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Fleas

Fleas are small insects that feed on the blood of humans, dogs, cats, and other warm-blooded animals.

Causes

Fleas prefer to live on dogs and cats. They may also be found on humans and other warm-blooded animals.

Pet owners may not be bothered by fleas until their pet has been gone for a long period of time. Fleas look for other sources of food and begin to bite humans. Bites often occur around the waist, ankles, armpits, and in the bend of the elbows and knees.

Symptoms

Symptoms of flea bites include:

  • Small red bumps, often three bumps together, that are very itchy
  • Blisters if the person has an allergy to flea bites
  • Located most often on the arms, legs and places where clothes fit close to the body, such as the thighs and waist

Exams and Tests

Usually, a diagnosis can be made when the health care provider examines the skin where the bites are. Questions may be asked about contact with animals such as cats and dogs.

In rare cases, a skin biopsy is done to rule out other skin problems.

Treatment

You can use an over-the-counter 1% hydrocortisone cream to relieve itching. Antihistamines you take by mouth may also help with itching.

Possible Complications

Scratching can lead to a skin infection.

Prevention

Prevention may not always be possible. The goal is to get rid of the fleas. This can be done by treating your home, pets, and outside areas with chemicals (pesticides). Small children should not be in the home when pesticides are being used. Birds and fish must be protected when chemicals are sprayed. Home foggers and flea collars do not always work to get rid of fleas. If home treatments do not work, you may need to get professional pest control help.

Alternative Names

Pulicosis; Dog fleas; Siphonaptera

References

Habif TP. Infestations and bites. In: Habif TP, ed. Clinical Dermatology. 6th ed. Philadelphia, PA: Elsevier; 2016:chap 15.

James WD, Berger TG, Elston DM. Parasitic infestations, stings, and bites. In: James WD, Berger TG, Elston DM, eds. Andrews' Diseases of the Skin: Clinical Dermatology. 12th ed. Philadelphia, PA: Elsevier; 2016:chap 20.

Review Date 10/25/2016

Updated by: David L. Swanson, MD, Vice Chair of Medical Dermatology, Associate Professor of Dermatology, Mayo Medical School, Scottsdale, AZ. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.