What is the treatment for arachnid (arthropod) bite?

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From the Guidelines

To treat a spider bite, prioritize wound care and pain management, and seek immediate medical attention if severe symptoms occur, as recommended by the 2024 American Heart Association and American Red Cross guidelines for first aid 1. When treating a spider bite, it is essential to follow a step-by-step approach to minimize morbidity, mortality, and improve quality of life.

  • First, clean the area with soap and water to prevent infection.
  • Apply an ice pack wrapped in cloth for 10 minutes at a time to reduce swelling and pain, as suggested by the guidelines 1.
  • Take over-the-counter pain relievers like acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) according to package directions to alleviate local pain.
  • Apply an antibiotic ointment like Neosporin to prevent infection and cover with a bandage.
  • Elevate the affected area if possible to reduce swelling. Most spider bites heal on their own within a week; however, it is crucial to monitor for systemic symptoms and seek immediate medical attention if severe pain, spreading redness, difficulty breathing, severe swelling, muscle cramps, or suspicion of a black widow or brown recluse spider bite occurs 1. The guidelines recommend calling emergency services if a person bitten by a spider or stung by a scorpion develops symptoms throughout the body, such as difficulty breathing, muscle rigidity, dizziness, or confusion 1. Additionally, medical care should be sought if pain extends beyond the site of the bite/sting, becomes severe, and is not controlled by over-the-counter pain medications; if an open wound develops; or if the person experiences symptoms throughout the body 1.

From the Research

Treatment Options for Spider Bites

  • The treatment for black widow spider bites typically involves managing symptoms, as the bites can cause severe pain, muscle cramping, abdominal pain, and back pain 2.
  • Antivenom (Antivenin Latrodectus mactans) is available and effective in treating black widow spider envenomation, but its use is often limited due to concerns about acute hypersensitivity reactions 2, 3.
  • Opioid analgesics combined with muscle relaxants, such as benzodiazepines, can provide temporary and symptomatic relief, but antivenom is considered the most efficacious therapy available 3.
  • A new purified F(ab)2 fragment Latrodectus mactans antivenom, Analatro®, is currently undergoing clinical trials and may offer similar efficacy with fewer adverse reactions compared to the currently available partially purified whole IgG Merck product 3.

Clinical Manifestations and Differential Diagnosis

  • Black widow spider bites can cause a range of symptoms, including muscle pain, diaphoresis, tachycardia, flushing, and hypertension 4.
  • The widow venom, a powerful neurotoxin known as a-latrotoxin, is responsible for these symptoms 4.
  • A high index of clinical suspicion coupled with a knowledgeable patient history is often necessary for successful treatment, especially when the treating physician is aware of the typical course and possible complications of black widow spider bites 4.

Symptom Management

  • Symptomatic treatment with a combination of opioid analgesics and muscle relaxants is commonly used to manage black widow spider bite symptoms 4.
  • Antivenom may be considered if symptom resolution fails, and an equine IgG antiserum is available for treatment 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Black widow spider (Latrodectus mactans) antivenom in clinical practice.

Current pharmaceutical biotechnology, 2012

Research

The black widow spider bite: differential diagnosis, clinical manifestations, and treatment options.

The Journal of the Louisiana State Medical Society : official organ of the Louisiana State Medical Society, 2015

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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