ABC Medical Center > Spider bites

What is Spider bites?

21:55 - 4 May , 2021


Spider bites are in fact bites since these insects have jaws and fangs. The injuries they cause are often confused with those of other insects or with skin infections, while sometimes other insects’ bites or skin lesions are attributed to spiders.

Most spider bites are completely harmless and cause almost no symptoms, although some can cause inflammation, discomfort, and itching.

There are only certain poisonous spiders whose venom is so powerful as to cause severe symptoms and can even be life-threatening. The two most toxic spiders are:

  • Black widow.
  • Brown recluse or violin spider.

Both spiders only attack when they feel attacked, they usually live in places of the house that are not frequently visited, where they feel calm and where there is practically no movement, such as bookcases, closets, sheds, and messy or seldom-used rooms.

Signs and symptoms Spider bites

Most spider bites do not usually cause symptoms or if they do, they are mild, but in the case of the two aforementioned spiders, the most frequent symptoms are:

Black widow:

  • Swelling and intense pain in the injured area, radiating to the abdomen, chest, and back.
  • Acute abdominal pain that is often confused with appendicitis.
  • Nausea, vomiting, sweating, and chills.

Violin spider:

Symptoms typically worsen after seven hours from the bite:

  • Intense pain in the affected area and throughout the body.
  • High fever and chills.
  • Necrosis in the tissues around the bite that slows healing.

You should see your doctor or to the ABC Emergency Room if you have the following symptoms:

  • Intense pain throughout your body, especially in the abdominal area.
  • The lesion caused by the bite begins to spread, increasing its size.
  • Breathing difficulties.

In certain cases, where the bitten person is more susceptible to the spiders’ poison, the symptoms are magnified and can become fatal, especially in children.

Diagnosis and treatment Spider bites

If you are not sure that a spider bit you, the doctor, when analyzing your symptoms and observing the injury, may infer that it is a spider bite, but if you saw the insect in question, you should describe it to identify the specimen.

Morphological characteristics of the black widow:

  • Glossy black body no larger than two or three centimeters with rows of elongated legs.
  • An hourglass shape with an intense red hue can be seen in the wide part of the body.

Violin spider characteristics:

  • 20 millimeters long, brown or beige body, with elongated legs, and a violin shape.
  • Six eyes instead of the eight that spiders usually have.

A common treatment for these cases includes:

  • Cleaning and disinfecting the wound.
  • Application of topical antibiotics.
  • Oral analgesics and antihistamines.
  • Use of ice to reduce inflammation and pain.
  • Tetanus vaccine.

When the symptoms are severe and can be fatal, the intravenous application of an antidote for black widow bites is required, but it is used at the doctor’s discretion as it is high risk due to possible allergic reactions.

At the Neurology Center, a select group of highly trained and certified doctors in various neurological specialties is ready to assist you with the quality and warmth that characterizes us.

Our mission is to provide you with comprehensive and multidisciplinary care programs for preventing, diagnosing, treating, and rehabilitating nervous system diseases, always focusing on your safety.


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  • Neurosurgery
  • Spine surgery
  • Pediatric neurosurgery
  • Neurophysiology
  • Neuro-rehabilitation
  • Neuro-pathology
  • Interventional neuro-radiology
  • Neuropsychology
  • Neuro-oncology
  • Neuro-otology
  • Epilepsy
  • Neuro-ophthalmology
  • Neuroimaging


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