Most spider bites heal within a few days to a week. The redness, swelling, and itching from a typical non-venomous bite generally resolve on their own without treatment. Bites from venomous spiders like brown recluses or black widows follow a very different timeline, sometimes taking weeks or months to fully heal.
Non-Venomous Bites: A Few Days
The vast majority of spider bites come from harmless species. You’ll notice a raised, red, itchy bump at the bite site, similar to a mosquito bite. These symptoms typically last several days and clear up without any medical intervention. Swelling usually peaks within the first 24 to 48 hours and then gradually fades.
Applying ice, keeping the area clean, and leaving it alone is generally all you need. Over-the-counter antihistamines can help with itching if it’s bothersome, though no specific treatment has been shown to speed up the healing process for mild bites. If the bump lingers past a week or keeps growing rather than shrinking, that’s a sign something else may be going on.
Brown Recluse Bites: Weeks to Months
Brown recluse bites are painless at first. Over the next two to eight hours, the bite becomes increasingly painful. You might initially see two small puncture marks surrounded by redness. The center of the bite then turns pale while the outer ring stays red and swollen, a result of blood vessels constricting in the area.
Over the following days, a blister forms and the center shifts to a blue or violet color with a hard, sunken core. The tissue doesn’t begin to break down and ulcerate until 7 to 14 days after the bite. Around week six, the dead tissue (a dark, crusty layer called an eschar) typically starts to slough off on its own. After that, the wound heals gradually from the inside out.
Most brown recluse bites heal within three months, though some resolve faster in six to eight weeks. In more severe cases, skin grafting is needed to close the wound. One important detail: no commonly used treatment, including topical steroids, antihistamines, or oral steroids, has been shown to reduce healing time or lower the chance of scarring. A study published in the Journal of the American Board of Family Medicine found that none of these standard approaches made a measurable difference in how quickly bites healed. Systemic steroids may actually be harmful.
Black Widow Bites: Days of Systemic Symptoms
Black widow bites cause a different kind of problem. The bite itself may not look dramatic, but within minutes, severe pain radiates from the site along the blood vessels and can spread to the abdomen, chest, back, and limbs. The venom triggers a whole-body reaction rather than a localized wound.
Muscle cramps, abdominal stiffness, chest pain, difficulty breathing, and intense restlessness are common. In a study of 59 patients, nearly all developed systemic symptoms quickly after being bitten, and the average hospital stay was about six days. Most people recover fully with pain management and muscle relaxers. Antivenom, when used for more severe cases, is associated with faster symptom relief, lower hospital admission rates, and shorter stays. Some patients experience significant pain relief shortly after receiving it.
Black widow bites are rarely fatal, but young children and older adults face higher risks of serious complications.
When a Bite Isn’t Healing Normally
The biggest red flag is a wound that keeps getting larger instead of smaller. One case illustrates this well: a healthy 60-year-old applied antibiotic ointment at home for six days after a spider bite, only to notice on day seven that the wound was expanding and filling with fluid. Worsening after the first few days is not typical for a harmless bite.
Secondary bacterial infections are the most common complication. Bacteria can enter through broken skin at the bite site, causing the surrounding area to become hot, increasingly red, and painful. Streaks of redness spreading outward, pus, or fever all suggest infection rather than a normal bite reaction. In some situations, cultures for specific types of bacteria may be needed to guide treatment, especially if the wound continues to worsen despite initial care.
What Affects Your Healing Timeline
Several factors influence how quickly you recover. The species of spider matters most, but your own health plays a role too. People with weakened immune systems can experience delayed healing and more severe tissue damage from bites that might otherwise resolve uneventfully. Children are more vulnerable to serious outcomes from both brown recluse and black widow bites compared to healthy adults.
Location on the body also matters. Bites on areas with less blood flow, like the ears or the tip of the nose, tend to heal more slowly. Bites on fatty tissue, like the thighs or buttocks, are more prone to tissue damage from brown recluse venom because the toxin spreads more easily through fat. Keeping the bite clean, avoiding unnecessary poking or squeezing, and watching for signs of infection are the most practical things you can do to support a normal healing timeline, regardless of which spider bit you.