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Dermatoses, Erosive or Ulcerative in Dogs

Erosions are shallow defects in the skin that only affect the skin's upper layers. They can be quite painful, but tend to heal quickly if the skin is protected and the underlying cause is eliminated. With ulcers, the surface layers of the skin are compromised completely, since the defects go deeper into the skin. Ulcers require careful wound care to prevent infection, and tend to heal slowly. Erosive, or ulcerative, dermatoses (diseases of the skin) are from a group of dissimilar skin disorders characterized by the presence of erosions or ulcers.

The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the PetMD health library.

Symptoms and Types

The symptoms will depend on the cause. However, they can include one or more of the following:

• Erosions or ulcers; they may be found anywhere on the body
• Hair loss (alopecia)
• Single or multiple lesions; lesions 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
• Loss of pigment in skin and/or hair (depigmentation)

Causes

A wide variety of conditions can result in erosions or ulcers of the skin. Common causes 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. 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 (sample of skin tissue) to determine the root cause of the reaction and prescribe proper treatment.

In some cases an underlying cause cannot be identified. Your veterinarian will diagnose this outcome as an idiopathic (unknown) 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)
• Canine juvenile cellulitis: also referred to as 'puppy strangles,' this condition is characterized by swelling of the head, neck, muzzle, eyes, and ears. The skin will crack in response to swelling, with the swollen lymph nodes draining through the skin and leaving crusted lesions
• 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

Parasitic Disorders

• Demodectic mange (demodicosis)
• Sarcoptic mange
• Flea-bite allergy

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
• Generic dog-food dermatosis (allergy to specific ingredients in dog food)

Miscellaneous

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

Diagnosis

Your veterinarian will begin with your dog's full medical history and a 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 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 pet live). Diet, and any other signs of systemic (whole body) reactions will be recorded.

Lesions, ulcers and blisters will need to be biopsied for an in depth analyzation. Your veterinarian will perform a histological skin biopsy -- an analyzation 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).