Symmetrical Hair Loss on a Dog's Chest

Symmetrical hair loss on a dog's chest can prove to be unsightly and uncomfortable for the animal. Skin conditions in dogs are relatively common and can cause concern for pet owners. Many of the conditions are symptoms of other, underlying conditions; treating these underlying conditions can alleviate much of the skin issues and make for a happier, healthier dog. Several causes for hair loss have been identified, some more common than others.

  1. Hormones

    • Hormonal changes are one of the most common causes of symmetrical hair loss in dogs and the loss often occurs over the neck and chest areas. Hypothyroidism, in which the thyroid fails to function properly, is the most common hormone deficiency resulting in skin and hair conditions. Other hormone-related conditions that result in symmetric hair loss are hypoestrogenism/hyperestrogenism, commonly seen in young, recently spayed females, and growth hormone-responsive alopecia which is thought to be caused by an enzyme deficiency and is most commonly seen in the 'spitz'-type dogs, such as Chow Chows and Pomeranians. It is also seen in poodles.

    Cushing's Disease (Hyperadrenocorticism)

    • In Cushing's disease, the dog's body reacts to the presence of corticosteroids. These steroids may be present due to tumors in the body manufacturing the chemicals or may be present due to medications for other disorders. If tumors are responsible, surgery will be done to remove the tumors and if it's medication-induced, the corticosteroids will be eliminated. Cushing's can cause symmetric loss of hair over the animal's trunk and chest.

    Obsessive Behaviors

    • Dogs may develop obsessive behaviors due to stress or breed predisposition. These behaviors most likely will involve licking. Large patches of hair loss are common on the belly, back, tail and lower chest and may be symmetrical in appearance. These areas must be treated or they can grow infected and the root causes of the obsessive behaviors, such as stress, need to be reduced to prevent flareups.

    Ringworm

    • Fungal infections resulting in round, symmetrical patterns of hair loss over a dog's body -- most commonly the neck, back and chest regions -- are referred to as ringworm. No actual worms or other parasites cause this condition. Ringworm is treated with topical or oral anti-yeast medications. The patches may be scaly or seeping. Ringworm can transfer to humans, especially children or those with compromised immune systems.