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Dermatoses, Erosive or Ulcerative in Cats

With ulcers, the surface layers of the skin are compromised completely, since the defects go deep into the skin. Ulcers require careful wound care to prevent infection, and tend to heal slowly. Erosions are shallow defects in the skin that only affect the skin's upper layers. Erosions can be quite painful, but tend to heal quickly if the skin is protected and the underlying cause is eliminated.

Erosive or ulcerative dermatoses are from a group of dissimilar skin disorders characterized by the presence of erosions or ulcers.

Symptoms and Types

Symptoms will depend on the underlying cause. However, they may include one or more of the following:

• Alopecia
• Erosions or ulcers, which may be found anywhere on the body
• Single or multiple lesions, which may be inflamed (indicated by redness and swelling)
• Lesions over pressure points (where skin lies closest to the bone)
• Dried discharge on the surface of a skin lesion (crust); or, may have moist discharge oozing from the lesion
• Depigmentation in skin and/or hair

Causes

Common causes for skin ulcers and erosions are burns, trauma, and skin infections, as well as more complicated conditions, such as drug reactions, certain types of cancers, and autoimmune diseases of the skin. A wide variety of conditions can result in erosions or ulcers of the skin. Viruses can also be the cause of erosions or ulcers, and can appear identical to burns or trauma.

Your veterinarian may need to run a battery of tests, including blood work, cultures for different types of infections, and skin biopsies to determine the root cause of the reaction and prescribe proper treatment.

In some cases an underlying cause cannot be identified. If that is the case, your veterinarian will diagnose this as an idiopathic disorder or disease.

A partial list of disorders that cause erosions or ulcers of the skin include the following:

Immune-Mediated Disorders

• Inflammation of blood vessels (vasculitis)
• Toxic epidermal necrolysis (tissue death, usually medication-induced)
• Feline indolent ulcer: an inactive, slow healing lip ulcer that causes little to no pain; also called a rodent ulcer, but is not related to rodents. Usually caused by flea bite sensitivity, or food allergies
• Pemphigus (an autoimmune disorder in which the immune system attacks the skin)

Infectious Disorders

• Skin infection caused by Staphylococcus, characterized by the presence of pus (pyoderma)
• Deep fungal or mycotic (parasitic fungi) infections, such as sporotrichosis, cryptococcosis, histoplasmosis
• Superficial fungal infections, like Malassezia dermatitis, and dermatophytosis
• Actinomycetic bacteria, such as Nocardia, Actinomyces, and Streptomyce; indications of an actinomycetic bacterial infection are similar to a fungal infection
• Feline cow pox; transmitted by rodent bite
• Feline immunodeficiency virus (FIV), and feline leukemia virus (FeLV) related conditions

Parasitic Disorders

• Demodectic mange (demodicosis)
• Notoedric mange (affects cats)
• Flea-bite allergy
• Congenital/Hereditary Disorders

Congenital/Hereditary Disorders

• Various skin disorders in which the skin is abnormal at birth (that is, a congenital abnormality), and that may or may not be inherited

Metabolic Disorders

• Excessive production of steroids by the adrenal glands (hyperadrenocorticism), especially when complicated by secondary infections or calcium deposits in the skin (calcinosis cutis)

Cancer

• Squamous cell carcinoma
• Mast cell tumors
• Lymphoma of the skin (mycosis fungoides)

Nutritional Disorder

• Zinc-responsive dermatosis

Miscellaneous

• Thermal, electrical, solar, or chemical burns
• Frostbite
• Chemical irritants
• Venomous snake and insect bites

Diagnosis

Your veterinarian will begin with a full medical history and physical examination. This is especially important owing to the extensive differential list (see Causes). Many of the causes have subtle differences in appearance and distribution.

The wide variance of possible causes, and the similarities of many of the manifestations, make diagnosing and treating a dermatological skin disorder a challenge. An in depth history, which you will provide, will be necessary for the true nature of the disorder to be made apparent.

The history of the itching will be taken into account, as well as incidences of exposure to infectious organisms, and recent travel history (to account for some fungal diseases that can be acquired from environments other than the one in which you and your cat live). Diet, and any other signs of systemic (whole body) reactions will also be recorded.

Lesions, ulcers and blisters will need to be biopsied for an in depth analysis. Your veterinarian will perform a histological skin biopsy -- an analysis of the diseased tissues -- as well as mycobacterial, and/or fungal cultures, and evaluations of fluid and pus from the lesion or blister.

An aspirated sample of the fluids, and a subsequent microscopic examination of the involved cells in the fluid will also be used to determine the presence of bacterial infection, either aerobic or anaerobic (bacteria that can live with, or without oxygen, respectively).

Treatment can be given on an outpatient basis for most skin disorders, but methods of treatment and medications vary. Your veterinarian will tailor a management program that is best for your cat's individual case; if the cause of the dermatosis is known, specific drug therapies may then be prescribed.

One possible method of treatment is hydrotherapy, which can be applied with either a whirlpool bath, or by spraying cool water under pressure against the ulcerated skin. First, make sure that your veterinarian approves of hydrotherapy as an appropriate treatment for your cat's condition.

Avoid the temptation to apply over-the-counter creams and ointments to erosions and ulcers without first checking with your veterinarian, since some commonly used products (such as those containing neomycin) can actually cause a delay in healing.

Other products may contain alcohol or other ingredients that could inflict pain when applied. Keeping eroded, or ulcerated skin clean and protected, with soap that is specially formulated for sensitive skin, will be key to effective and responsive healing

Living and Management

Follow-up care will be on a case-by-case basis, and will depend on the disease process, the presence of generalized (systemic) diseases, medications used to treat the skin and body, and the potential side effects that can be expected from the medications.

Follow-up care with your veterinarian is important, especially for slowly healing ulcers; the progress of the wound should be monitored at least every other week to be sure that healing is proceeding properly, and that infection has not further complicated the healing process.