From lush to patchy

You’ve always been drawn to dog breeds with lush, soft coats. You’ve wanted a Golden Retriever all your life, and just about a year ago, an adorable ball of fluff finally wormed its way into your heart. You’ve enjoyed many fluffy days so far and hope for many more to come. However, this morning, while happily running your fingers through your dog’s thick fur, you suddenly came across a hairless patch. Wait, no—it is two hairless patches! How on earth didn’t you notice them before?!

Finding bald spots on your otherwise perfectly fluffy companion can be alarming. Loss of hair—clinically known as alopecia—is a very common symptom in animals with fur, and it can occur for a variety of different reasons ranging from simple bug bites to complex internal imbalances.

1. Pesky Parasites (Internal and External)

Alopecia can frequently be traced back to parasites. This is why staying strictly on top of your dog’s preventative anti-parasitic treatment schedule is so incredibly important.

• External Parasites: Fleas and ticks are the usual suspects. When they bite, they introduce specific allergens present in their saliva into your dog’s skin. This causes severe inflammation, intense itching, and the eventual loss of hair in that localized area as your dog scratches relentlessly. Mite infestations—such as mange or scabies, which inhabit the hair follicles or skin surface—also cause severe, crusty hair loss. These can be treated with topical spot-ons, sprays, or oral preventative tablets.

• Internal Parasites: It might surprise you, but internal hitchhikers like Giardia, hookworms, whipworms, roundworms, and tapeworms can also cause hair loss. They hijack the dog’s digestive system to the point where the dog becomes severely malnourished. As the body lacks the vital nutrients needed to sustain a healthy coat, the hair begins to thin or fall out. Regular deworming pills keep these infections at bay.

2. Endocrine and Hormonal Imbalances

Endocrine diseases involve the hormone production and balance within your dog’s body. When alopecia is tied to the endocrine system, it is usually indicative of a more serious underlying health problem. A key visual clue? Hormonal hair loss typically presents as patchy, symmetrical baldness on both sides of the animal’s body, often without the severe redness or itching seen with parasites.

• Estrogen Issues: Increased estrogen can affect hair growth, usually indicating problems with the adrenal glands, ovaries, or testicles. It can also be caused by an overdose of estrogen during hormone replacement therapy (sometimes used for incontinent female dogs), or by conditions like polycystic ovaries.

• Testosterone Imbalance: In male dogs, both unusually high and low testosterone levels can lead to alopecia. Androgen imbalances might result from testicular tumors (which elevate hormone levels) or from standard castration (which reduces them).

• Adrenal Gland Diseases: Two classic hormonal disorders affecting the adrenal gland that frequently result in hair loss are Cushing’s disease (caused by increased cortisol levels) and Addison’s disease (caused by dangerously low mineralocorticoid and glucocorticoid levels).

3. Bacterial and Fungal Infections

Hair loss caused by bacteria or fungi usually appears in random shapes, sizes, and locations around the body. Ringworm, for example, is a notorious fungus that creates highly distinctive, circular bald patches with crusty or red edges.

Important Safety Note: You must take special precautions when dealing with suspected fungal infections. Some of these organisms, including ringworm, are zoonotic, meaning they are highly contagious and can easily infect humans, too!

• Systemic Treatment: If the infection has spread and established itself in multiple locations across the body, your veterinarian will likely prescribe systemic treatment. It is much easier and more effective to treat widespread infections through oral medications (like antibiotic or antifungal tablets) or subcutaneous injections.

• Topical Treatment: If the infection is localized to just one or two small spots, topical treatments like antiseptic or antibiotic/antifungal creams are usually sufficient. If you use a cream, you must prevent your dog from licking the ointment off before it absorbs. Unless the packaging explicitly states it is safe for ingestion, popping an Elizabethan collar (the “cone of shame”) on your dog is the safest way to ensure the medicine actually does its job!