.

  Some people try a home remedy, such as putting witch hazel or underarm deodorant on the bite. Home remedies haven't been proven scientifically to help. But they usually won't hurt you if you want to try them.

• Watch for signs of a skin infection.

  Signs of infection include:

  • Increased pain, swelling, redness, or warmth around the bite.
  • Red streaks leading from the bite.
  • Pus draining from the bite.
  • A fever.
• Prevent infection.
  • Wash the area with clean water 2 times a day.
  • Don't break any blisters that develop.
  • Try not to scratch the bite area. Trim fingernails to prevent scratching and infection.
  • Apply a bandage, if needed. You may cover the area with a thin layer of petroleum jelly, such as Vaseline, and a nonstick bandage. Apply more petroleum jelly and replace the bandage as needed.

Caring for a spider bite or scorpion sting

• Put ice or a cold pack on the area for 10 to 20 minutes at a time. Put a thin cloth between the ice and your skin.
• Try an over-the-counter medicine for itching, redness, swelling, and pain. Be safe with medicines. Read and follow all instructions on the label.
  • Take an over-the-counter antihistamine to help calm the itching or swelling.
  • Put a hydrocortisone 1% cream or calamine lotion on the skin.
• Don't scratch or rub the skin around the area.

When to call for help during self-care

Call a doctor if any of the following occur during self-care at home:

• New or worse signs of an infection, such as redness, warmth, swelling, or pus.
• Flu-like symptoms, such as a fever, muscle aches, or chills.
• Symptoms occur more often or are more severe.

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