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Dermatoses, Depigmenting Disorders

Skin dermatoses is a medical term that can be applied to any number of bacterial infections of the skin or genetic diseases of the skin. Some dermatoses are cosmetic conditions involving loss of pigmentation of the skin and/or hair coat, but are otherwise not harmful.

Symptoms and Types

• White hair (known as leukotrichia)
• Partial or total lack of pigment in the skin (known as leukoderma)
• Reddening of the skin (known as erythema)
• Loss of the top surface of the skin (known as an erosion or ulceration, based on depth of tissue loss)
• Siamese cats may be disposed to a condition characterized by symmetrical lack of pigment in the skin and a white hair coat, especially involving the face and nose

Causes

• Bacterial skin infections; the most commonly affected areas are:
  • Lips
  • Eyelids
  • Nostrils
• Fungal infection of skin
• Contact hypersensitivity (allergies)
• Skin on face tends to be primarily affected
• Red skin and pus - face and ears
• Crusting scabs and pus on skin
• Loss of skin/hair color after skin was inflamed
• Loss of color on nose and lips, vision loss
• Seasonal nasal depigmentation
• Inflammation of the arteries of the nasal philtrum (very front of nose, above upper lip)
• Albinism (genetic)
• Vitiligo (smooth white patches of skin due to loss of skin color)
• Severe: skin and bodily organs affected
• Autoimmune disease (often there is a genetic predisposition)
• Systemic lupus erythematosus
• Discoid lupus erythematosus
• Pemphigus foliaceus
• Pemphigus erythematosus
• Uveodermatologic syndrome
• Hormonal disorders
• Drug reaction

Diagnosis

Your veterinarian will perform a thorough physical exam on your cat, taking into account the background history of symptoms and possible incidents that might have precipitated this condition, such as whether your cat suffered a recent infection. You will need to give a thorough history of your cat's health and onset of symptoms. Your veterinarian will order a blood chemical profile, a complete blood count, an electrolyte panel and a urinalysis. Blood samples can be tested for autoimmune factors.

As part of your cat’s physical exam, your veterinarian will take skin samples and skin scrapings to send to a lab for bacterial and fungal cultures. If the skin biopsy shows that skin cells are separating from each other (acantholytic), this is diagnostic for pemphigus. Direct immunofluorescence of skin samples using fluorescent dyes can also be used to demonstrate antibodies. Your veterinarian may also take fluid samples from your cat’s joints to check for lupus.