White cats and squamous cell carcinoma

Squamous cell carcinoma (SCC) is a common tumour affecting the skin of cats.  It affects predominantly poorly haired regions (such as the tip of the ear, the eyelid and the nose).  Affected cats present with what appears to be a non-healing ulcer on the tip of the ear or around the nose.  With time these lesions often progress to black crusty lesions.  This type of tumour is associated with increased exposure to ultraviolet radiation (UVA and UVB) from sunlight.  White cats are at an increased risk of developing SCC (a 13.4 times greater chance was identified in one study).  When cats of other colours present with SCC it typically affects a non-pigmented or poorly haired region.

Dorn CR, Taylor DO, Schneider R (1971) Sunlight exposure and risk of developing cutaneous and oral squamous cell carcinoma in white cats Journal of the National Cancer Institute 46:1073-1078
Ruslander D, Kaser-Hotz B, Sardinas JC, (1997) Cutaneous Squamous Cell Carcinoma in Cats, Compendium of Continuing Education,19:10,1119-1129
Friberg C (2006)  Feline facial dermatoses, Veterinary Clinics of North America Small Animal Practice;36(1):115-40, vi-vii

Epidermolysis bullosa, junctionalis

This condition causes blisters to develop in and around the mouth and on the limbs, leading in the latter case to separation of the nails from the corium (dermis), resulting in inability to stand. The mode of inheritance is unknown but it is believed to be a single gene defect.

Alhaidari, Z., Olivry, T., Spadafora, A., Thomas, RC., Perrin, C., Meneguzzi, G., Ortonne, JP.:Junctional epidermolysis bullosa in two domestic shorthair kittens., Vet Dermatol 16:69-73, 2005.

Ehlers-Danlos syndrome (r)

Ehlers-Danlos syndrome causes affected animals to be born with easily extendible and very fragile skin. Severe lacerations result from the slightest scratch. The mode of inheritance is unknown but it is believed to be a single gene defect.

Sequeira, J.L., Rocha, N.S., Bandarra, E.P., Figueiredo, L.M.A., Eugenio, F.R. (1999): Collagen dysplasia (cutaneous asthenia) in a cat, Veterinary Pathology 36:603-606

Atopy

Atopy is an inherited predisposition develop a hypersensitivity to environmental allergens. Clinical signs include military dermatitis, alopecia and eosinophilic granuloma complex. Diagnosis relies on exclusion of other causes of pruritus. Intradermal testing can be performed to identify the allergen responsible. As food can be one of the allergens, a diet trial should be performed. Treatment involves avoidance of the allergen if possible, immunosuppressive treatment or immunotherapy. A study below describes the condition in 3 related cats and certain breeds of dog are predisposed, suggesting a genetic component.

Foster, A.P. (2002): Diagnosing and treating feline atopy, Veterinary Medicine 97:226
Moriello, K.A. (2001): Feline atopy in three littermates, Veterinary Dermatology 12:177-181

Rex Coat

The hair of affected kittens is wavy and later becomes woolly. In adults it is curly short and often plush. It can result from autosomal dominant or recessive defects. In some lines/breeds the guard hairs and vibrissae (whiskers) may be abnormal or even absent. This defect can be seen in short-haired (e.g. Devon Rex [autosomal recessive trait] and Cornish Rex [autosomal recessive trait]) and long-haired breeds (e.g. LaPerm [autosomal dominant trait]).

Wire hair

This describes an unruly rough coat and is inherited as an autosomal dominant trait.

Alopecia (hairlessness)

This results from having only sparse hairs which are often poorly formed. The hair bulbs are often poorly formed and the hairs are easily dislodged. The skin may be abnormal and thickened. Affected kittens are typically born with a small amount of hair at birth, which is lost by 2 weeks of age, and may re-grow variably later. In some cases it is inherited as an autosomal recessive trait and is part of the breed description of the Sphinx breed.

Saperstein G, Harris S and Leipold HW (1976) Congenital defects in domestic cats. Feline Practice July: 18-43

Basal cell tumour

This is a benign cutaneous neoplasm (cancer). It is reported to be one of the most common cutaneous tumours in cats (ranging from 11-30% of all cutaneous tumours). It presents as a solid or cystic (fluid filled) and sometimes heavily pigmented and/or ulcerated mass, which is often small (95% ≤ 2.5cm). The masses occur with equal frequency in all regions of the body. Complete surgical excision is the treatment of choice. While some authors have suggested that Siamese/Oriental breeds may be predisposed a breed predilection has not been clearly established and reports are conflicting (due to population bias with case selection).  The condition is usually seen in older cats.

Miller MA, Nelosn SL, Turk JR et al (1991) Cutaneous Neoplasia in 340 Cats. Journal of Veterinary Pathology 28: 389-395
Dietsr RW, Walsh KM (1984) Feline Basal Cell tumours: A Review of 124 Cases. Journal of Veterinary Pathology
 21: 51-56

Sweat gland tumour

This type of cancer has malignant and benign forms (adenoma or carcinoma), and may account for ~6% of all feline skin tumours. It usually presents as a solitary tumour, which can either be a firm well-circumscribed mass or a poorly circumscribed diffuse plaque-like lesion.  There is no site of predilection (there is no where on the body that the tumour is more likely to occur). While some authors have suggested that Siamese/Oriental breeds may be predisposed a breed predilection this has not been reported by others.

Miller MA, Nelosn SL, Turk JR et al (1991) Cutaneous Neoplasia in 340 Cats. Journal of Veterinary Pathology 28: 389-395
Kalaher KM, Anderson WI, Scott DW (1990) Neoplasms of the apocrine sweat glands in 44 dogs and 10cars. The Veterinary Record 127:400-403