Bed bugs and spiders don’t seem to have much in common. But they share one trait: They bite. However, many spider bites can look like bed bug bites. So how to tell them apart? We’ll explain how to identify and treat bed bug and spider bites — and when you need to get medical help.
Can Spider Bites Look Like Bed Bug Bites?
At first glance, it can be hard to tell spider bites from bed bug bites. But there are a few differences.
What Bed Bug Bites Look Like
Generally, bed bug bites tend to show up in lines or clusters and are itchy, burning, swollen bumps or welts with a dark spot in the center. (On light skin, the bumps look red; on dark skin, they may be purple or faint pink). They may not show up immediately or at all: Some people have no response to bed bug saliva, which causes the reaction.
What Spider Bites Look Like
Most spider bites are singular, as opposed to bed bug bites. While many spiders inject venom, most bites are not serious. According to Seattle Children’s Hospital, you’ll get an itchy, red, swollen bump that may hurt for a day or so. On dark skin, the redness may be faint or reddish-brown.
However, there are spiders whose venom produces serious reactions. The two best-known:
Black widow spiders: Black widow bites can start with a sharp pinprick of pain, then numbness at the site. Other symptoms can set in quickly — within a couple of hours and include:
- Difficulty breathing
- Swelling around the eyes
- Headache
- Increased saliva
- Nausea and vomiting
- Painful muscle cramps and stiffness
- Profuse sweating
Brown recluse spiders: You may not notice a brown recluse bite at first, but pain may increase over the next eight hours. Other symptoms include.
- Puncture holes
- A small white blister with a red ring around it
- Skin that turns blue or purple and progresses into an open sore
- Fever
- Chills
- Rash
- Upset stomach
Where Do Bed Bugs Bite?
Any part of you that touches an infested mattress or other site is fair game. Commonly, you’ll see bites here:
- Face
- Neck
- Legs and ankles
- Arms and hands
Where Do Spiders Bite?
Spiders bite in self-defense — usually if they’re trapped between you and another object. So, you can be bitten just about anywhere on your body. Some common places:
- Hands and arms
- Legs
- Feet
Where Do Bed Bugs and Spiders Hide?
Bed bugs and spiders prefer quiet spots, preferably in easy reach of a food source. (That would be you for bed bugs; spiders prefer insects.)
Bed Bugs
While the first place to look is your mattress, box spring, and bedding, you may find bed bugs in other places, too:
- Seams of upholstered furniture
- Inside drawers
- Electrical receptacles
- Wall hangings
- Loose wallpaper
Spiders
In general, inspect anything stored in a basement, garage, shed, or attic. Some common areas in which you’ll find spiders:
- Bedding
- Clothing (Note: If you keep your yard shoes in the garage, shake them out.)
- Boxes
- Piles of firewood or other lumber
- Patio furniture
- Flower pots or gardening equipment
How to Treat Bed Bug and Spider Bites
A bed bug bite and a spider bite may have similarities, but they can produce very different reactions. (And spider bites can produce different reactions, depending on which species bit you.) So treatment differs.
Bed Bug Bites
Bed bug bite treatment is mostly about stopping the itch. Some things to try:
- Wash with soap and lukewarm water
- Cold compresses
- A baking soda paste
- An OTC hydrocortisone cream
- An OTC antihistamine
When to Seek Medical Help
Call your doctor if you have these symptoms:
- Severe itching that doesn’t get better after treatment
- Any sign of infection — fever, pus, pain, spreading redness
- No improvement after a week
When to Seek Emergency Medical Help
In some people, bed bug bites can cause a serious allergic reaction. Get immediate help for these symptoms:
- Fever
- Chills
- Difficulty breathing
- Swelling of the throat or mouth
Spider Bites
- Wash with soap and lukewarm water.
- After washing, apply an antibiotic ointment to protect against infection.
- Apply cold compresses.
- Take acetaminophen or ibuprofen for pain.
- If the spider bite is on an arm or leg, elevate it to reduce swelling.
When to Seek Medical Help
Call your doctor if you see these symptoms:
- Pain that lasts for more than two days
- Signs of spreading redness
- Skin damage or blisters
When to Seek Emergency Care
If you know or suspect that you have been bitten by a black widow or brown recluse spider, go to the emergency room immediately. Symptoms that need quick attention:
- Fever
- Vomiting
- Trouble breathing
- Weakness
- Severe muscle cramps
Bed Bug Bites vs. Spider Bites on Pets
Both bed bugs and spiders will bite your pets. Bed bugs can hide in Bella or Tiger’s bedding or their favorite sleeping spots.
