Causes

Fleas prefer to live on dogs and cats, but may also be found on humans and other available animals.

Pet owners may not be bothered by fleas until their pet is gone for a long period of time, and the fleas must find another place to go. This is when they begin to bite humans. Bites often occur around the waist, ankles, armpits, and in the bend of the elbows and knees.

Symptoms

• Hives
• Itching (can be severe, and may be all over or just where the rash is located)
• Rash with small bumps that itch and may bleed
  • Located on the armpit or fold of a joint (at the elbow, knee, or ankle)
  • The amount of skin affected increases over time (enlarging skin rash or lesion) or the rash spreads to other areas
  • When pressed the area turns white (blanches to touch)
• Skin folds, such as under the breasts or in the groin may be affected (intertrigo)
• Swelling only around a sore or injury

Note: Symptoms often begin suddenly (within hours).

Exams and Tests

No testing is necessary.

Treatment

The goal of treatment is to get rid of the fleas by treating the home, pets, and outside areas with insecticide. Small children should not be in the home when insecticides are being used. Birds and fish must be protected during spraying. Home foggers and flea collars do not always work. If home treatments do not work, professional extermination may be needed.

If flea bites occur, an over-the-counter 1% hydrocortisone cream can help relieve itching.

Outlook (Prognosis)

Getting rid of fleas can be difficult and takes persistence.

Possible Complications

Scratching can lead to a skin infection.

Prevention

Prevention may not be possible in all cases. Use of insecticides may be helpful if fleas are common in your area. Professional extermination may be necessary in some cases.

Alternative Names

Dog fleas; Siphonaptera

References

Habif TM. Infestations and bites. In: Habif TP, ed. Clinical Dermatology. 5th ed. Philadelphia, Pa:Mosby Elsevier;2009:chap 15.

Updated: 4/28/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.