"In the meantime, immerse your nose continually in ice cold water."
-- Professor H Spleen (DP3)
Mr Howland Coopey wrote to the Prophet describing symptoms of a green and purple rash coupled with sparks when he sneezed. Professor Helbert Spleen of St. Mungo’s Hospital dismissed his fears and advised that the symptoms would clear up by themselves (DP3).
While Professor Spleen states in his reply that Mr Coopey's dragon pox symptoms will disappear on their own, a cure for dragon pox was discovered by Gunhilda of Gorsemoor around the end of the 16th century (FW). Wizards and witches have also died (HBP9, Pm) from cases of Dragon Pox! Maybe the Professor is being a bit too dismissive?
Although the date printed on the third Daily Prophet Newsletter (DP3) is 1 June 1999, the timeframe for this event is 1992-1993.
From the Web
Writing by J K Rowling on Pottermore:
Harry Potter Wiki: Dragon Pox