Detecting Dangerous Symptoms From Poisonous Spider Bites

May 7th 2016

Although most spiders are so small that they cannot even penetrate human skin with their bites, there are a few highly dangerous species. If you notice spreading or severe symptoms following a bite by a spider or an unknown bug, contact a doctor immediately.

Worsening Symptoms

Harmless bites may have few symptoms initially, but spread into a larger bump and maybe even a small rash within 24 hours. They may be painful or itchy. This is generally nothing to worry about. However, if the symptoms continue to progress for more than 24 hours following the bite, it is time to see a doctor.

If your symptoms are severe, you may want to consider calling a doctor earlier. Severe pain or rapidly progressing symptoms may be signs of a more severe bite.

Full-Body Symptoms

Harmless spider bites can be painful, but the pain should be fairly localized to the site of the actual wound. However, more venomous spiders may inject toxins that cause problems in other parts of the body. These symptoms may be similar to those of a fever, including sweating, chills, body aches and headaches. Muscle cramps, particularly in the arms and legs, and stomach cramps or other digestive problems can also occur. Some people may experience feelings of fatigue. In more severe cases, an elevated heartbeat can be felt.

These symptoms are particularly associated with black widow bites, which contain a neurotoxin which can be very dangerous for people. If you experience these, particularly if you notice a small bite with two puncture wounds, seek immediate medical attention.

Signs of Allergic Reaction

Some people are allergic to spider venom, just like others are allergic to bee stings. Although this problem does not affect everyone, it can occur even when the species that bites you is fairly harmless. If you notice a spreading rash, hives, or feel unusually warm and flushed, consider seeking medical attention. More severe symptoms include swelling of the mouth or throat, difficulty breathing, dizziness and nausea. These can be signs that you are experiencing anaphylaxis, which is a potentially life-threatening emergency.


Spider bites are a fairly common occurrence, and most are harmless. They may cause a little pain or irritation, but no more than any other bug bite. However, some species do have venom that can cause severe complications for human beings. In the United States, the two most significant dangerous species are the brown recluse and the black widow. Since most people do not even notice the initial bite, it can be hard to tell when to seek medical attention. If you notice any of the following symptoms after a spider bite, seek medical help immediately.

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