Alopecia (hairlessness) in dogs

There are many different reasons why a dog loses its fur. Hairs in a coat must sooner or later be shed. But sometimes more hair sheds than grows back.

There are a variety of underlying causes. Some of the most common causes are demodex, alopecia x, ringworm, autoimmune disease, bacterial infection, hormonal causes or damaged skin.

Common causes of hairlessness in dogs

• Hair follicles remain in the resting phase and does not transition into the growth phase.
• Itching can cause your dog to lick and bite itself, resulting in hair loss. 
• Wounds or inflammation can cause the destruction of hair follicles.

Dog hair growth

The dog's hair growth goes through three different phases:

• Growth phase
• Transition phase
• Resting phase

The growth phase

During the growth phase, the hair grows and the length of the hair is determined by the dog's breed. Dogs with long fur have a longer growth phase. The length of the phase varies depending on the dog breed.

The transition phase

The transitional phase lasts only a few days until the hair follicle becomes inactive and thus enters the resting phase.

The resting phase

During the resting phase, hair falls out of the hair follicles, leading to loss of fur. Some dog breeds shed more fur than others, this is because their resting phase is shorter. When the resting phase is over, the hair follicle starts over with the growth phase.

Different types of alopecia

Alopecia can be grouped in different ways; congenital, hereditary or acquired cause. Acquired cause can be inflammatory or non-inflammatory.

Based on localisation, alopecia can be grouped as follows:

• Local alopecia - in local alopecia, a spot is seen that is hairless. Possible cause could be demodex or ringworm.
• Multifocal alopecia - in multifocal alopecia, multiple spots and a greater spread are seen. Possible cause could be demodex, bacterial infection or ringworm.
• Symmetrical or diffuse alopecia - possible cause can be hormonal, congenital, hereditary, demodex or bacterial infection.

How an alopecia diagnosis is made

On an affected dog, a vet may examine several hairs. Tissue samples (biopsies) from the skin may be taken to, among other things, assess spread. Other ways to diagnose the underlying cause are through scraping, cytology, blood tests and hormone tests.

Treatment of a dog with alopecia

There is no cure for alopecia, but if the root cause of your dog's hair loss is treatable, treatment can have a positive effect and the fur can return.

Regular fur care

It is not possible to prevent hairlessness, but it is always good to get into the habit of going through the dog's fur and brushing or combing it regularly. This makes it is easier to detect any changes in the coat or in the skin as early as possible.