The onset of the disease is usually between 5 and 15 years of age. The frequency and duration of attacks varies greatly with attacks lasting 24 h to 10 days and varying in frequency from 1 per year to 1 per fortnight.
Possible features include:
- fever: is present during most attacks
- abdominal pain: in 95% of cases. The pain usually begins in one quadrant and spreads to effect the whole abdomen. Often the abdomen is also distended.
- chest pain: 75% of patients develop acute pleuritic chest pain with or without abdominal pain. The chest pain is usually unilateral and associated with a friction rub, decreased breath sounds, or a pleural effusion.
- joint pain: may involve one or several joints. Effusions are common. Large joints are most often involved. There are no specific radiological findings.
- skin manifestations: in approximately 25% of patients. There may be areas of a painful, erythema that are usually seen on the lower legs. They may occur with or without abdominal or chest pain.
- there has been other involvement of serosal membranes reported.