Veterinarian Column: Hair loss caused by disease

by Alice's Dog & Cat獣医師

Autumn is the season for shedding. Hair shedding is seasonal hair loss and is a physiological phenomenon. This time, we will explain in detail about hair loss and hair loss caused by diseases.

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Causes of alopecia

Alopecia caused by inflammation




non-inflammatory alopecia



・Various types of alopecia

traumatic alopecia

Traumatic alopecia is caused by biting, rubbing, or the cat's licking and breaking the hair.


・Dermatitis caused by fleas or scabies

Psychogenic hair loss: Psychogenic hair loss in cats is caused by chronic excessive grooming due to stress.

We will deworm and treat the causes of allergies, fleas, and scabies.

In cases of psychogenic causes, treatments include eliminating the stress that causes it, using an Elizabethan collar to prevent the affected area from being licked, and drug therapy.

infectious alopecia


・Demodex mites


A skin test will be performed to check for infection. Infections are treated with topical and oral medications.

Immune-mediated alopecia

・Sebaceous adenitis

・Superficial pemphigus

・Alopecia areata

・Erythema multiforme

・Lupus erythematosus

・Epitheliotropic lymphoma

Diagnosis is performed by performing a skin biopsy. Treatment uses steroids and immunosuppressants.

hormonal hair loss

Removes hair symmetrically . Skin pigmentation can be seen.

・Hyperadrenocorticism (Cushing's syndrome)


・Sex hormone imbalance: Rarely seen in middle to elderly unneutered or unneutered dogs.

・Alopecia X : The most common dog breed is Pomeranian.

Hormonal hair loss has symptoms other than hair loss. If the cause is the adrenal gland or thyroid, the underlying disease will be treated. If the cause is sex hormone imbalance, this can be corrected by spaying or neutering.

ischemic alopecia

・Alopecia after rabies vaccination (local, systemic)

There is often no treatment.

various alopecias

・Pattern hair loss: The most common dog breeds are miniature dachshunds and miniature pinschers . Symmetrical hair loss occurs on the auricles and thighs .

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- Telogen effluvium: Sudden generalized hair loss occurs after a serious illness such as high fever.

- Hair loss after shearing: This occurs when hair does not regrow due to frequent shearing.

- Palecoat alopecia: This is a genetic disease that causes light-colored coat hair loss in dogs with blue or fawn coats .

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・Black coat dysplasia: Dogs with coats of two or more colors lose their black coats .

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・Seasonal flank alopecia: Hair loss occurs from November to March and resolves naturally from spring to summer. Common dog breeds are boxers and English bulldogs .

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There is no established treatment for these alopecias; melatonin may be administered, or no treatment may be given and the condition may be observed.

Compared to alopecia that is accompanied by inflammation, alopecia that is not accompanied by inflammation is less likely to be recognized as a disease. Diagnosis may take time as various diseases are ruled out.

Hair loss, which is just a skin symptom, can also be a systemic disease, such as hormonal alopecia. In the case of hormonal hair loss, the underlying disease must be treated as various complications can occur. Be sure to groom your pet regularly to prevent skin diseases and to notice changes in their skin and coat.