Hopkins 24/7

Back to ABC News

This Thursday at 10/9c

This content requires javascript and flash player version 8.

Johns Hopkins Symptoms and Remedies

Johns Hopkins Medicine

Close Article Browser

Chiggers

What is it?

Chiggers are the larvae of the harvest mite or red bug. The tiny larvae, measuring only about a third of a millimeter in length, inhabit grasses, weeds, shrubs, and brush, primarily in the southern United States (although they may be found as far north as Canada). They most often attach themselves to human hosts at the ankles and legs, since these are the parts of the body most commonly exposed to the low-lying vegetation where chiggers dwell. However, chiggers generally prefer warm, moist places and so may lodge in the groin area, the armpits, the crook of the elbow, beneath the waistband of clothing, or any region where clothing is tight.

Unlike ticks, chiggers do not feed off blood, nor do they spread disease. Instead, they inject enzymes into the host. Skin at the site of the chigger bite may react in a variety of ways. An allergic reaction is common, producing extremely itchy red patches. Blisters and swelling may also appear.

While serious diseases due to chigger bites are not a threat in the United States, minor secondary infections may ensue, especially if the sufferer scratches the itchy bumps until sores occur, which can then be invaded by bacteria. Although itching and discomfort may persist for weeks, chigger bites cause no permanent ill effects.

What Causes It?

  • Spending time in the woods or fields during the summer increases the risk of chigger bites.

Prevention

  • Use an insect repellent during outdoor summer activities.
  • When walking in the woods or fields, cover your legs completely by wearing long pants and tucking them into your socks or boots.

Diagnosis

  • Diagnosis is determined by visual observation and generally does not require a doctor.

How to Treat It

  • Try not to scratch chigger bites (scratching increases the risk of infection).
  • Calamine lotion, menthol or pramoxine anti-itch cream may be soothing.
  • At bedtime, take an antihistamine such as diphenhydramine, which can both relieve nighttime itching and help you sleep.
  • Over-the-counter corticosteroid creams (hydrocortisone) may alleviate itching. More potent hydrocortisone creams are available by prescription.
  • Your doctor may prescribe antibiotics to treat a secondary infection.

When to Call a Doctor

  • Call a doctor if you suffer an allergic reaction (such as hives) to chigger bites or if over-the-counter treatments fail to relieve severe itching or if you develop a secondary bacterial infection.