How to care for black widow spider bites

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The black widow spider is identified by a red hourglass marking on the underside of the abdomen and shiny black in color at about 3-10 mm in size. Females are usually larger than males about 13 mm length. The black widow spider prefers dark secluded areas such as woodpiles and crevices. In homes, they can be found in sheltered, dimly lighted areas such as basements, dark corners, cluttered areas and closets. The webs are irregular and messy and usually found near ground level, under lawn furniture or piles of wood.

The spider produces a protein-based venom that targets the nervous system of the individual. Some people can be minimally affected by this venom but some end up with severe reactions. The symptoms usually begin within 20 minutes up to an hour after being bitten.

Symptoms of a black widow spider bite

  • Localized pain with severe muscle cramps, weakness, pain in the abdomen and tremors. The shoulder or back muscles are usually affected by severe pain. If the bite is severe, it causes symptoms such as vomiting, nausea, chest pain, dizziness and respiratory difficulties.
  • The severity of the reaction will depend on the physical condition and age and usually children and older people are seriously affected by the bites.
  • Abdominal pain that has similarities with appendicits or problems with the gallbladder.
  • High blood pressure and increased heart rate
    Black widow spider
    Localized pain with severe muscle cramps, weakness, pain in the abdomen and tremors.
  • Children and old people are prone to severe and dangerous reactions
  • Stiffness, excessive sweating and hypertension
  • Anxiety, restlessness and delirium


  • Clean the affected area using water and soap
  • Apply a cold compress on the bite site. Avoid applying an ice pack directly on the skin to prevent frostbite that can worsen the condition. Wrap the pack with a towel before applying on the area.
  • Apply the prescribed antibiotic cream lotion on the bite site to minimize the risk for infection
  • Elevate the affected area above the level of the heart to prevent swelling.
  • Place the spider in small jar to be examined by an expert if possible.
  • Take the prescribed over-the counter pain medications to numb severe pain. A muscle relaxant can also be given as injections.
  • For a severe bite caused by black widow spider, the affected person is given an antivenin which lessens the symptoms quickly but it causes some side effects such as an allergic reaction and serum sickness. Skin testing is required before an antivenin can be given.


  • Limit the amount of clutter in the workplaces or home. Regular cleaning of the surroundings is important.
  • Avoid growing tall grasses or weeds near the foundations of the house.
  • Keep shoes and gloves in covered containers.

Disclaimer / More Information

The material posted on this page on black widow spider bites is for learning purposes only. Learn to recognize and manage black widow spider bites by taking a first aid and CPR class with one of our training providers.

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