Hair loss that is associated with itchy skin can imply numerous causes. Allergies are one of the most common causes and are typically broken down into three categories. Dogs can be allergic to flea bites and tend to lose the hair over their lower back and hips when they have an allergic flare-up. Dogs with environmental allergies such as pollen, grass, weeds, trees, and dust mites usually lose hair on their limbs and their bellies. Dogs with food allergies can be more difficult to differentiate because they lose hair almost everywhere!
Itchy dogs tend to scratch or chew on themselves, and this can bring about secondary bacterial infections that result in further hair loss. Fungal infections are also possible due to the presence of small amounts of yeast on healthy skin. When skin becomes dry and inflamed, there is an increased risk for bacterial infections, and when there is excess moisture from licking, yeast can cause infections, too. Skin mites can also cause hair loss, although sometimes mites likeDemodex may not cause itchiness, so it is important to have your dog tested when you see hair loss.
Another type of fungal infection, ringworm, is caused by a fungus that is transmissible by contact. It can come from other animals or can come from dirt and soil. This fungus can cause ring-like lesions on the skin which results in a round-shaped area of hair loss. Ringworm is zoonotic which means that humans can also develop it from contact, so it is important to make sure to address itchy skin with your veterinarian (and sometimes with your own physician) right away!
Hormonal imbalances, aka endocrinopathies, can also cause hair loss. Hypothyroidism is when a dog’s thyroid gland does not produce sufficient amounts of thyroid hormone. As a result, dogs can become overweight and will drink and urinate a lot more than normal. Their hair coats become brittle and they can lose hair more easily, making them more susceptible to skin infections and itching. Another disorder known as Cushing’s disease is when a dog’s adrenal glands produce too much cortisol. This ends up causing many problems such as a potbelly, darkened skin, itching and hair loss, and excessive appetite, thirst, and urination. It affects middle-aged to senior dogs, and treatment depends on the type of Cushing’s disease present. It can be easy to attribute hair loss to allergies alone, but if your dog is drinking or urinating a lot, he may need testing for some of these illnesses.
Not all causes of hair loss require treatment. Pressure sores, which are skin-level ulcers, are a lot like calluses and develop in locations that contact hard surfaces consistently. The elbow is one of the most common places. Pressure sores become a health concern when they become dry, cracked, and start to bleed. If your dog starts to develop them, consider new bedding to help prevent them from worsening.