Prevalence and Incidence of Dermatostomatitis, Stevens Johnson type
Ophanet, who are a consortium of European partners,
currently defines a condition rare when if affects 1 person per 2,000.
They list Dermatostomatitis, Stevens Johnson type as a "rare disease".
More information about Dermatostomatitis, Stevens Johnson type is available from Orphanet
About prevalence and incidence statistics:
The term 'prevalence' of Dermatostomatitis, Stevens Johnson type usually refers to the estimated population
of people who are managing Dermatostomatitis, Stevens Johnson type at any given time.
The term 'incidence' of Dermatostomatitis, Stevens Johnson type refers to the annual diagnosis rate,
or the number of new cases of Dermatostomatitis, Stevens Johnson type diagnosed each year.
Hence, these two statistics types can differ:
a short-lived disease like flu can have high annual incidence but low prevalence,
but a life-long disease like diabetes has a low annual incidence but high prevalence.
For more information see about prevalence and incidence statistics.