Cryopyrin-Associated Autoinflammatory Syndromes (CAPS)


Cryopyrin-associated autoinflammatory syndromes (CAPS) are rare diseases related to a defect in the cryopyrin protein. CAPS diseases usually start in very young children. CAPS include Neonatal Onset Multisystem Inflammatory Disease (NOMID), Muckle-Wells Syndrome (MWS) and Familial Cold Autoinflammatory Syndrome (FCAS). CAPS is caused by a gene mutation that may be inherited from only one parent. The gene mutation causes a defect in the cryopyrin protein, which helps control inflammation. Males and females from all ethnic groups may have CAPS.

What Are the Signs/Symptoms?

CAPS causes recurrent episodes of fever, hive-like rash, joint pain and swelling, red eyes, headache, and if untreated, deafness or amyloidosis (i.e., increased protein deposits in major organs that can result in organ failure).

NOMID causes fever and inflammation in multiple organs. It may present in newborns with a fever and hive-like rash that does not itch. Patients may have chronic meningitis, causing headaches, blindness, hearing loss and neurologic problems. Children with NOMID develop pain and swelling in large joints such as the knee. Growth delay may occur.

Signs of Muckle-Wells include episodic fever, chills, rash, red eyes, joint pain and severe headaches with vomiting. Episodes last from one to three days. Children may develop partial or total hearing loss by their teen years.

Children with Familial Cold Autoinflammatory Syndrome react to cold exposure with a hive-like rash, as well as fever, chills, nausea, severe thirst, red eyes, headaches and joint pain. Episodes may last for a day.

What Are Common Treatments?

A pediatric rheumatologist can diagnose CAPS with physical examination and genetic testing. Some patients may have normal genetic tests and skin biopsy, eye exam, hearing tests, lumbar puncture to obtain fluid from the spine, and imaging of the brain or inner ears may be needed. Medications that target interleukin-1 are very effective CAPS treatments. These are injections and include anakinra (Kineret), rilonacept (Arcalyst) and canakinumab (Ilaris). Early diagnosis and treatment may prevent irreversible damage to bone, brain, eyes and ears. Physical therapy and splints may help children with joint deformities. Surgery is occasionally needed. Children with hearing loss may need hearing aids.

Living with CAPS

Children whose CAPS is not treated may have severe episodes that lower their quality of life. Untreated patients may develop organ failure due to amyloidosis. Children may need psychological support to cope with having a chronic illness. Children with FCAS may need to live in mild climates and avoid places with very cold air conditioning. With effective treatments, children may be able to control CAPS symptoms and lead near-normal lives.

Updated February 2023 by Mohammad Ursani, MD, and reviewed by the American College of Rheumatology Committee on Communications and Marketing.

This information is provided for general education only. Individuals should consult a qualified health care provider for professional medical advice, diagnosis and treatment of a medical or health condition.

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