Ticks. Tick bites are not life-threatening but may cause diseases such as Rocky Mountain spotted fever, Lyme disease, tularemia, relapsing fever, and a potentially fatal ailment called ehrlichiosis.
Spiders. Bites are seldom fatal; infants, the elderly, and people with allergies are at greatest risk. Most dangerous is the black widow spider.
Scorpions. Scorpion stings cause a sharp, burning pain, followed by numbness. Scorpion venom rarely produces shock, or even a life-threatening syndrome of rapid breathing, difficulty speaking, and muscle spasm.
Fire ants. These ants produce small, fluid-filled bites that may form an ulcer. The ants bite into the skin and then sting repeatedly in an arc around the bite. The venom is capable of causing severe reactions and even, in some cases, anaphylaxis and death.
Most insect bites produce only minor irritation, with symptoms such as:
- Swelling at the site of the bite
- Local numbness
Bites of poisonous spiders and scorpions may produce these symptoms:
- Intense pain at the site of the wound
- Stiffness or joint pain
- Muscle spasms
- Abdominal pain, nausea or vomiting
- Fever or chills
- Difficulty breathing or swallowing
- A spreading, ulcerated wound or tissue death
- Dizziness, impaired speech or convulsions
An insect or spider bite can rarely cause a potentially fatal allergic reaction known as anaphylactic shock. Symptoms can include:
- Chest pain
- Face or mouth swelling
- Difficulty swallowing
- Difficulty breathing