Hair Loss in Cats: What is Behind it?

It is normal for your cat to lose more hair during the shedding period. However, if the coat becomes very thin or your cat becomes bald, you should do something about it. Unfortunately, the cause of hair loss in cats is often misunderstood.

Reasons for Hair Loss in Cats

The reasons for thin fur (hypotrichosis) or bald patches (alopecia) in cats can be divided into three categories:

Hair growth is disturbed

More hair does not fall out than normal, but hair grows back too slowly. The growth cycle of cat hair can be disrupted by metabolic disorders, for example, or the sparse hair growth is congenital. Overall, however, hair growth disorders are rarer than previously thought. Until a few years ago, it was thought that cats reacted similarly to dogs with hormonal (endocrine) diseases with symmetrical hair loss and called it “feline endocrine alopecia”. However, it is now clear that this is only very rarely the case (e.g. with the rare feline Cushing). In the case of the most common hormonal disease in cats, hyperthyroidism (hyperthyroidism), bald spots are mainly caused by increased cleaning behavior (see 3.).

Nutritional deficiencies or the rare “telogen effluvium” can also disrupt hair growth. In telogen effluvium, many hairs suddenly transition from the growth phase to the resting phase (telogen phase) in response to a severe stress event. About 1-3 months later they all fall out within a short time and the cat gets bald spots. Telogen effluvium does not require treatment because the hair will grow back on its own. Some cats develop telogen effluvium after giving birth to kittens.

The hair roots or hair shafts have been damaged

Such hair damage is usually caused by infections:

• Demodex mites (demodicosis; usually due to a disease that suppresses the immune system, e.g. FIV or FeLV),
• Skin fungi (dermatophytes) or less often
• bacterial hair follicle inflammation (folliculitis)

These causes of hairlessness usually (but not always) also show other symptoms, such as inflamed, open, weeping skin or dandruff. Demodex mites in particular are often difficult to find because they live deep in the skin in the hair follicle.

The cat removes the hair itself

This is the most common reason for hairlessness and thin coats in cats. The technical term for this is feline self-induced alopecia (FSA).

Can’t be with your cat, you think? Experts estimate that 90% of the time, owners don’t realize their cat is licking its bald head because it likes to withdraw. After all, hardly anyone has the time to watch around the clock how often and for how long their cat licks its fur. However, there are some clues that can tell you if your cat has FSA:

Evidence of feline self-induced alopecia

1. Your cat is only bald where it can reach with its own tongue. The bald spots are often distributed symmetrically on the body. Very often, the cat’s belly is bare first.
2. You will find a lot of cat hair in the feces.
3. Your cat regurgitates hairballs (trichobezoars) or you see hairs between her teeth.

Especially with outdoor cats, it is often not possible to find out at home whether the cat is removing its hair itself. In the veterinary practice, this is usually very easy, with a so-called Trichogramma:

Plucked hairs from the affected region show damage caused by the cat’s tongue and teeth under the microscope. They are broken off or frayed and are actually still in the growth phase (anagen phase), which can be recognized by the hair root.

Is your cat licking his head because he is stressed or scared?

Without knowing your cat, one can say: Most likely not. Studies (e.g. Waisglass 2006) have shown that feline psychogenic alopecia is often misdiagnosed. Only one in ten cats that lick themselves bald does so because of a mental illness.

Finding the physical causes of excessive brushing can sometimes be difficult and time-consuming, but it’s worth it because they’re usually treatable. The final diagnosis of psychogenic alopecia should then also be made by a veterinarian who specializes in behavioral problems (can be found e.g. at www.gtvmt.de) after all other medical causes have been ruled out.

However, if there have been any major changes in your cat’s environment that could make her stressed, you should definitely tell your veterinarian. E.g.:

• Relocation or other changes in their territory
• The arrival of a new family member (human, cat, or another animal)
• loss of a family member
• major changes in daily routine

The more precisely the cause of stress is identified, the more effective behavioral therapy can be. The therapy can be supported (depending on the severity of the problems) with medication, pheromones (e.g. Feliway), and/or supplementary food with L-theanine for stressed cats. A recent study (Dramard 2018) was able to confirm an improvement in anxiety-related behavioral problems (excessive cleaning, urine marking, panic attacks, etc.) with a feed additive containing L-theanine.