Scrotum is purplish, i have a dull ache which has remained there for a year. what can this discoloration mean?

Exam: It means you should see your doctor. He or she will be able to tell you if you have an infection, a skin rash or some unusual blood vessel problem of the scrotum. In spite of all this, the purple discoloration you describe is probably nothing serious whatsoever.

Possible a hydrocele: Scrotum would be swollen ; skin somewhat stretched with lossof rugations (wrinkles). Suggest you consult a urologist who might well recommend a scrotal ultrasound.