Feline paraneoplastic alopecia

• Rare and unique to the cat (Miller et al., 2013). Can be considered a cutaneous marker for an underlying malignancy (Hnilica, 2011).
• Associated in most cases with a pancreatic malignant tumour, either acinar or pancreatic duct. In these cases metastasis has often occurred at the time of diagnosis. Bile duct carcinoma has also been described, and most recently a single case was reported of a metastasising intestinal carcinoma (Grandt et al., 2015).
• Occurs often in cats older than 10 years.
• No sex or breed predilection.

Clinical signs

• Rapid in onset (weeks to a few months).
• Alopecia begins ventrally and then spreads to the limbs, sparing the head in most cases.
• Focal areas of erythema with a characteristic shiny and glistening skin.
• There may be crusting and waxy debris associated with secondary Malassezia, leading to pruritus.
• Loss in weight and general signs of illness associated with the underlying malignant tumour.

Differential diagnosis

(Hnilica, 2011)

• Hyperadrenocorticism.
• Fleabite hypersensitivity.
• Dermatophytosis.
• Food allergy.
• Cutaneous drug eruption.
• Telogen de uxion.
• Alopecia areata.

Diagnosis

• History, physical examination. The distinctive appearance of the signs in an older cat, which are sudden in onset and with easy epilation of the skin, are all highly suggestive.
• Rule-out of differentials.
• Skin biopsy. Acanthosis, parakeratosis, follicular atrophy and lack of trichilemmal keratin (Miller et al., 2013).
• Radiography and ultrasonography may enable a diagnosis, but not always as masses may be too small to visualise.
• Exploratory laparotomy.

Treatment

• Appropriate treatment of secondary pyoderma and Malassezia dermatitis to control pruritus.
• Supportive care.
• Complete removal of an underlying malignant tumour would be the theoretical treatment of choice. Curative surgery has not been reported although there was a temporary improvement in one cat before return of clinical signs with tumour recurrence (Tasker et al., 1999).

Prognosis

• The prognosis is very poor as many underlying tumours have metastasised by the time the diagnosis is made.
• Most cases die within eight weeks of diagnosis with euthanasia frequently necessary.
• Illustrations by courtesy of David Lloyd, Royal Veterinary College Dermatology Group.

References and
further reading

• Grandt, L-M, Shroeder, S., Kochlerk, K. and others (2015) Feline paraneoplastic alopecia associated with metastasizing intestinal carcinoma. Journal of Feline Medicine and Surgery 1 (2).
• Hnilica, K. A. In: Small Animal Dermatology – A Color Atlas and Therapeutic Guide, 3rd edition, pp304-309. Elsevier, 2011.
• Miller, W. H., Grif n, C. G., Campbell, K. A. In: Muller and Kirk’s Small Animal Dermatology, 7th edition, pp568-569. Elsevier, 2013.
• Tasker, S., Griffon, D. J., Nuttall, T. J. and others (1999) Resolution of paraneoplastic alopecia following surgical removal of a pancreatic carcinoma in a cat. Journal of Small Animal Practice 40 (1): 16-19.