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How to Identify Black Widow Spider Bites

Female black widow spiders can attack humans when they are provoked. The quick bite of the black widow spider has the power to paralyze large prey.

How To Identify The Bite

A spider bite can be distinguished from other insect bites by two faint red puncture spots at the site of the bite. However, with swelling and redness, the bite marks may not always be evident. Of course, confirming the bite is from a black widow spider is assured if the spider can be captured or seen when biting.

Venom & Toxicity

The black widow spider delivers the most toxic spider bite in the United States. The venom of the black widow spider is comprised of neurotoxins that affect the nervous system.

Bite Symptoms

The symptoms and gravity of black widow spider bites depends on where the bite occurs, the quantity of venom the spider injected and how sensitive the person who is bitten is to the spider’s venom. A black widow bite usually feels like a pinprick, though some individuals feel nothing at all.

Within the first hour of a bite, individuals may feel dull muscle pain throughout the entire body. The bite site later swells and turns red, forming a target-shaped lesion. Sensitive persons will likely report very intense pain and discomfort with the pain progressing from the site of the bite to finally localizing in the abdomen and back.

Severe symptoms usually start to improve within 2 to 3 days, but milder symptoms may persist for several weeks. Other symptoms may include nausea, perspiration, tremors, breathing difficulties, increased blood pressure and fever.

Usually, a black widow spider bite does not produce any tissue necrosis or sloughing of tissue. Long-term medical complications are extremely rare. However, always seek the advice and care of a physician when experiencing a black widow spider bite.

A victim's age and health condition are important factors in severity of symptoms. Small children and elderly patients are more at risk, as well as those with compromised immune systems and heart conditions.

Some individuals believe themselves to be having a heart attack while experiencing the effects of a black widow spider bite. Blood pressure and heart rate may also be elevated.

Harm inflicted by the black widow spider is unlikely fatal. Most people recover with medical treatment which can include antivenin injections.

Individuals who are bitten should seek medical attention immediately.

Why Do They Bite?

Like most other spiders, black widows bite to defend themselves when they feel threatened or whenever they are accidently stepped on or contacted by a person or pet.

Risks Associated With Infections

There is always a risk of secondary infection if the bite is not properly cleaned and disinfected.

How To Identify Bite On Pets

Veterinarians verify black widow bites by identifying bite marks and skin wounds or checking the abdominal muscles for rigidity. Very young and old dogs have weaker immune systems and are at increased risk of experiencing severe reactions to black widow bites. Pets should be taken to the vet immediately if bites are suspected.

Other symptoms in pets may include:

  • Whining or howling from pain

  • Trouble breathing

  • Inability to control muscles or stand

  • Vomiting and diarrhea

  • Death, if anti-venom treatment is needed and not given quickly


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