Spider bites

21:55 - 4 May , 2021


What is Spider bites?

Spider bites are actually 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 other times damage that they did not cause is attributed to spiders. 

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

There are only certain poisonous spiders whose venom is so powerful as to cause severe symptoms and even endanger life. 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. 


Most spider bites do not usually cause symptoms or if they do, it is 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.

If you have the following symptoms, go to your doctor or to the ABC Emergency Room:

  • You have intense pain throughout your body, especially in the abdominal area.
  • The ulcerative lesion caused by the bite begins to spread, increasing its size.
  • You have 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

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.
  • In the wide part of the body, an hourglass shape with an intense red hue can be seen. 

Violin Spider characteristics:

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

Common treatment for these cases includes: 

  • Hygiene and disinfection of the wound.
  • Application of topical antibiotic. 
  • 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 being high risk due to possible allergic reactions, it is used at the doctor’s discretion.

At the Neurological Center, a select group of highly professional and certified doctors in the various neurological specialties are 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 the prevention, diagnosis, treatment, and rehabilitation of nervous system diseases, always focusing our activities on your safety.

Nervous system specialties

  • Neurology
  • 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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The dissemination of the content of this material is for informational purposes only and does not replace, under any circumstance or condition, a consultation with a specialist doctor, for which the ABC Medical Center is not responsible for the different use that may be given to it. If you require more information related to the subject, we suggest you contact the specialist doctor you trust directly.