Spider Bite Treatment: First Aid and When to See a Doctor

Knowing how to treat a spider bite properly can prevent complications and speed healing. While the vast majority of spider bites are harmless and resolve on their own, bites from venomous species like black widows and brown recluses require prompt medical attention.

First Aid for Any Spider Bite

Follow these steps immediately after being bitten by any spider:

Step 1: Clean the Wound

Wash the bite area thoroughly with soap and warm water. This reduces the risk of secondary bacterial infection, which is actually the most common complication of any spider bite.

Step 2: Apply Cold

Wrap ice or a cold pack in a cloth and apply to the bite for 10 to 15 minutes at a time, with breaks in between. Cold reduces swelling, numbs the area, and slows the spread of venom.

Step 3: Elevate

If the bite is on an arm or leg, elevate the limb above heart level to reduce swelling.

Step 4: Manage Pain and Itching

• Over-the-counter pain relievers such as ibuprofen or acetaminophen help with pain.
• Antihistamine cream or oral antihistamines (diphenhydramine) reduce itching and minor swelling.
• Hydrocortisone cream can help with localized itching and inflammation.

Step 5: Monitor

Watch the bite site over the next 24 to 48 hours for signs of worsening:

• Increasing redness or swelling
• Development of a blister or dark center
• Red streaking from the bite (sign of infection)
• Fever, chills, or muscle pain

Treatment by Spider Type

Treating a Black Widow Bite

Black widow bites cause neurotoxic symptoms that can be severe:

• Apply first aid as described above.
• Go to the emergency room immediately — do not wait for symptoms to develop.
• Muscle cramps, abdominal pain, and sweating require professional management.
• Doctors may administer pain medication, muscle relaxants, or antivenom.

Treating a Brown Recluse Bite

Brown recluse bites may cause tissue necrosis:

• Apply first aid as described above.
• Seek medical attention within 24 hours of the bite.
• Do not apply heat or attempt to drain any blister.
• A doctor will assess the wound and determine if further treatment is needed.
• Necrotic bites require ongoing wound care.

Treating Non-Venomous Spider Bites

Bites from wolf spiders, jumping spiders, house spiders, and other common species:

• First aid described above is typically all that is needed.
• Symptoms usually resolve within a few hours to a few days.
• See a doctor if signs of secondary infection develop.

What NOT to Do

• Do not apply a tourniquet.
• Do not cut the bite or try to suck out venom.
• Do not apply heat, which can worsen tissue damage.
• Do not apply topical antibiotics unless a doctor recommends them.
• Do not ignore worsening symptoms.

When to Call 911

Call emergency services if the person bitten experiences:

• Difficulty breathing or shortness of breath
• Severe chest pain or tightness
• Swelling of the face, lips, or throat
• Severe muscle spasms
• Loss of consciousness
• Signs of anaphylaxis

Preventing Spider Bites

Prevention is always better than treatment:

• Shake out shoes and clothing before wearing, especially items stored in garages or basements.
• Wear gloves when handling firewood, stored items, or working in sheltered areas.
• Keep beds away from walls and bedding off the floor to prevent spiders in bed.
• Follow spider prevention tips to reduce indoor spider populations.
• Learn to identify venomous spiders in your region.

For more on spider bites and spider safety, see our complete guide to spiders.

Expert Insights

In 15 years of pest management, I have been on-site for numerous spider bite incidents and have always stressed the importance of proper identification. I once responded to a frantic call from a mother whose child had been bitten by a spider in their garage. I identified the spider as a common sac spider — not medically significant — which allowed the family and their doctor to provide appropriate care without unnecessary emergency measures. Keeping the spider for identification made all the difference. — Sarah Mitchell, BCE

Sources and References

• Centers for Disease Control and Prevention (CDC)
• National Pest Management Association (NPMA)
• University of California Riverside Spider Research
• Ohio State University Extension

Main Causes

Spider bites requiring treatment occur when a spider is defensively compressed against skin. The scenarios that produce bites in the real world are consistent across species: reaching bare-handed into woodpiles, storage boxes, or garden areas where spiders shelter; putting on shoes, boots, or gloves stored in garages or sheds without shaking first; pulling on clothing left on the floor in recluse-endemic areas; and rolling onto a spider in bedding that is touching the floor or wall. Spiders do not hunt humans and have no predatory interest in biting. Defensive bites, particularly from black widows and brown recluses, are the primary scenarios requiring medical intervention. The CDC emphasizes that most wounds attributed to spider bites, particularly necrotic lesions outside the recluse's geographic range, are actually bacterial infections and require physician evaluation regardless of assumed cause.

