Chiggers
Harvest mite; Red mite
Chiggers are tiny, 6-legged wingless organisms (larvae) that mature to become a type of mite. Chiggers are found in tall grass and weeds. Their bite causes severe itching.
Chigger bites are caused by the larvae of the chigger. The bite produces blisters (vesicles) and bleeding into the skin (purpura). These bites itch intensely and are usually located on exposed areas of the skin where the chigger larvae have access. This photograph demonstrates vesicle formation following the bites.
Causes
Chiggers are found in certain outdoor areas, such as:
- Berry patches
- Tall grass and weeds
- Edges of woodlands
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 of chigger bites are:
- Severe itching
- Red pimple-like bumps or hives
Itching usually occurs several hours after the chiggers attach to the skin. The bite is painless.
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.
Exams and Tests
Your health care provider can usually diagnose chiggers by examining the rash. You'll likely be asked about your outdoor activity. A special magnifying scope may be used to find the chiggers on the skin. This helps confirm the diagnosis.
Treatment
The goal of treatment is to stop the itching. Antihistamines and corticosteroid creams or lotions may be helpful. Antibiotics are not necessary unless you develop a skin infection.
Possible Complications
A secondary infection may occur from scratching.
When to Contact a Medical Professional
Contact your provider if the rash itches very badly, or if your symptoms get worse or do not improve with treatment.
Prevention
Avoid outdoor areas that you know are contaminated with chiggers. Applying bug spray containing DEET to skin and clothing can help prevent chigger bites.
References
Diaz JH. Mites, including chiggers. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 295.
James WD, Elston DM, Treat JR, Rosenbach MA, Neuhaus IM. Parasitic infestations, stings, and bites. In: James WD, Elston DM, Treat JR, Rosenbach MA, Neuhaus IM, eds. Andrews' Diseases of the Skin. 13th ed. Philadelphia, PA: Elsevier; 2020:chap 20.
Version Info
Last reviewed on: 12/4/2022
Reviewed by: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
