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EspañolSpider bite symptoms: What are the early signs of spider bite?
Overview: What do spider bites feel like?
Spider bites are common but rarely a cause for concern. Most spiders can’t puncture human skin with their fangs, and their venom isn’t powerful enough to create problems. However, two types of spiders in the U.S.—widows and brown recluse spiders—can make people seriously ill after a bite.
Brown recluse ( “violin” or “fiddle back”) spider venom breaks apart human cells. The bite is typically painless for a few hours, but once it starts hurting, the pain gets worse. The site will look red and swollen but could eventually blister and develop into a large or ugly sore in a few days. If the venom spreads to the rest of the body, other symptoms might include nausea, muscle pain, headache, and feeling very sick. In children, the reaction may be more severe.
Black widows are the most recognizable widow spiders, but all widow venom affects the nerves. The bite may not be noticed at first, or the pain may start immediately and spread very fast. There may be muscle spasms or sweating near the bite. For most people, these initial symptoms typically resolve in a few days. If the venom spreads, the pain can gradually migrate to the rest of the body. Muscle spasms, sweating, nausea, and vomiting are common symptoms of widow venom poisoning.
While brown recluse spiders and widows are responsible for potentially dangerous spider bites, some types of tarantulas and hobo spiders have venom that could produce painful bites and sometimes other symptoms, but never anything life-threatening.
Key takeaways:
Spider bite is a common health condition that can affect anyone regardless of age, sex, race, or ethnicity.
Early signs of a spider bite include irritation, pain, redness, and swelling.
Any bite from a widow spider or brown recluse spider should receive immediate medical attention and first aid. Serious symptoms of a spider bite, such as severe pain at the bite location, muscle spasms, muscle pain, abdominal pain, difficulty breathing, symptoms of low blood count, or the formation of a large wound at the original site, may require immediate medical attention.
You may be at risk for spider bites if you live in an area with venomous spiders.
Spider bite requires a medical diagnosis.
A spider bite generally does not require treatment, but venomous spider bites should be seen by a healthcare professional. Spider bite symptoms typically resolve within hours or days. Even venomous spider bites typically resolve without treatment in a few days or weeks, but severe venomous spider bites will require treatment. Symptoms typically resolve in a few days with treatment.
Treatment of spider bites may include first aid, over-the-counter painkillers, antihistamines, opioids, benzodiazepines, antibiotics, antivenom (for black widow spider bites), tetanus vaccine, skin grafts (brown recluse spider bites), or hospitalization in severe cases.
Untreated spider bites could result in complications like hemolytic anemia, organ failure (in children), and death (very rare).
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What are the early signs of spider bite?
The earliest signs of spider bite happen around the bite:
Puncture marks
Mild pain or stinging (many spider bites will be painless or only mildly painful)
Irritation
Swelling
Redness
The earliest symptoms following a widow bite may also include:
Immediate pinprick sensation when bitten
Dull pain or numbness immediately after the bite
Mild to more severe pain over time
In a few hours, the pain may spread
Sweating around the bite area
Muscle cramps near the bite area
Fast heartbeat
Fast breathing
High blood pressure
Brown recluse bites are often painless initially but become painful over the next few hours. The bite area might look like a bullseye, pale or blue in the center, surrounded by red skin.
Other spider bite symptoms
Many widow and brown recluse bites do not involve much more than the bite area. If the venom travels to other places in the body, systemic symptoms will start appearing.
Brown recluse bites can produce severe symptoms around the bite area. Tissue death from brown recluse venom appears as a large, dark sore around the bite.
Brown recluse venom may spread to the rest of the body over several days or a few weeks. When this happens, systemic symptoms include:
Nausea
Headache
Feeling sick
Muscle pain
Severe and life-threatening symptoms are uncommon but are more likely in young children. The most severe symptoms of a recluse bite include:
Fever
Weakness
Joint pain
Internal bleeding or clots
Low blood counts
Seizures
Organ failure
When widow venom spreads to the rest of the body, symptoms include:
Pain that spreads to the rest of the body
Abdominal or back pain
Muscle pain
Muscle spasms
Sweating
Salivating
Overactive reflexes
System-wide symptoms of a widow bite can happen within the first few hours of the bite and usually last for 12 to 48 hours after the bite.
Spider bite vs. mosquito bite symptoms
Though irritating, mosquito bites are usually more itchy than painful. Although some people may react to a mosquito bite with redness, swelling, hives, or a fever, most people will experience a red bump with itching. But there may be significant differences between mosquito bites and venomous spider bites like those of brown recluse and widow spiders:
| Venomous spider bite | Mosquito bite | |
| Shared symptoms |
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| Unique symptoms |
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RELATED: How to treat the bites and stings of summer
Types of spider bites: How can I tell which one I have?
Although all spiders can bite, in the U.S., only brown recluse and widow spiders can make people truly sick. There are three ways to tell the difference between a recluse bite and a widow bite. The first is to identify the spider itself. The second is to figure out where the spider bite happened. If it happened in bed, it’s probably a recluse. If it happened when cleaning out the garage, it’s probably a widow. Symptoms are the third way to identify a spider bite. Here’s a comparison:
| Widow spiders | Recluse spiders |
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| Initial symptoms | |
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| Systemic symptoms | |
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When to see a doctor for spider bite symptoms
If you know or think you’ve been bitten by a venomous spider, either a widow or recluse, get immediate medical attention. If the spider is dead, bring it along to be identified.
