Spider and Insect Bites and Stings: Symptoms and Treatments

Many insect bites and stings are uncomfortable, but few produce truly life-threatening symptoms. Whether from spiders, wasps, ticks, mosquitoes or other venomous insects or arachnids, however, stings and bites commonly trigger itching or pain, and some transmit illness.


Most bites or stings generate only minor skin symptoms such as itching, pain or swelling around the site, according to the Mayo Clinic, as well as burning or tingling.

Delayed effects, which can appear within hours or days, include painful joints, swollen glands, hives or fever. Reactions depend on the type of wound: bites from fire ants and stings from hornets, bees and wasps are usually painful, while bites by mosquitoes, mites and fleas are typically itchy.

Tick bites may be unnoticeable, but those from the tiny black-legged deer tick, which transmits Lyme disease, can result in a circular red lesion known as a bull’s-eye rash, according to the U.S. Food and Drug Administration. Lyme disease bacteria can also cause fever, fatigue, headaches and joint aches.

Most spider bites are harmless and prompt only mild, local skin reactions, though in rare cases they can prove fatal. According to the U.S. Centers for Disease Control (CDC), typical spider bite symptoms include:

  • Raised welt with a pinpoint-sized dot in the center
  • Pain, itching or rash
  • Muscle pain or cramps
  • Profuse sweating
  • Headache
  • Nausea or vomiting
  • Chills and fever

Allergic Reactions

Some people experience a sudden, severe allergic reaction to bites or stings known as anaphylaxis, which can quickly prove fatal and requires emergency care, according to the National Institutes of Health (NIH). Call 911 if reaction signs include:

  • Difficulty breathing or shortness of breath
  • Facial or mouth swelling
  • Abdominal pain or nausea
  • Difficulty swallowing
  • Pale, moist skin that may appear blue
  • Hives
  • Confusion or disorientation
  • Weakness or dizziness
  • Fast, weak pulse

Types of Insects and Spiders that Bite

Many common insects bite without provocation, including mosquitoes, fleas, mites, flies, bedbugs or fire ants. Others sting when feeling threatened, such as wasps, bees and hornets.

Most of the 20,000 spider species found in the United States are poisonous, according to Children’s Hospital of Pittsburgh, but only a couple have fangs long or strong enough to pierce human skin. These include the brown recluse and black widow spiders, whose bites are serious and require emergency attention.

Brown recluse spiders are usually found in Midwestern and Southern states, according to the CDC, and are also called violin spiders because of the characteristic violin- or fiddle-shaped marking on their heads. These spiders have six equal-sized eyes (in contrast to the typical eight) and are about an inch long.

Symptoms of a brown recluse spider bite include:

  • Deep blue or purple area around the bite, surrounded by white and red outer rings
  • Burning, itching, pain or redness that may develop within hours or days
  • Ulcer or blister that turns black
  • Fever
  • Rash
  • Nausea or vomiting

Black widow spiders are usually found in southern and western parts of the United States, though they live throughout North America. Small, black and button-shaped with a characteristic red hourglass marking on the abdomen, black widows release a toxin that can damage the central nervous system.

According to the University of Maryland Medical Center, symptoms of a black widow spider bite include:

  • Double fang marks at the site
  • Immediate pain, swelling, burning and redness
  • Headache and dizziness
  • Rash and itching
  • Cramping and rigidity in the chest, stomach, back and shoulders
  • Anxiety and restlessness
  • Eyelid swelling
  • Weakness or paralysis, particularly in the legs
  • Excess saliva or eye tearing
  • Nausea and vomiting

Care & Treatment

Most bites and stings require only minimal treatment. If a stinger is present, remove it by scraping a credit card or other straight-edged item across the stinger, according to the NIH. Use tweezers only to remove ticks, not stingers, as they may squeeze the venom sack and add to the venom released.

All insect bites and stings should be washed with soap and water. According to the Mayo Clinic, other treatment can include:

  • Applying ice to reduce pain and swelling
  • Applying calamine lotion or hydrocortisone cream for itching and swelling
  • Taking antihistamines containing diphenhydramine (found in the brand names Benadryl or Tylenol Severe Allergy) or chlorpheniramine maleate (in Chlor-Trimeton and Actifed).

All suspected spider bites should receive prompt medical attention, as should any insect bite or sting that produces the severe symptoms listed above. Suspected tick bites should also be seen by a doctor to rule out Lyme disease, which requires antibiotics.

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