How do I know I have it? (Symptoms and Diagnosis)

Insect Bites

Most people don’t notice that they’ve been bitten until some time later, when the itching starts. Depending on how allergic you are to the saliva deposited by the pest, you may get large welts or barely noticeable bumps (fig.1). Insect bites occasionally trigger severe allergic reactions (see anaphylaxis) which require immediate medical attention. If you have continual itchiness or a rash, you may have lice or scabies; these insects burrow into your skin.

Spider Bites

Spider bites (fig.1) may burn or hurt more than insect bites.While most spiders are not very poisonous, two North American varieties, the black widow and the brown recluse, can cause severe allergic reactions that can be fatal. Small children are at particular risk. The bite of a black widow is not painful and does not produce a noticeable sore, but within hours after being bitten, most people become very ill with muscle aches and cramps, swelling, vomiting and other severe symptoms. A bite from a brown recluse produces a red or purplish blister. Both bites require immediate medical intervention.

Insect Stings

A sting usually hurts more than a bite, especially when it’s a child who’s been stung. Normally the pain and swelling (fig.1) subsides within several hours and little treatment is needed. If the stinger is visible, the culprit was probably a honey bee; hornets or yellow jackets don’t leave stingers behind.

More extensive local reactions to stings are fairly common, however. You may notice that swelling extends over a large area and lasts up to a week. Fatigue and nausea may develop. If you have this type of reaction, see a doctor.

A very small proportion of those stung will experience an immediate and severe life-threatening reaction. Yellow jacket stings are most likely to cause this. Watch for hives, facial swelling, difficulty breathing, and profound weakness, indications of a life-threatening whole-body allergic reaction called anaphylactic shock.

What should I do? (Emergency Treatment)

Insect Bites

To soothe the bite, old-fashioned calamine lotion works well, especially if it contains a topical anesthetic. Lotions containing aloe, hydrocortisone, or diphenhydramine also work. Try not to scratch the bites; they can become infected.

If you have been bitten by a tick and it is still attached, remove it. Grasp it close to its head or mouth with tweezers or with the fingernails and pull it straight out with a slow and steady motion. If you have been bitten by a tick, save the tick after you have removed it and contact your health care provider to see if you are at risk for Lyme disease.

Spider Bites

Use cold, not heat to soothe a spider bite. Clean the bite and apply a thin layer of antibiotic ointment to prevent infection. If you’ve been bitten by a Black Widow, Brown Recluse or any spider you suspect may be poisonous, apply cool compresses to the bite and seek emergency medical assistance. If possible, kill the spider and bring it with you.

Insect Stings

If the stinger is present, gently remove it immediately, without pinching the venom sac. The stinger, once inside the skin, can continue to pump venom into the victim and if removed with tweezers pinching the sac, may pump more venom in. Remove the stinger by gently scraping it off with a sideways motion. Clean the wound to prevent infection, and apply ice or cool compresses to the site. Rest and watch carefully for signs of severe allergic reaction. An oral diphenhydamine may help control any redness or swelling around the site of the sting. If you’re having any trouble breathing, or if you develop itching, swelling, or a rash in areas that are not contagious from venom, call 911. If the person is allergic to the insect venom, a dangerous reaction may follow rapidly (within minutes, but occasionally delayed by up to two hours). If you notice that the redness is spreading after 24 hours, contact your health-care provider.

How dangerous is it? (Prognosis)

Insect bites are usually just an annoyance, though there is a small risk of infection from any break in the skin. Insects carry many serious infectious diseases. In particular, mosquitoes can carry malaria, encephalitis, Dengue fever, and Yellow fever. Ticks can transmit Lyme Disease, and fleas can carry human plague.

While severe reactions occur in less than one out of 10 people, until a person is stung, it is not known whether she will develop such an allergic response. People who have had severe reactions to stings are at increased risk for future reactions and should undergo venom sensitivity skin testing. Most importantly, ALWAYS keep doctor-prescribed medication for such allergies nearby.

How can I prevent it? (Prevention)

Around the House

Do not let children play in woodpiles, sheds, garages, and other spots where bugs may hide. Keep sleeping areas clear of spider webs. Consult with your veterinarian to keep pets as free of fleas as possible.

The Great Outdoors

Burn citronella candles outdoors in the summer. When traveling, get advice before journeying to areas where malaria and other infectious diseases pose health risks. When camping and hiking, wear protective clothing. Avoid bright colors to keep ticks away. Wear insect repellent, preferably containing the insecticide diethyltoluamide (DEET). The use of the insecticide DEET on children has been controversial, but the American Academy of Pediatrics says that is safe to use a solution containing up to 10% DEET on children. There are also herbal alternatives to DEET, such as citronella and eucalyptus.

First Aid

If your or any members of your family have known allergies to insects or spiders, your first aid kit should include all the medications recommended by your physician. Always have a kit available at home, outside, and when you travel.

Frequently asked questions (FAQ)

Q: Could I catch HIV from a mosquito?

A: No. HIV cannot survive or reproduce in insects. Biting insects do not inject their own blood, or the blood of a previously bitten person or animal into the next person bitten. They inject saliva.

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