Probably no creature on earth can cause as much torment for its size than the tiny chigger. Also known as Trombicula alfreddugesi, these tiny six-legged chigger larvae attack anyone in low, damp areas where vegetation is rank, such as woodlands, along lakes and streams and even in drier places where vegetation is low like lawns, golf courses, and parks. They are most numerous in early summer when grass, weeds and other vegetation are heaviest. Chiggers do not burrow into the skin but insert their mouthparts in a skin pore or hair follicle. Their bites produce small, reddish welts on the skin accompanied by intense itching as irritating as acute cases of poison ivy. These symptoms often are the only way of learning that an outdoor area is infested since chiggers are so small that most cannot be seen without a magnifying glass.

Identification

Chigger mites are about 1/20 inch long, usually bright red, have hairy bodies, and travel rapidly. The larval stage has three pairs of legs whereas the nymph and adult stage have four pairs of legs. There is a marked constriction in the front part of the body in the nymph and adult stage. Larvae are orange, yellow or light red and about 1/150 to 1/120 inch in diameter. Eggs are globular-shaped.

Bites

According to William F. Lyon at the University of Ohio Entomology department, the preferred feeding locations on people are parts of the body where clothing fits tightly over the skin such as around the belt line, waistline, under girdles and under socks, or where the flesh is thin, tender or wrinkled such as the ankles, in the armpits, back of the knees, in front of the elbow or in the groin. Only the larvae are known to attack humans. The adult and nymph stages are mainly plant eaters. Chigger larvae do not burrow into the skin or suck blood. They pierce the skin and inject into the host a salivary secretion containing powerful, digestive enzymes that break down skin cells that are ingested (tissues become liquefied and sucked up). Also, this digestive fluid causes surrounding tissues to harden, forming a straw-like feeding tube of hardened flesh from which further, partially-digested skin cells may be sucked out. After a larva is fully fed in four days, it drops from the host, leaving a red welt with a white, hard central area on the skin that itches severely and may later develop into dermatitis. Any welts, swelling, itching, or fever will usually develop three to six hours after exposure and may continue a week or longer. If nothing is done to relieve itching, symptoms may continue a week or more. Scratching a bite may break the skin, resulting in secondary infections. Chiggers are not known to transmit any disease in the United States. However, in Asia and the Pacific, chiggers can transmit disease called scrub typhus.

Prevention

Chigger larvae can penetrate many types of clothing, but high boots and trousers of tightly woven fabric tucked into stockings or boots help deter them. Before going into an area where chiggers may be present, protect yourself by using a repellent such as DEET or Permethrin available at many drugstores or hardware stores. DEET-based repellents are effective for only a few hours, whereas Permethrin-based repellents are for use only on clothing and effective for several days.

Apply the repellent to both the skin and clothing, especially on hands, arms, or legs, if uncovered, and to clothing openings at cuffs, neck, waistband, and upper edges of socks. Keep moving since the worst chigger infestations occur when sitting or laying down in a sunny spot at midday with temperatures above 60°F. If possible, stick to roads and trails.

Another preventative method is to buy 100 percent sulfur powder at a pharmacy. Before heading outside, sprinkle sulfur powder around your ankles, waist and underarms. This is reported to be remarkably effective against chiggers.

Treatment

Undress immediately after your exposure to chigger habitat and take a warm, soapy shower. Pay special attention to scrubbing the areas around your ankles, waistline, underarms and anywhere there are folds or creases in your skin. Wipe the "chigger hot spots" (ankles, waistline) down with a bit of rubbing alcohol. Have someone examine you for chiggers. Remember that they're extremely tiny, but if you find one soon after being outside, you can remove it before it starts biting. Wash the clothes you wore outside before putting them on again.

Topical Cortisone creams can be very helpful to reduce the itching. Chigger mites frequently lay eggs underneath the skin, and Lindane (Kwell), which is also used for head lice, can be very effective, as well as asking your healthcare provider for Permethrin (Elimite). These medications usually take care of the chiggers fairly quickly.

The only ultimate cure is time, since there is nothing you can do to dislodge the chigger's feeding tube, the true cause of your itch. You must simply wait until your body breaks down and absorbs the foreign object.

In the meantime, local anesthetics such as benzocaine, camphor-phenol and ammonium hydroxide may provide you with several hours of comfort at a stretch. Over-the-counter creams can also help. In rare cases, some people are allergic to chigger bites and require prescription medications from their doctor.

The popular home remedy for which there is little justification is to dab nail polish on the welt. This cannot "smother" the chigger because it has not burrowed into your skin, and it was probably scratched off long ago. The only benefit to applying a thick coat of nail polish is that it helps to remind you not to scratch the bite.

There is no creature alive that can cause more torment for its size than the chigger. By at least knowing what your attacker is and how it operates, you can itch less this summer and get more enjoyment from your outdoor activities.