Toxic Reaction to Insect or Spider Venom

Topic Overview

Bites and stings from insects (bees, wasps, yellow jackets) and spiders usually cause pain, swelling, redness, and itching at the site of the sting or bite. In some people, especially children, the redness and swelling may be worse and last up to a few days.

A few people have severe reactions to the toxin injected by the insect or spider. A toxic reaction occurs when insect or spider venom acts like a poison in the body. This type of reaction can occur from one bite or sting from a highly toxic insect or spider, or from multiple bites or stings from insects or spiders not normally considered poisonous.

Symptoms of a toxic reaction vary depending on the insect or spider, the toxicity of the venom, and the amount of venom injected. Most often, symptoms improve or go away within 48 hours. Although hives and difficulty breathing may occur in an allergic reaction, these symptoms will not occur in a toxic reaction. It is possible to have both a toxic reaction and an allergic reaction at the same time.

A toxic reaction may require immediate medical care or may lead to death. Signs and symptoms of a toxic reaction may include:

• Nausea or vomiting.
• Diarrhea.
• Fever.
• Weakness.
• Lightheadedness.
• Rapid swelling at the site of the bite or sting.
• Muscle spasms.
• Headache.
• Drowsiness.
• Fainting.

In addition to injecting venom, the sting or bite may also cause an infection that could require medical care. Symptoms of infection may include:

• Increased pain, swelling, warmth, or redness near the bite or sting.
• Red streaks leading from the bite or sting.
• Pus draining from the bite or sting.
• A fever.