Spider bites aren’t as common in cats, since they have thicker skin. But Bella and Tiger can unwittingly stick a nose or a paw into a spider’s lair. Tiger could bat around a spider or pounce on it. Or eat it. So here’s what to look for:
Bed Bug Bites
Unlike fleas, bed bugs don’t burrow in dog or cat fur, though they can bite around the head and neck. You’ll usually see red bumps along their belly and legs. Treatment is about relieving the itch: Try cold compresses and soothing shampoos. Talk to your vet about antihistamines or topical steroids.
What to watch for: Scratching can lead to a secondary infection. Also, bites can cause a serious allergic reaction. Call your vet if you see these symptoms:
- Swelling around the eyes, ears, and face
- Vomiting
- Diarrhea
- Difficulty breathing
Spider Bites
Non-dangerous bites: Like bed bug bites, these may present as red, itchy bumps. Treatment can include cold compresses and baking soda pastes. You may need a collar (better known as “the cone”) to prevent excessive licking and scratching.
What to watch for: Dogs and cats can have allergic reactions to many insects, including spiders. Symptoms include:
- Hives
- Swelling of the face or muzzle
- Vomiting
- Difficulty breathing
Black widows: If your dog or cat is bitten by a black widow (or if you even suspect it), this is a medical emergency. Black widow bites can be fatal to cats. The bite is painful but can be hard to find. Symptoms can progress rapidly — more so in cats. They include:
- Muscle rigidity and tremors
- Severe pain (Your pet may whimper, cry, or howl.)
- Stumbling
- Difficulty breathing
- Seizures
Brown recluse: While many brown recluse bites may heal on their own, in severe cases, your pet will need medical care. Dogs may lay on a brown recluse — most bites are on the legs. Cats are bitten when they bat or pounce on one.
Like in humans, bites aren’t painful at first. But if left untreated, within two to eight hours, the toxins will begin to kill skin around the bite, and the dead tissue can make your pet very ill.
And yes, cats do eat spiders. (They’re not picky; they’ll also eat flies or other insects.) If it’s a non-dangerous spider, Tiger may get an upset stomach but likely will be fine. However, if the spider bites Tiger’s tongue or throat on the way down, get him to the vet; swelling in these areas can affect his airways.
Note: If Tiger does eat a black widow or brown recluse, get him to the vet immediately, especially if there’s a chance he was bitten.
FAQ
Does an Insect Bite With a Red Ring Come From a Bed Bug or a Spider?
It is unlikely that the bite is from a bed bug, though spreading and redness can be a sign of a skin infection. But a recluse spider bite can leave a red ring surrounding skin that has turned dark blue or purple. If that describes the bite, get immediate medical help.
Other possibilities:
Fleas: Flea bites can be small, itchy bumps surrounded by a ring of inflammation.
Ticks: Ticks carry Lyme disease, and a rash that looks like a growing bulls-eye can be an early sign of the illness. Get medical help quickly.
I Have Bites, but There are No Signs of Bed Bugs. What’s Biting Me?
If you’ve done a thorough search and found no sign of bed bugs, then it’s time to look at other possibilities.
Mosquitoes: Mosquito bites usually leave an itchy, pink bump. Check inside and outside for areas where mosquitoes can get in or breed.
Spiders: Most non-dangerous spider bites can resemble bed bug bites. Check areas where spiders like to hide.
Fleas: Flea bites can be hard to distinguish from bed bug bites. Check your bedding, furniture, and carpets. Watch your pets for signs of excessive scratching.
Note: If bites happen during warm weather, it’s possible that you may have chigger bites. These insects will attach themselves to your clothes, then move in to bite.
Do Spiders Eat Bed Bugs?
Yes, some species of spiders do eat bed bugs. Among them are the wolf spider, the jumping spider, and the European Thanatus flavidus, all of which hunt prey rather than spin webs. Take note that battling a bed bug infestation would take a lot of spiders, which might present other problems.
When to Call the Pros
Removing bed bugs or spiders can be difficult. A DIY approach may not reach all the spots where bed bugs and spiders hide. If the spider infestation includes the black widow or brown recluse, you may risk a trip to the ER. A local pest control company has pros who can find and safely remove bed bugs or spiders from your home.
Additional sources:
Main Image Credits:
Spider Bites: S. J. Pyrotechnic / Flickr / CC BY-SA 2.0
Bed Bug Bites: Oliver Arend / Wikimedia Commons / CC BY-SA 3.0
