Spider Bite: Symptoms & Signs

A spider bite is a skin and tissue injury from the bite of a spider. Most spiders are harmless, but the brown recluse and black widow spiders are two potentially serious causes of spider bites. In some cases, the signs and symptoms of a spider bite may develop without the individual being aware that they have been bitten.

Signs and symptoms of a spider bite can vary depending upon the type of spider involved. Symptoms associated with a spider bite can include pain at the site, redness, blister formation, a small bump on the skin, pimples, itching, swelling, and rash. More serious cases of spider bite may result in muscle pain, cramping, sweating, difficulty breathing, nausea, vomiting, and headache.

Symptoms and signs of spider bites

Common spider bites symptoms include.

  • Bites from most (non-poisonous) spiders cause local redness, irritation, and pain that usually can be treated at home using an over-the-counter pain reliever along with application of cooling packs or a wet cloth to relieve swelling.
  • These local reactions usually resolve without treatment over a period of 7-10 days. Rarely, an individual can have an allergic reaction to a spider bite, even to a bite from a non-poisonous spider, but allergic reactions are more likely to be due to contact with a spider than from a spider bite.

Can black widow or brown recluse spider bite symptoms be the same?

Generalized symptoms of bites from black widow and brown recluse spiders may include:

Rarely, black widow spider bites are fatal; however, a few individuals have died from brown recluse spider bites, which are more common in children than in adults.

If a spider was not observed inflicting the bite, it is difficult if not impossible to determine whether a spider bite occurred, since many conditions of the skin may produce the same symptoms as a spider bite. Streptococcal and Staphylococcal infections, early lesions of herpes simplex or zoster, burns, stings or bites from other arthropods or insects (including fleas, bedbugs, mosquitos, biting flies, ants, and ticks), thorn injury, and early Lyme disease all may be characterized by skin findings similar to those from a spider bite.

Spiders rarely bite people, and only if threatened. People often thing they have spider bites when the irritation is from another cause.

Other spider bite symptoms and signs

IMAGES

Eczema Browse our medical image collection of allergic skin disorders such as psoriasis and dermatitis and more caused by allergies See Images

Subscribe to MedicineNet's Skin Care & Conditions Newsletter

By clicking "Submit," I agree to the MedicineNet Terms and Conditions and Privacy Policy. I also agree to receive emails from MedicineNet and I understand that I may opt out of MedicineNet subscriptions at any time.

Medically Reviewed on 9/10/2019
References
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.