Spider bites are difficult to diagnose. It helps if the spider is brought with the patient so that it can be identified. That isn’t always possible. Recluse symptoms often don’t appear until hours after the bite and the person with the bite may never have seen the animal that bit them.
Without a spider to identify, healthcare professionals make a diagnosis based on the description and circumstances of the bite, symptoms, and the appearance of the bite area. Systemic symptoms of a widow bite may be evident since they start fairly quickly after the bite, but systemic symptoms of a recluse bite can take weeks to develop. In those cases, the healthcare provider will warn people to watch for these symptoms and return for medical help if they appear.
Complications of spider bite
The most severe complications of venomous spider bites are:
Infection
Areas of skin death
Hemolytic anemia (recluse spiders)
Decrease in blood-clotting cells (in young children bitten by a recluse)
Organ failure (in young children bitten by a recluse)
While most people think of widows and recluse spiders as deadly, their bites only very rarely kill people. In a large-scale study, 65% of people bitten by a widow spider had only mild problems that quickly resolved. 34% had moderate and longer-lasting problems, and 1.4% had severe effects from the bite. There were no deaths. Recluse spider venom is more dangerous, but life-threatening problems primarily affect young children. Death due to a recluse bite is extremely rare.
How to treat spider bite symptoms
Venomous spider bites should be examined by a healthcare provider as soon as possible. Treatment consists of immediate first aid, symptomatic treatment, and, if the venom spreads, treatment of systemic problems.
First aid consists of cleaning the wound with soap and water, applying ice packs to the wound, and elevating the affected area. For most bites, including harmless ones, a doctor may give a tetanus shot if vaccinations are not up-to-date. Pain is usually treated with over-the-counter pain relievers. Swelling can be handled with oral or topical antihistamines. Healthcare professionals may prescribe opioids if the pain is severe or spreads throughout the body. Severe muscle spasms and rigidity are treated with benzodiazepines.
Severe problems will require more involved treatment. Dead skin tissue due to recluse poisons will need to be removed. Topical or oral antibiotics may be used to prevent skin infection at the wound. Severe systemic problems may require hospitalization. In the most severe cases of widow bite, antivenom may be used. Finally, if a recluse bite destroys enough skin tissue, skin grafts may be needed.
Signs that a spider bite is getting better
In nearly all cases, venomous spider bites get better, and the symptoms improve. For widow bites, the pain and swelling usually go away within days. Once this has happened, there’s no danger of future symptoms from the bite. Systemic symptoms of a widow bite often improve within days but may last longer. Again, when these symptoms pass, the crisis is over.
A recluse bite also gets better over time, again primarily marked by a lessening of the pain. However, if the initial bite improves, be on the lookout for systemic symptoms for the next few days or weeks. If three weeks go by without systemic symptoms after a recluse bite, then the crisis is probably over.
Most importantly, get medical treatment
If you’re worried about a venomous spider bite, then see a healthcare professional. It may be nothing, but it’s worth finding out. Sometimes, people won’t know they’ve been bitten. If there are troubling symptoms like intense pain at the bite site, pain spreading to the rest of the body, a growing ulcer on the skin, fever, or other serious symptoms, get immediate medical care.
FAQs about spider bite symptoms
What are the symptoms of a brown recluse spider bite?
Recluse venom works slowly, so the first symptoms may take hours to appear. The first sign is usually pain at the bite site that steadily worsens. The area will become red and swollen and eventually turn into a sore, a blister, and even a dark, dead patch of skin.
What are the symptoms that a spider bite is getting worse?
A venomous spider bite is something to worry about when symptoms spread to other parts of the body. These include pain, muscle cramps, muscle pain, nausea, vomiting, fever, headache, and other symptoms that have no relation to the place that was bitten. These symptoms mean that the poisons have spread to the body, so medical attention is needed.
Does Neosporin help with spider bite symptoms?
Neosporin and other topical antibiotics do not help problems due to spider venom. However, they are good at preventing bacterial infections at the site. Applying over-the-counter antibiotics to a bite area is a common first-aid response to insect bites, spider bites, and stings.
What’s next? Additional resources for people with spider bite symptoms
Test and diagnostics
Brown recluse spider bites, Cleveland Clinic
Common spider bites, American Family Physician
Insect bites, StatPearls
Treatments
Arthropod bites and stings, American Family Physician
Black widow spider toxicity, StatPearls
Brown recluse spider toxicity, StatPearls
Symptoms of venomous spider bites and first aid, Centers for Disease Control and Prevention (CDC)
Scientific studies and clinical trials
A U.S. perspective of symptomatic Latrodectus spp. envenomation and treatment: a National Poison Data System review, Annals of Pharmacology
Envenomation by an arachnid (Latrodectes or Steatoda): case report involving a woman and her female dog, Case Reports
More information on related health conditions
How to treat the bites and stings of summer, SingleCare