From the Guidelines
If you suspect an infected spider bite, clean the area with soap and water, then apply an antibiotic ointment like Neosporin or Polysporin and cover with a clean bandage. Take over-the-counter pain relievers such as ibuprofen (Advil, Motrin) at 400-600mg every 6 hours or acetaminophen (Tylenol) at 500-1000mg every 6 hours as needed for pain, as recommended by the 2024 American Heart Association and American Red Cross guidelines for first aid 1. Watch for signs of worsening infection including increasing redness, warmth, swelling, pus, red streaks extending from the bite, fever, or severe pain. These symptoms require immediate medical attention, as you may need prescription oral antibiotics like cephalexin 500mg four times daily for 7-10 days. Most spider bites become infected due to bacteria on the skin entering the wound, not from the spider's venom itself, and irrigation of the wound and debridement of necrotic tissue are crucial in preventing infection 1. Black widow and brown recluse spider bites can cause serious systemic symptoms and require immediate medical care regardless of infection status, with emergency services recommended if symptoms such as difficulty breathing, muscle rigidity, dizziness, or confusion develop 1. Keep the bite elevated when possible and apply cold compresses for 20 minutes several times daily to reduce swelling and discomfort while the infection heals. It is essential to seek medical care if pain extends beyond the site of the bite, becomes severe, and is not controlled by over-the-counter pain medications, or if an open wound develops 1.
From the Research
Infected Spider Bite
- Most spider bites cause minimal or no effects, with local irritation being the most common symptom 2
- However, some spider bites can lead to significant morbidity and rarely, mortality 2, 3
- Secondary infection can occur as a result of a spider bite, although this is not always the case 3
- In Australia, skin ulceration is more likely to be caused by an infective, inflammatory, or traumatic cause rather than necrotising arachnidism 2
- The diagnosis of a spider bite can be challenging, as the spider is often not seen at the time of the suspected bite, and lay identification of the spider is not reliable 2, 3
- Clinicians should consider spider bite in the differential diagnosis of unexplained autonomic and neurological dysfunction, particularly in children 2