What are the odds?

Here are some statistics about PRP.  

The chance of getting PRP is about 1 in 400,000 (Clinical Dermatology, By Richard Weller, John A. A. Hunter, John Savin, Mark Dahl).  That is about one person in a population the size of Malta.

(All other stats taken from DermNet NZ)

There are different types of PRP;

•       About 50% of those with PRP have Classical adult onset
•       About 5% of those with PRP have Atypical adult onset
•       About 10% of those with PRP have Classical juvenile onset
•       About 25% of those with PRP have Circumscribed juvenile
•       About 5% of those with PRP have Atypical juvenile onset
•       And there is also a HIV-associated variant

This table represents this split, with each square representing 5%:

The only types I could have are Classical adult onset or Atypical adult onset, so I think my chances of having Classical adult onset are 90.91% (10 out of 11) while my chances of having Atypical adult onset are about 9.09% (1 out of 11)

For those with Classical adult onset, 80% will have spontaneous remission within 3 years

For those with Atypical adult onset, the condition may persist for 20 years or more.