Toxic synovitis

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Toxic synovitis is a condition affecting children that causes hip pain and limping.

Alternative Names

Synovitis - toxic; Transient synovitis


Toxic synovitis occurs in children before puberty. It is a type of arthritis of the hip. Its cause is not known. Boys are affected more often than girls.


Symptoms may include:

  • Hip pain (on one side only)
  • Limp
  • Thigh pain, in front and toward the middle of the thigh
  • Knee pain
  • Low-grade fever, less than 101°F (38.33°C)

Aside from the hip discomfort, the child does not usually appear ill.

Exams and Tests

Toxic synovitis is diagnosed when other, more serious conditions have been ruled out, such as:

Tests used to diagnose toxic synovitis include:

Other tests that may be done to rule out other causes of hip pain:


Treatment often includes limiting activity to make the child more comfortable. But, there is no danger with normal activities. The health care provider may prescribe nonsteroidal anti-inflammatory medicines (NSAIDS) to reduce pain.

Outlook (Prognosis)

The hip pain goes away within 7 to 10 days.

Possible Complications

Toxic synovitis goes away on its own. There are no expected long-term complications.

When to Contact a Medical Professional

Call for an appointment with your child's provider if:

  • Your child has unexplained hip pain or a limp, with or without a fever
  • Your child has been diagnosed with toxic synovitis and the hip pain lasts for longer than 10 days, the pain gets worse, or a high fever develops


Horowitz R. Pediatric orthopedic emergencies. In: Adams JG, ed. Emergency Medicine: Clinical Essentials. 2nd ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 25.

Sankar WN, Horn BD, Wells L, Dormans JP. The hip. In: Kliegman RM, Stanton BF, St Geme JW III, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 678.

Version Info

  • Last reviewed on 7/13/2015
  • C. Benjamin Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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