Why Is My Dog Losing Patches of Hair?

Updated February 21, 2017

Dogs lose their hair for all sorts of reasons. Canine alopecia---the medical term for this condition---is normal for some dogs as hair naturally falls out to allow for new hair. For others, hair loss is a symptom of a possibly serious illness. Tests performed by your veterinarian are the best way to identify the cause of your dog's hair loss.

Possible Hair Loss Illnesses

A whole host of illnesses cause dogs to lose patches of hair. Some of them relate to specific diseases, such as testicular cancer, mange and hypothyroidism, which affect all dogs regardless of breed. Other explanations of hair loss may be due to a breed-specific condition, like vitiligo---a condition affecting rottweilers and Belgian Tervuivens or sebaceous adenitis, which impacts poodles. Stress also causes a dog to lose patches of hair. Dogs suffer from pattern baldness as well.


Depending on the cause, hair loss may be localised or generalised. Hair may fall out in clumps or patches. The dog's coat may appear dull and fragile. Hair loss may be accompanied by other symptoms, including skin depigmentation, lethargy and poor appetite.


A veterinarian needs to perform a complete exam to determine the cause of hair loss. Pet Education states the exam may involve a series of diagnostic tests to conclude whether or not hair loss is attributed to an underlying condition or to rule out possible illnesses that affect a dog's hair.


Drug therapy to cure or reduce the chance of hair loss is the most common treatment for most hair-related illnesses. When a more serious underlying disease is detected, surgery may be required, in addition to drug therapy.


In some cases, the cause of canine hair loss is undetermined. When this occurs, poor nutrition may be to blame and a diet change is usually recommended. The Dog Health Guide reports that 90 per cent of a dog's hair consists of protein and as much as 30 per cent of protein needed for hair and skin comes from its diet. A diet without enough protein makes a dog's hair brittle and liable to fall out. Increasing the dog's protein intake and adding a diet supplement, like fish oil, helps restore the hair's strength and lustre.

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About the Author

Christie Gross has been writing since 1998. Her work writing public policy platforms for elected officials nationwide has been featured in national and local newspapers under various client pen names. Gross has a Bachelor of Arts in English and political science, as well as a Master of Public Administration from the University of Delaware.