Hair loss (alopecia) in dogs can be a worrying problem. Alopecia has many varied causes and always warrants investigation by your vet.

Hair loss can be the result of skin infections such as Ringworm (not a worm but a fungal infection) or bacterial infection, parasites such as mites, and is often the result of the dog scratching or licking an itchy area due to a flea infestation or skin allergy for example. Older dogs can also lose hair due to hormonal problems such as an underactive thyroid gland or adrenal gland problem. Overgrooming due to a behavioural problem is a lot less common in dogs than in cats. Some causes of hair loss are transmissible to humans, although this is unusual, so this is definitely a time not to delay that visit to the vets!

General poor health, nutrition or underlying disease can also make the coat lose shine and possibly also result in hair loss.

Investigation

Your vet will need to look for the cause of the alopecia. As fleas are a common cause of itch and resulting hair loss, he/she may recommend a flea treatment (which is advisable to keep up to date anyway). Your vet may also take samples of hair or scrape a little sample of skin (this is painless) to test for Ringworm and parasites, or take blood samples to look for underlying diseases such as hormonal problems. Occasionally a small skin sample will be taken under an anaesthetic or an allergy skin test performed. Consultation with a veterinary dermatologist is recommended if the cause for the alopecia is unclear.

Treatment

The treatment for alopecia obviously depends on the underlying cause. It is important to pursue investigations to ensure correct treatment. Flea control is always recommended for all dogs and your vet may recommend other treatments if another cause is identified (e.g. anti-fungal treatment for Ringworm). Treatment of allergic skin disease can be challenging and taking advice from a veterinary dermatologist is advised.

Hormonal conditions such as an under-active thyroid or adrenal gland problem may require long-term treatment with medications.

If you notice your dog losing hair then consult your vet and it is always a good idea to ensure flea treatment is up to date.