How to Identify

Distinguishing a spider bite from other skin conditions affects treatment decisions. A spider bite is a single-event wound - one site, at one point in time, with no additional sites appearing over subsequent nights. The bite may produce two small puncture marks close together, though these are often not visible. Redness, swelling, and local pain develop within one to three hours for most species. Black widow bites produce progressive systemic symptoms - muscle cramping, abdominal pain, sweating - beyond the bite site. Brown recluse bites may develop a characteristic bull's-eye appearance after several hours, with a pale center, darker ring, and outer redness. Multiple lesions appearing over several nights are almost never spider bites - investigate for bed bugs, fleas, or other biting arthropods. Any expanding, darkening wound warrants physician evaluation.

Prevention

Preventing bites is more effective than treating them. Shake out all footwear stored in garages, closets, or basements before wearing - this habit alone eliminates the most common bite scenario. Wear leather or heavy fabric gloves for any work involving stored items, firewood, or outdoor debris. Store clothing in sealed containers or zip-lock bags if you live in brown recluse or black widow territory. Keep bedding off the floor and pull beds away from walls. Seal foundation cracks and install door sweeps to reduce the indoor spider population that creates contact opportunities. Place sticky traps in garages and basements to monitor for medically significant species and intercept them before contact occurs. These behavioral and structural measures, recommended by UC IPM and Penn State Extension, reduce bite risk more reliably than any treatment approach.

Risk and Severity

Most spiders found in and around North American homes pose no medical risk to humans and provide net benefit by reducing other pest populations. Two species warrant medical caution: the black widow, whose venom can produce systemic symptoms including muscle cramping, abdominal pain, and elevated blood pressure; and the brown recluse, whose bite can produce a slowly developing necrotic lesion in a minority of cases. Bites from either species generally respond well to medical care, and fatalities are extremely rare. The far more common spider-related problem is aesthetic — webs, egg sacs, and visible spiders cause distress without medical significance. Risk concentrates in undisturbed storage areas, garages, basements, and outbuildings.

Solutions and Actions

For most spider species the goal is removing webs and reducing prey rather than chemical treatment. Vacuum or sweep down all visible webs weekly, including egg sacs, in garages, basements, attics, eaves, and exterior corners. Reduce indoor insect populations by maintaining screens, sealing entry points, and addressing any active pest issue — fewer insects means fewer spiders. Apply a residual insecticide barrier to the foundation perimeter, around windows and doors, and in eaves to deter newly arriving spiders. For confirmed black widow or brown recluse populations in storage areas, use professional pest control, wear long sleeves and gloves when handling stored items, and shake out shoes and clothing left in garages or basements. Single sightings indoors without webs are usually transient and need no chemical response.

Frequently Asked Questions

What should I do immediately after a spider bite?

Clean the bite area with soap and water, apply a cold compress to reduce swelling, and elevate the affected area if possible. Take over-the-counter pain relievers if needed. If you can safely capture the spider, do so for identification. Seek medical attention if symptoms worsen or if you suspect a black widow or brown recluse bite.

When should I go to the doctor for a spider bite?

Seek medical attention if you experience severe pain, muscle cramps, abdominal pain, difficulty breathing, a growing area of redness, signs of infection (increasing warmth, pus, red streaks), or if the bite does not improve within a few days. Always seek immediate care for suspected black widow or brown recluse bites.

How do I know if a spider bite is infected?

Signs of infection include increasing redness that spreads beyond the bite area, warmth and swelling, pus or drainage, red streaks extending from the bite, fever, and worsening pain after the first day. If you notice any of these signs, seek medical attention promptly, as infections can become serious if left untreated.

Do I need antibiotics for a spider bite?

Most spider bites do not require antibiotics. However, if the bite becomes infected — which can happen with any wound — antibiotics may be necessary. A healthcare provider can assess whether infection is present and prescribe appropriate treatment. Do not take antibiotics without medical guidance.