I am glad to hear the the scabs are gone. We had a GSD in Italy who had similar symptoms and it turned out to be Leishmaniasis. It was pretty scary stuff. Vet info says that the most common causes are:
Parasites, both internal and external—mites, fleas, chiggers, gnats, flies, lice, intestinal worms and any of their larvae
Allergies caused by ingestion or direct contact
Constant irritation resulting in chewing on or licking of irritated site
Excessive bathing resulting in the depletion of natural skin oils and therefore the drying out of the skin
Poor nutrition and/or mineral deficiency
Environmental factors including exposure to chemicals used in pesticides, cleaning or other household products
It is best to avoid any irritants whenever possible rather than having to treat the cause. Treatment takes time and money and makes life miserable for the dog for a period of time during treatment.
Parasites in Causing Dog Skin Scabs
Bites incurred by parasites, such as fleas, mites or other biting insects and their larvae can cause irritation at the bite site resulting in a dog scratching, biting or licking the bite site. If the bite site bleeds then a scab can form. This scab can also become itchy and result in more biting, scratching and licking and therefore continuing a vicious cycle.
Biting the site can result in a large area becoming involved and a larger scab. Sometimes medication is necessary to alleviate the itch and/or a bandage of some sort is applied to prevent further scratching, biting and licking in order to break the cycle.
Allergies and Canine Skin Scabs
Allergies can be caused by direct contact with an irritant, such as pesticides or other household products, or by the ingestion of a product that causes an allergic reaction. Some breeds of dogs are allergic to certain foods or are unable to digest them. This can cause an outbreak of a rash, which when irritated by scratching, biting or licking can result in a formation of a scab. Elimination of the irritant and treatment of the resulting scab is the only way to combat allergies.
Bathing to Prevent Skin problems in Dogs
Every owner wants a dog that is clean and well groomed; however, excessive bathing can dry out the natural oils in the skin, causing itching. Shampoos can also cause itching. Whenever a dog irritates the skin by scratching, biting or licking, he can cause a scab to form over the irritated site. Use of shampoos that do not rob the skin of its natural oils is important for the prevention of this type of irritation.
Sometimes lack of certain minerals and vitamins in the diet can result in the formation of scabs. The skin needs certain nutrients to maintain its gloss, fur and natural defenses against parasites and the elements. Any imbalance can cause scabs to form on the skin.
Prevention of scabs can be as easy as providing proper nutrition, the elimination of any environmental irritants, proper bathing and the avoidance of parasite infestation.
Follow the link below to read more articles about scabs in dogs
Read more: Causes of Dog Skin Scabs - VetInfo