Schnitzler syndrome is a rare auto-inflammatory disorder that causes long lasting (chronic) skin rashes and frequent (recurrent) fevers. The rashes feature red, swollen bumps known as hives (urticaria) that usually cover the torso, arms, and legs. Unlike most cases of hives, the bumps seen in Schnitzler syndrome are not itchy in most affected individuals. A fever may occur with the rash, but may also occur separately. The condition may also cause joint pain, bone pain, or muscle pain.
Symptoms of the disease usually appear around 50 years of age and the condition affects men slightly more often than women. Schnitzler syndrome usually does not cause serious issues, but affected individuals should have regular check-ups with a doctor, as many people may develop additional medical complications. About 50% of affected individuals do not have enough red blood cells (anemia), which are needed for transporting oxygen around the body. About 15% of individuals with Schnitzler syndrome develop a specific cancer of the white blood cells.
The exact cause of Schnitzler syndrome is unknown, but the disorder seems to be due to a response from the body’s immune system that causes recurrent episodes of inflammation (auto-inflammatory). The condition is considered in a person who has recurring episodes of hives and fevers. A doctor may also order a blood test to measure a protein called immunoglobulin M (IgM), which is usually elevated in people with Schnitzler syndrome. Treatment usually involves medications that help decrease the response of the immune system. If you have been diagnosed with this condition, talk with your doctor about all treatment options. Support groups can provide additional information and connect you with others affected by this condition.