Please be aware that itching is not usual in outbreaks of this problem, it may occur if secondary infection has set in. Should the dogs immunity to the mite drop the signs are usually, loss of hair on the face and front legs with scaling and reddening of the skin, it can however spread to other areas of the body, even the whole body. It is potentially a serious disease and should be treated by a vet although efforts to improve the dogs immunity with good feeding practices can do nothing but good. Animals who have once been effected may have recurring attacks and should not be used for breeding not only because there is a danger that they may past the tendency of poor immunity to their offspring but in the case of the bitch the act of whelping may trigger an attack.

Yep, spot on!
Dawn.