Welsh corgis are known for being healthy, sturdy and fit. While the breed suffers from relatively few genetic health problems, it is prone to skin allergies that can cause hair loss. They are also susceptible to all the standard causes of hair loss in dogs, including diseases, infections and parasites.
As a double-coated breed corgis shed their entire undercoat twice a year, usually in spring and fall. The amount of hair lost during this shedding cycle can be massive. The hair often comes out in tufts, making it appear the dog is suddenly losing patches of hair. When this hair sheds out, however, a thinner coat should already be in place. Corgis also shed smaller amounts year-round, and the coat will change in density depending on the weather. Hair loss from shedding is normal, but balding from shedding is not. There is no treatment to stop shedding, which is a natural part of the corgi's hair growth cycle. Regular grooming during most of the year and use of a de-shedding brush during times of heavy shedding will help keep the coat looking nice and reduce the amount of hair left around the home.
Corgis are more prone to allergic skin reactions than many other breeds. Pollen, grass, shampoos, chemicals, foods and even certain fabrics or carpets can trigger an allergic reaction. Hair loss due to allergies is usually caused by the dog picking at places that itch. This may include scratching, biting, chewing or licking a single spot until it becomes bald. The hair is being removed by the constant friction and not falling out on its own. Treatment for allergies in corgis includes avoiding the allergen and administering antihistamines, steroids and skin-soothing baths and salves. Once the allergies are under control, the hair should regrow.
Many diseases can cause a corgi to lose hair, including several autoimmune disorders. While corgis are generally healthy and not as susceptible to these diseases as many other breeds, they can still be affected. Conditions that cause hair loss include hypothyroidism, Cushing's syndrome, Addison's disease, certain types of cancer and hormonal imbalances. Identifying and treating the underlying disease will restore hair growth in most (though not all) cases. Corgis will typically exhibit additional symptoms if they are affected by disease and the hair falls out on its own, not due to scratching or licking.
Infections and Parasites
Bacterial and fungal skin infections can cause a corgi to lose hair. This hair loss is usually characterized by red, flaky, oozing or inflamed skin, and occurs in patches rather than in a single location. Parasites such as fleas and mites can also cause hair loss. Corgis with infected skin or parasites may lick and scratch at the site, making it difficult to differentiate from an allergy. A veterinarian can perform a simple skin test to determine whether an infection or a parasite is present. Infections are usually treated with antibacterial or antifungal creams, and occasionally antibiotics. Special dips, sprays and baths are used to kill fleas and mites. Hair usually regrows after an infection or infestation has been treated.
Poor nutrition in any dog, including a corgi, can result in hair loss. If a corgi is malnourished or receiving an imbalance of vitamins or fat, he could begin to lose hair. In addition to falling out, the hair will usually appear dull, dry, coarse and unhealthy. A high-quality dog food with a proper balance of protein, vitamins and minerals should help restore the coat.