Signs and Symptoms of Spider Bites
urbazon / Getty Images
Medically reviewed by William Truswell, MD
Spiders are normally not aggressive and do not attack humans or bite them at random. Most spiders only bite when they are cornered, trapped, or contacted by a person—such as when you reach into a dark corner or slide on a pair of boots. This can cause them to act in self-defense and bite you.
If you are bitten by a spider, symptoms may include pain, swelling, or itchiness. More serious symptoms can occur if a venomous spider (such as a black widow) bites you.
Common Symptoms
Very few spiders in the United States cause serious illness or even death. Most spider bites will often resemble a bee sting. Unless you saw the spider bite you, it is very hard to distinguish a spider bite from an insect sting. Spider bite symptoms include the following:
Redness
Rash
Tingling
Burning
Stinging
Pain at the site
A venomous spider bite might lead to more severe symptoms.
Brown Recluse Spider Bite Symptoms
The brown recluse spider is not aggressive, but it has a dangerous bite. People usually get bitten by this spider when they reach into a dark box in the basement or put on shoes or clothes where the spider is hiding.
The venom from the brown recluse spider is complex and highly poisonous. A bite may initially look like a typical insect bite. It is not until the venom spreads that severe symptoms begin to develop, especially as it starts to destroy surrounding tissues.
In addition to a significant wound, people can develop a fever, chills, and nausea. As time passes, their wound will become larger and darker in color due to necrosis (tissue death). It may develop an ulcer and turn black. The venom might also spread to fat and muscles and become infected.
This infection can even spread to the rest of your body and may become life-threatening. For instance, people may experience:
Edema (swelling)
Inflammation
Hemorrhage (bleeding)
Damage to the vessel wall
Thrombosis (blood clots)
In severe cases, acute kidney failure, stroke, and rhabdomyolysis (where the muscles break down) have also been reported.
While anti-venom is available, it is hard to diagnose a brown recluse spider accurately. That's because when you first get bit, you might not feel anything and in most cases, you don't see the spider that bit you. Plus, other conditions like bacterial or fungal infections or blood circulation issues can mimic a spider bite, which can often lead to a misdiagnosis.
Black Widow Spider Bite Symptoms
Black widow bites are not usually fatal, but they are extremely dangerous, especially to young children and older adults. Bites often occur while camping, hiking, gardening, or working in the garage. After just minutes, the area next to where the bite occurred may become painful, extremely red, swollen, or develop a cyst. Fang marks may even be evident.
As the venom spreads, you might develop latrodectism—an illness caused by the bite of Latrodectus spiders. This condition can cause:
Muscle pain, cramping, or rigidity
Abdominal tenderness
Vomiting
Rapid heart rate
Shallow breathing
Systemic (body-wide) pain
Elevated blood pressure
In severe cases, a black widow bite might also cause rhabdomyolysis (where the muscles break down) and myocarditis (heart inflammation). Sometimes the pain from a black widow bite is so painful it can be mistaken for appendicitis or a heart attack.
Fortunately, most people recover from a black widow bite without needing to use anti-venom. In fact, the risk of death is only about 1% or less—though the risk is much higher in kids and older adults.
Brazilian Wandering Spider Bite Symptoms
Brazilian wandering spiders—also known as armed spiders or banana spiders—have the largest venom glands of any spider. When these spiders were "milked" during one study, they produced as much as 8 milligrams (mg) of venom. This is a lot considering that 0.10 mg is enough to endanger human life.
The venom of this spider is a complex mixture of toxins, proteins, and peptides, which affects the ion channels and chemical receptors in your neuromuscular systems. This can cause a wide range of symptoms including:
Changes in heart rate and blood pressure
Abdominal cramping
Convulsions
Excessive sweating and salivation
The most notable reaction is that this spider's venom can cause painful and long-lasting erections in some people. For this reason, scientists have been conducting animal studies to determine if the spider's venom could be used to treat erectile dysfunction.
These spiders are rarely seen in the U.S., though some people speculate that they sometimes arrive in banana shipments. In Brazil, you can treat moderate to severe bites with anti-venom. In other milder cases, your treatment will depend on the exact symptoms you're experiencing.
Funnel-Web Spider Bite Symptoms
Funnel-web spiders, which are primarily found in Australia, are one of the most dangerous spiders in the world. These spiders are equipped with powerful, sharp fangs that can penetrate fingernails and even some shoes. These spiders are also one of the few types that are aggressive toward people.
A bite from a funnel-web spider is potentially life-threatening, so prompt anti-venom treatment is essential. Small kids and people with underlying medical conditions are particularly at risk of death or complications.
If you get bit by a funnel-web spider, you may experience:
Excessive sweating
Goosebumps
Hives
Agitation
Muscle twitches
Numbness in your mouth
Nausea or vomiting
Extra salivation
Watery eyes
These bites can even cause changes in blood pressure and heart rate and can sometimes lead to pulmonary edema (fluid in the lungs), particularly in children.
When to Contact a Healthcare Provider
See a healthcare provider if you get bitten by a venomous spider or are experiencing symptoms of a spider bite, This way, they can treat you for the bite before the venom starts to break down your skin or cause other serious complications. That said, most people will not know what type of spider bit them and will need to watch the area closely and monitor their symptoms. If your symptoms worsen, this is a good time to reach out for medical support.
You may require emergency medical attention. It's best to see a healthcare provider right away if you notice redness spreading out from the bite, fluid or pus draining from the area, an increase in pain, or discoloration in your skin. If you experience any of the following symptoms, get emergency medical treatment:
Excessive sweating
Weakness
Headache
Bullseye pattern or black scab on the skin
Numbness
Trouble breathing
Swollen or droopy eyelids
Rigid shoulder, chest, back, or stomach muscles
Questions to Ask Your Provider
When seeing a healthcare provider for a spider bite, come prepared with questions—especially because it's easy to forget what you want to ask when you are in pain. Here are some things to consider asking:
Is this a spider bite or something else?
What treatments are available to make my redness and swelling go away?
What symptoms should I watch for or be concerned about?
How long will my symptoms last?
Will there be any lasting damage from this bite?
A Quick Review
Most spiders do not attack people or bite them randomly. If you do get bitten by a spider, symptoms can range from mild to severe. Most people will experience mild pain, redness, itchiness, and swelling.
Symptoms progressing to something more significant like excessive sweating, weakness, dizziness, heart rate changes, and vision changes require immediate medical care.
Frequently Asked Questions
Can spider bites make you sick?
Although spider bites rarely cause serious problems, bites from a venomous spider like a brown recluse or black widow can cause you to feel sick.
How do you know if a bite is serious?
Spider bites by venomous spiders need to be treated right away. These types of bites can cause serious complications and even lead to death.
If you don't know what type of spider bit you, keep an eye on the area and monitor your symptoms. Increasing pain and worsening symptoms are the first indicators that a bite is serious and requires evaluation.
For more Health.com news, make sure to sign up for our newsletter!
Read the original article on Health.com.
