Most spider bites can be treated at home with basic first aid: clean the wound, apply a cool compress, and take an over-the-counter pain reliever. The vast majority of spider bites cause only mild, localized reactions that resolve on their own within a few days. Bites from black widows or brown recluses, however, can cause serious symptoms that need medical attention.
Immediate First Aid for Any Spider Bite
Whether or not you can identify the spider, the initial steps are the same. Wash the bite area with mild soap and water, then apply antibiotic ointment to help prevent infection. Place a cool, damp cloth or a cloth-wrapped ice pack over the bite for about 15 minutes each hour to bring down swelling and ease pain. If the bite is on an arm or leg, keep that limb elevated when you can.
For pain, a standard over-the-counter pain reliever works well. If the area is itchy or slightly swollen, an antihistamine like diphenhydramine (Benadryl) or cetirizine (Zyrtec) can help. Most bites from common house spiders need nothing more than this.
When a Bite Needs Emergency Care
A small number of spider species, most notably black widows and brown recluses, can cause reactions that go beyond localized pain and redness. Get medical help right away if you notice any of the following:
- Difficulty breathing
- Heart palpitations or a racing pulse
- Nausea and vomiting
- Severe muscle pain, cramping, or weakness
- Severe headache or vision problems
- Signs of infection such as fever or yellow discharge from the bite
Children under 16 and adults over 60 are at higher risk for serious complications and may need hospitalization for breathing problems, heart issues, high blood pressure, or intense muscle cramping.
Black Widow Bite Treatment
Black widow venom is a neurotoxin, meaning it affects the nervous system rather than destroying tissue at the bite site. The hallmark symptom is severe, spreading muscle pain and rigidity, often starting near the bite and radiating outward. Treatment focuses on controlling that pain and muscle spasm.
For otherwise healthy adults between 16 and 60, doctors often manage symptoms with muscle relaxants and pain medication rather than jumping straight to antivenom. Warm baths and intravenous calcium can also help relieve muscle cramping. Stronger pain medications may be needed in some cases, though doctors use them carefully because the venom itself can affect breathing.
Antivenom exists specifically for black widow bites and provides the fastest relief. It’s generally reserved for more severe cases and is considered preferred initial therapy for patients over 60, who face a higher risk of complications. Younger, healthy patients typically recover with supportive care alone, though the pain can be intense for 12 to 24 hours.
Brown Recluse Bite Treatment
Brown recluse bites are a different challenge. The venom contains an enzyme that can destroy skin tissue, sometimes creating a necrotic wound, an area of dead skin that darkens and eventually ulcerates. Not every brown recluse bite leads to this; many heal without significant tissue damage.
The key enzyme in the venom is temperature-sensitive, which is why cooling the bite during the first 72 hours is especially important for brown recluse bites. Cool compresses should be applied consistently until the wound stops progressing. Beyond cooling, treatment involves keeping the affected area elevated, loosely immobilized, and clean.
The majority of brown recluse bites heal within about three weeks. In severe cases where the skin breaks down into a deep ulcer, healing can take several months. These more serious wounds may eventually need evaluation by a plastic surgeon or wound care specialist for possible skin grafting. Various treatments like steroids, specialized medications, and early surgical removal of the wound have been tried over the years, but none has strong enough evidence to be considered standard practice. The most reliable approach remains good wound care and patience.
Watching for Infection
Secondary bacterial infection is the most common complication of any spider bite, including bites from harmless species. The bite creates a small break in the skin, and scratching or inadequate cleaning can introduce bacteria. Watch for increasing redness that spreads outward from the bite, warmth around the area, swelling that gets worse rather than better, fever, or any pus or yellow discharge. If these signs appear, you likely need a course of antibiotics. Keeping the wound clean with soap and water, applying antibiotic ointment, and resisting the urge to scratch are the best ways to prevent this.
Tetanus Considerations
Spider bites that cause tissue breakdown or necrotic wounds fall into what the CDC considers “dirty or major wounds,” the same category as animal bites and crush injuries. If you’ve completed your tetanus vaccine series and your last shot was more than five years ago, a booster is recommended for these higher-risk wounds. For a clean, minor bite with no tissue damage, you generally don’t need a booster unless it’s been more than 10 years. If you’re unsure of your vaccination history or never completed the full series, a tetanus shot is recommended regardless of wound type.
What Recovery Looks Like
A typical spider bite from a common species follows a predictable pattern: redness and mild swelling for a day or two, some itching as it heals, and full resolution within a week. Black widow bites cause more systemic misery, with muscle pain and cramping that can last one to three days even with treatment, but they rarely leave lasting damage at the bite site itself. Brown recluse bites are the slowest to heal. A bite that develops a necrotic center will go through stages: the area darkens over the first week, dead tissue eventually sloughs off leaving an open ulcer, and new skin gradually fills in. Simple cases wrap up in three weeks; severe ones can stretch to several months and may leave a scar.
Throughout recovery from any spider bite, keep the area clean, continue applying cool compresses as needed for comfort, and monitor for signs of infection. If a bite that seemed minor starts getting worse after the first 24 to 48 hours rather than better, that’s worth a call to your doctor.