What is the recommended treatment approach for a patient presenting with a spider bite, considering their individual medical history and potential for severe symptoms?

Spider Bite Treatment

For most spider bites, treatment consists of local wound care with thorough irrigation, ice application, over-the-counter pain medications, and watchful waiting—antibiotics are NOT indicated unless clear signs of secondary bacterial infection develop. 1, 2

Immediate Assessment

Quickly determine if this is a true emergency requiring immediate intervention:

• Call emergency services immediately if systemic symptoms develop: difficulty breathing, muscle rigidity, dizziness, confusion, or signs of anaphylaxis 3, 1
• Rapidly progressive swelling involving face, lips, tongue, or throat indicates angioedema requiring emergency intervention 2
• Remove rings and constricting objects immediately from the affected extremity before swelling worsens 1, 2

Initial Wound Care (First 24-48 Hours)

All spider bites should receive the following basic care:

• Thoroughly irrigate the wound with copious warm or room temperature water until no foreign matter remains 1, 2
• Apply ice with a clean barrier between ice and skin for local pain relief 1, 2
• Elevate the affected extremity to reduce swelling 2
• Apply antibiotic ointment and cover with a clean occlusive dressing to improve healing and reduce infection risk 1, 2

Pain Management

Use a stepwise approach for pain control:

• First-line: Over-the-counter acetaminophen or NSAIDs for pain control 3, 2
• Topical lidocaine 5% can be applied if skin is intact for additional pain relief 3, 2
• Oral antihistamines can reduce itching and associated discomfort 4, 2
• Cold compresses provide additional local pain and swelling reduction 4, 2

The Antibiotic Question: A Critical Pitfall

This is the most common error in spider bite management—do NOT prescribe antibiotics routinely:

• Large swelling in the first 24-48 hours is caused by allergic inflammation and mediator release, NOT infection 4, 2
• Universal prophylactic antibiotics are not recommended for bite wounds 3, 2
• Only prescribe antibiotics if clear signs of secondary bacterial infection develop: progressive erythema extending beyond the initial site, purulent discharge, or systemic signs like fever or elevated white blood cell count 3, 2

When secondary infection is confirmed or highly suspected:

• First-line oral therapy: Trimethoprim-sulfamethoxazole or doxycycline to cover MRSA, which is the predominant organism in infected spider bites (86.8% of cases in one series) 2, 5
• Alternative: Clindamycin if local resistance patterns permit 2

Large Local Reactions

For extensive swelling that persists beyond the immediate bite area:

• Consider a short course of oral corticosteroids for severe large local reactions, though definitive proof of efficacy through controlled studies is lacking 4, 3, 2
• Most large local reactions are IgE-mediated but self-limited 4

Brown Recluse Spider Bites (Loxosceles Species)

These require special consideration as they can cause progressive necrosis:

• Primary treatment remains rest, ice compresses, and observation 2, 6
• Surgical debridement should be delayed for several weeks to allow full demarcation of necrotic tissue 2, 6
• Monitor hemoglobin levels closely during the first week after suspected brown recluse bites, as systemic loxoscelism can cause massive hemolysis 6, 7
• For severe systemic loxoscelism with hemolysis: Consider therapeutic plasma exchange if patients do not respond to usual treatment and RBC transfusion 7
• Dapsone has been mentioned historically but is not emphasized in current guidelines 6

What NOT to Do

Avoid these common harmful interventions:

• Do NOT apply suction to the bite site—it is ineffective and potentially harmful 1, 2
• Do NOT apply tourniquets or pressure immobilization bandages—they may worsen tissue injury 1, 2
• Do NOT assume antibiotics are needed for swelling around the bite site 3, 1, 2
• Do NOT close infected wounds 2

When to Seek Medical Attention

Patients should return for evaluation if:

• Pain extends beyond the bite site or becomes severe 1, 2
• Pain is not controlled by over-the-counter medications 1, 2
• An open wound develops 1, 2
• Signs of infection appear (progressive erythema, purulent discharge, fever) 3, 1, 2
• Systemic symptoms develop 1, 2

Follow-Up Care

• Most patients with local symptoms only recover completely within 24-48 hours 1, 2
• Continue pain management with over-the-counter medications as needed for several days 1, 2
• Follow-up within 24 hours either by phone or office visit is advised 2
• Monitor for signs of secondary infection at the bite site 1, 2