Slideshow: Black Widow Spider vs. Brown Recluse Spider
The following 6 slides contain severe case images. If you are sensitive
to images of this nature you can skip these slides by clicking on the link below.
Click here to skip ahead
More Slideshows from eMedicineHealth
Watch and learn from these additional pictures slideshows.
Healthy Eating in Restaurants
Black Widow Spider vs. Brown Recluse Spider
The majority of spiders found in the US are harmless. The two most common exceptions are the black widow spider and the brown recluse spider, which are both dangerous to humans. The black widow and brown recluse spiders are more common in the southern states of the US and prefer warm, dry climates as well as undisturbed areas such as basements, closets, woodpiles, attics, or under sinks.
What types of dangers would you expect from a black widow bite?
The black widow spider produces a protein venom that affects the victim's nervous system. This neurotoxic protein is one of the most potent venoms secreted by an animal. Some people are slightly affected by the venom, but others may have a severe response.
Black widow victims may experience these symptoms:
Symptoms usually start within 20 minutes to one hour after the bite. Localized or generalized severe muscle cramps, abdominal pain, weakness, and tremor may occur. In severe cases nausea, vomiting, faintness, dizziness, chest pain, and respiratory difficulties may follow.
What type of dangers would you expect from a brown recluse spider?
The brown recluse venom is extremely poisonous, even more potent than that of a rattlesnake. Yet recluse venom causes less disease than a rattlesnake bite because of the small quantities injected into its victims. The venom of the brown recluse is toxic to cells and tissues.
Brown recluse victims may experience these symptoms:
Brown recluse spider bites often go unnoticed initially because they are usually painless bites. Occasionally, some minor burning that feels like a bee sting is noticed at the time of the bite. Symptoms usually develop two to eight hours after a bite. Victims may experience severe pain at the bite site after about four hours, as well as severe itching, nausea, vomiting, fever, and muscle pain (myalgias).
Who is the black widow spider?
The black widow is a medium-sized spider whose body is about a half-inch long. The name is derived from the mistaken belief that the female invariably kills the male after mating. Five species are common to the US, with two of them being the most common: the southern black widow and the northern black widow.
Who is the southern black widow spider?
The southern black widow has the shiny, black, globular abdomen with the distinctive red hourglass on the underside.
Who is the northern black widow spider?
The northern black widow has a row of red spots down the middle of the upper surface of its abdomen and two crosswise bars on the undersurface. Just to make things interesting, the markings can also be yellow or white, and the spider itself may be brown or have red legs.
Who is the brown recluse spider?
Brown recluse spiders are native to the Midwestern and Southeastern states, although they have been found in other areas. Documented populations of brown recluse spiders outside these areas are rare. Most false sightings are due to confusion with one of the 13 other species found in the same family.
Who are the non-brown recluse spiders?
The most common non-brown recluse spiders are the desert recluse found in Texas, Arizona, and California, and the Arizona recluse. No deaths have ever been reported from non-brown recluse spiders. Bites from these cousins produce mild to moderate local skin disease.
Who is the brown recluse spider?
Brown recluse spiders are notable for their characteristic violin pattern on the back of the cephalothorax-the body part to which the legs attach. The violin pattern is seen with the base of the violin at the head of the spider and the neck of the violin pointing to the rear. These small non-hairy spiders are yellowish-tan to dark brown in color with darker legs. Their legs are approximately one inch in length. The name of the genus, Loxosceles, means "six eyes." Most other spiders have eight eyes. Yet this unique feature of the brown recluse is lost on the casual observer because the eyes are too small to be seen with the naked eye.
What are the habits of a black widow?
Black widow spiders are nocturnal (are active at night). They prefer dark corners or crevices. They are said to avoid human dwellings, but you can find them in such areas as outhouses and garages. Only the female black widow bites humans, and she bites only when disturbed.
What are the Habits of a Brown Recluse Spider?
These spiders are not aggressive and bite only when threatened, usually when pressed up against the victim's skin. They seek out dark, warm, dry environments such as attics, closets, porches, barns, basements, woodpiles, and old tires. Its small, haphazard web, found mostly in corners and crevices, is not used to capture prey but serves as the spider's daytime retreat while it roams at night searching for insect prey. Most brown recluse bites occur in the summer months.
