Grey Skin Moles Gelding Has Weird Wart-like Bumps In Clusters On The Leg???

Gelding has weird wart-like bumps in clusters on the leg??? - grey skin moles

The spots on my 23-year-old gelding ... What are they?
My horse is 23 years. In each of the legs is formed from an area the size of a half dollar, and the layers of dry skin, like moles gray and dry. It is in a pasture, use one of our horse ranch and fed grass and alfalfa hay at a time ... Have you any idea what could be?
Oh ... and .... No one is about an inch from the mother chestnuts, and others are Väring places, but only on the legs

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6 minutes ago
I have 8 years does not take a bath with shampoo as good as ever, only when necessary ... Use mane and tail ... He is a bay gelding. There is another mother ... I'm pretty sure it's not ringworm ... aroung 100 horses were geldings, and none of us (or other mares and stallions for that matter) has spots .... How do you feel does not sound so painful to the touch, if we react / feel, really!