Some side effects of bug bites include itching, bruises, hives, and lesions or sores, states Healthline. Sometimes an individual can experience a severe allergic reaction called anaphylaxis when the throat swells shut and inhibits breathing. If the insect is a carrier of malaria, yellow fever, meningitis and West Nile virus, the side effects can be more severe and include fatigue, fever, vomiting, muscle weakness and confusion.
Side effects of bug bites vary according to the type of bug and whether or not the individual has an allergy to the insect's venom, explains LiveScience. Ticks can cause swelling and pain at the bite area, blisters, rash and difficulty breathing as well as more severe symptoms if the tick is a carrier of Rocky Mountain spotted fever or Lyme disease.
Side effects of spider bites vary according to the type of spider, according to LiveScience. While many spider bites cause only mild effects, such as redness, rashes and itching, the bite from a brown recluse spider causes lesions and ulcers in the skin that blister and blacken before killing the tissue if untreated. It can also cause fever and nausea. The bite from a black widow can result in paralysis, cramping, nausea and vomiting.