What does a black widow spider bite look like?
The first symptom is acute pain at the site of the bite, although there may only be a minimal local reaction. A black widow spider bite is said to feel like a pinprick, and sometimes double fang marks may be seen at the location of the bite. The severity of the reaction depends on the age and physical condition of the person bitten. Children and the elderly are more seriously affected than young adults. Blood pressure and heart rate may be elevated.
Progression of black widow spider bite.
Several hours after the initial bite of the black widow spider, the bite injury progresses and swells as shown on the left. According to this victim, two days after the bite, redness and swelling continued past the elbow and halfway down his forearm. Eight days after the bite, the swelling had subsided, the bite opened, and the infection was nearly gone as shown in the right image.
What does a brown recluse spider bite look like?
Initially the bite site is mildly red and upon close inspection may reveal fang marks. Most commonly, the bite site will become firm and heal with little scaring over the next few days or weeks. Occasionally, the local reaction will be more severe with erythema (redness) and blistering, sometimes leading to a blue discoloration, and ultimately leading to a necrotic lesion (tissue death) and scaring. In the example shown here, the bite area swelled to the size of a quarter within an hour and by the end of the first day continued to swell and turned blue and dark red.
Progressed brown recluse spider bite (day three)
In some cases local reaction will be more serious, leading to necrosis (death) of skin and subcutaneous fat. This image shows the progressed state of the same patient after the third day and the initial stages of skin necrosis.
Progression of brown recluse spider bite (day nine)
After the ninth day, severe destructive necrotic lesions with deep wide borders result. The patient endured eight days with an open wound to drain the spider's toxins and needed intravenous antibiotics and pain medication almost 24 hours per day.
Progression of brown recluse spider bite (day 38)
Eleven days after the bite, a five inch wide area of dead tissue was excised, necessitating skin grafting. This image shows the skin graft results 38 days after the bite.
Progression of brown recluse spider bite (10 months)
View of healed brown recluse wound approximately 10 months after the bite.
When should I seek medical care for a black widow spider bite?
In general, treatment for serious reactions to a black widow spider's bite will be beyond the scope of most medical offices and urgent care centers. Pain relief may require the use of narcotics and antivenin (antitoxin to counteract the effects of the spider venom). The decision to seek emergency care is usually easy and should be made early. If the person who was bitten by a black widow spider has more than minor pain or has whole-body symptoms, seek care at a hospital's Emergency Department.
Are there self-care home treatments for a black widow spider bite?
For minor bites, the options for home care are somewhat limited. Both cold and warm compresses have been recommended, as have hot baths. Certainly, a hot bath would seem to be of value because the pain is due primarily to muscle spasm. Obviously, over-the-counter pain relievers such as acetaminophen and ibuprofen may be of value in mild cases. Folk remedies have not proven to work.
When should I seek medical care for a brown recluse spider bite?
If you think you or someone you know has been bitten by a brown recluse spider, then the individual should be seen by a doctor that day. If possible, bring the spider in question to the doctor's office. Identification of the spider is very helpful in making the correct diagnosis. If the patient is unable to be seen by a doctor that day, seek care at a hospital's Emergency Department.
Are there self-care home treatments for a brown recluse spider bite?
Home first aid care is simple. This self-care should not replace a visit to a doctor or Emergency Department. Apply ice to decrease pain and swelling. Elevate the area if possible above the level of the heart. Wash the area thoroughly with cool water and mild soap. Avoid any strenuous activity because this can spread the spider's venom in the skin. Use acetaminophen for pain relief.
Whose bite packs a bigger sting?
Both the black widow and the brown recluse spider emit powerful venom which could in some cases become deadly to the individual. Both bites are painful; however, the brown recluse takes the match in severe cases capable of causing blistering blue discoloration, ultimately leading to destructive necrotic lesions with deep wide borders and scarring. Ultimately, be cautious of both spiders and seek medical care if bitten!
More Reading on Spiders & Insects