What is alopecia?
Alopecia simply means a lack of hair where hair is normally present. Hair loss in dogs can be congenital, meaning the dog was born with it, or it can be acquired. A dog born with alopecia may or may not have gained it through hereditary means and it may be apparent at birth, or shortly thereafter. Alternatively, the dog may be born with a normal coat, and hair loss occurs as they mature into a young adult. With acquired hair loss, the dog in question was born with a normal coat and had normal hair follicles at one time that could produce structurally sound hairs, and this is no longer the case.
Causes of hair loss
The first contender for why your dog may be going bald is allergies. This may be due to environmental causes, such as pollen or molds, or parasitic causes, such as mites or fleas. Watch for the itchiness that causes this type of hair loss along with excessive biting and scratching. Parasite infestations may also cause mange.
Another problem to watch for in case of hair loss is ringworm. Ringworm is accompanied by crusty areas, scaliness, bumps on the skin containing fluid or pus, bumps on the skin containing air, itchiness and draining.
Cushing's disease could be another cause of hair loss. Though it typically occurs in older dogs, younger dogs who overuse corticosteroid drugs may be affected as well. Along with the hair loss, symptoms include darkening of the skin and the development of a pot belly.
The next possible culprit may be pressure sores. More common in older, larger dogs, pressure sores develop when a bony pressure point, such as an elbow, comes into constant contact with hard surfaces. This causes the skin to become callous and lose hair.
If the dog is typically densely coated and has recently undergone clipping in preparation for surgery, post-clipping alopecia may be the cause of the persistent bald spot. The only thing to do in this case is to be patient while the coat grows back.
Hypothyroidism may also be a cause of hair loss. This occurs when the thyroid gland stops working the way it should and causes the dog's hormones to be unbalanced. Other symptoms of hypothyroidism include lethargy, obesity, dry or brittle hair and changes in skin color.
Reaction to a foreign body might also cause bald spots. This means thorns, glass, or even their own hair was lodged in the dog's skin and caused inflammation.
The final cause of hair loss may be simple genetics. Some dog breeds are more likely to develop bald spots than others in the chest, outer ear, thighs, back, or lower neck areas. Be sure to rule out all other possibilities before deciding your dog is simply genetically prone to hair loss.
When to see a vet
Always be sure to go see a veterinarian if the dog's hair loss is accompanied by bad odor, itching, infected or irritated skin, or behavior changes.