Physician Assistant Exam: How to Inspect for Spider and Insect Bites - dummies

Physician Assistant Exam: How to Inspect for Spider and Insect Bites

By Barry Schoenborn, Richard Snyder

It’s not nice to be bitten by insects or spiders — especially spiders. The Physician Assistant Exam (PANCE) will force you to face any fears you have to investigate the body for bites.


Lice (singular louse) are insects, and they can be anywhere on the body, especially the head. Some people may remember the elementary school nurse checking the kids for head lice. This affliction is spread from person to person.

It’s not a vector-associated disease like Lyme disease or Rocky Mountain spotted fever. Just the same, it’s extremely contagious. Risk factors include spending time in places where people are in close quarters and have poor hygiene. Outbreaks have occasionally occurred in schools and nursing homes, although nursing home outbreaks of lice are very uncommon.

Head lice attach to the hair follicles, often at the nape and behind the ears. They do bite and can leave small, red welts on the scalp. They lay their eggs, or nits, in the hair about 1/4 inch from the scalp. They are very hard to get rid of.

The treatment is meticulous hygiene and a medication called permethrin (Elimite). Clothes and bedding have to laundered, too, often repeatedly in very hot water, to kill the eggs. For head lice, you want to comb the hair with a very fine comb every few days when it’s wet. Doing so helps break up the eggs. Medicated shampoos are often used as well.

Anyone who may have come in contact with someone with head lice needs to change his or her clothes and launder them with hot water at the very least, because lice can be on the clothes.

How to treat the mite-y scabies

Scabies (the seven-year itch) is a skin condition that, like lice, is transmitted from person to person. Scabies is transmitted by the mite Sarcoptes scabiei (the “itch mite”). Outbreaks have occurred in nursing homes and schools, where individuals are in a lot of close contact.

On examination, look for evidence of the mite that has burrowed under the skin. You may see small pustular and papular lesions or what looks like tracks made in the skin. You can find them on the extremities, especially in the interdigital areas of the fingers and toes. Treatments include lindane, permethrin, and the antiparasite medication ivermectin (Stromectol). People in contact with the affected person should also receive treatment.

Spider bites

Spider bites can look like insect bites and stings. The more dangerous spider bites are often necrotic, which can cause confusion. For the most part, spider bites in the United States are deadly only if they’re from a black widow or brown recluse spider. You need to have a high index of suspicion that your patient was in fact bitten by one of these deadly spiders:

  • Brown recluse spider bites may occur when cleaning out storage areas, leaf debris, or wood piles, or the patient may not recall when he or she was bitten. Within 24 hours after the bite, the area surrounding the bite site typically turns a reddish-blue color and may develop a blister. Necrosis follows.

  • Black widow spider bites cause pain at the envenomation site, nausea, vomiting, and abdominal rigidity, along with other neurological effects.

Treatment of a bite from the black widow or brown recluse includes cleaning the area with soap and water. If the bite is on an extremity, the person should elevate the arm or leg and tie a tourniquet above the bitten area to prevent the venom from spreading. Getting the person to an emergency room pronto is mandatory. Talking with a toxicology expert is important. The affected person needs antivenin.