No. They're actually called keratosis pilaris - the cause is unknown, but some claim that it's a hereditary condition.
You can soften and help slough off bumps by rubbing them with a mixture of equal parts petroleum jelly and either water or cold cream. If that doesn't work, prescription Retin-A probably will, but it can irritate the surrounding skin. A better alternative: prescription LactiCare-HC Lotion 2 1/2%, which contains lactic acid to dissolve dead skin cells and hydrocortisone to soothe any acid-induced irritation. Rub lotion onto bumps twice a day until they clear up.