Involvement of the skin, eye and lymph nodes is also common. A variety of infectious and noninfectious agents have been implicated, but there is no proof that any specific agent is responsible. Cases of sarcoid have been described in both sexes, almost all ages, races and geographic locations. Females appear to be slightly more susceptible than males. There is remarkable diversity of the prevalence of sarcoidosis among certain ethnic and racial groups.
Blacks are often younger than whites with the disease.
In Europe, however, it affects mostly whites with higher prevalence in Sweden and among Irish females. It is most common between the ages of 20-40, but it can occur in children and in the elderly. Although it is rare in children, the disease is most frequent between 9 to 15 years of age. A small cluster occurs in children under age 4 years with one half less than 1 year of age. Patients with sarcoidosis display a mixture of depressed cell-mediated immunity and increased humoral system activity.