Also known as follicular keratosis, this is a hereditary skin disorder that causes goosebump-like lesions on the back of the arms, thighs or buttocks. The patches of bumps tend to get dry and itchy, particularly during the winter months. Keratosis pilaris occurs at any age. Because it is hereditary, there is no method of prevention. In some cases, it goes away on its own over time; in other cases, the condition is chronic. Keratosis pilaris is not harmful, however, it is very difficult to treat.