A picture would certainly help but it sounds a lot like scab. Scab on the fruit itself is usually just limited to skin blemishes, with no effect on the meat of the fruit. But it also damages the foliage and cause premature leaf drop. Repeated years of this can weaken the tree, making it much less productive and could even cause its death. Take samples of both the fruit and any damaged or fallen foliage into your local extension office for a diagnosis and treatment options.

Sounds like fly speck or sooty blotch. Harmless, cosmetic, may affect storage life.http://www.caf.wvu.edu/kearneysville/disease_descriptions/omsooty.html