Drexel University College of Medicine

Diseases and Conditions

Chiggers

Definition

Chiggers are tiny, six-legged wingless organisms (larvae) that grow up to become a type of mite. Chiggers are found in tall grass and weeds. Their bite causes severe itching.

Alternative Names

Harvest mite; Red mite

Causes, incidence, and risk factors

Chiggers are found in certain outdoor areas, such as berry patches, tall grass and weeds, and woodland edges.

Chiggers bite humans around the waist, ankles, or in warm skin folds. Bites commonly occur in the summer and fall months.

Symptoms

The main symptoms are:

• Severe itching
• Red pimple-like bumps or hives

Itching usually occurs several hours after the chiggers attach to the skin.

A skin rash may appear on the parts of the body that were exposed to the sun. It may stop where the underwear meets the legs. This is often a clue that the rash is due to chigger bites.

Signs and tests

A doctor can diagnose chiggers by examining the rash.

Treatment

The objective of treatment is to relieve the itching. Antihistamines and corticosteroid creams or lotions may be helpful.

Expectations (prognosis)

This condition heals itself without treatment.

Complications

Secondary infection may follow intense scratching as a complication.

Calling your health care provider

Call for an appointment with your health care provider if the rash itches very badly, or if symptoms get worse or do not improve with treatment.

Prevention

Avoid outdoor areas contaminated with chiggers, if known. Applying bug spray containing DEET to skin and clothing can help prevent chigger bites.

References

Diaz JH. Mites (including chiggers). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 296.

Schlossberg D. Arthropods and leeches. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 380.

Physician Reference

International Classification of Diseases, 9^th Revision (ICD9)

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