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Ulcerativea and Erosive Skin Disorders
BASIC INFORMATION 
EPIDEMIOLOGY
SPECIES, AGE, SEX: Vary according to the underlying pathologic process:
• Some dermatoses are seen more frequently or strictly in one species rather than another (e.g., eosinophilic granuloma in cats).
• Young animals are predisposed to genetic defects or infectious diseases, whereas older animals are predisposed to immune-mediated diseases or neoplasia.
CLINICAL PRESENTATION
• Travel history (e.g., leishmaniasis in dogs traveling to Europe), grooming and boarding (contagion risk; e.g., herpesvirus infection in cats), and similar environmental information may affect a patient’s risk of developing a certain condition.
• Presence of signs of systemic illness (e.g., lethargy, anorexia, lameness, etc.) may narrow the differential diagnosis, and diagnostic methods will be oriented differently (e.g., toward systemic lupus erythematosus [SLE], leishmaniasis, systemic mycoses).
PHYSICAL EXAM FINDINGS
• Dermatologic examination for identifying erosive and ulcerative lesions, and general physical examination to detect signs of underlying systemic diseases.
• The clinician should take note of primary lesions such as vesicles, bullae, and pustules and the distribution of the lesions (e.g., involvement of the mucosa). This information can suggest a specific group of diseases.
ETIOLOGY AND PATHOPHYSIOLOGY
Variable, depending on underlying cause.
• Congenital, hereditary, and conformational defects: for example, ulcerations can result from skin friction (e.g., intertrigo) or can be secondary to abnormal fragility of the dermoepidermal junction (e.g., epidermolysis bullosa).
• Infectious diseases (bacterial, viral, parasitic, fungal, rickettsial): some organisms infect and lyse keratinocytes (e.g., herpesvirus) or can cause epidermal necrosis secondary to either vasculitis (e.g., canine Rocky Mountain spotted fever) or a substantial inflammatory reaction, leading to ulcerative dermatitis.
• Immune-mediated disorders: ulcers may follow the rupture of vesicles and bullae caused by the action of antibodies.
• Environmental injuries (e.g., coagulation necrosis of the epidermis/dermis associated with thermal or chemical burns results in ulcerations)
• Secondary to systemic diseases (e.g., uremia resulting from renal failure may cause oral ulceration).
• Ischemic disorders: any dermatopathy that interferes with vascular supply of the skin can potentially cause ulcers secondary to skin necrosis.
• Neoplasia: ulcerations noticed in skin tumors, such as cutaneous epitheliotropic lymphoma or squamous cell carcinoma (SCC), are usually secondary to the infiltration of the skin by neoplastic cells and often correlate with the aggressiveness of the tumor.
DIAGNOSIS 
DIAGNOSTIC OVERVIEW
A definitive diagnosis is required in order to institute the appropriate treatment regimen.
DIFFERENTIAL DIAGNOSIS
• Congenital and hereditary: idiopathic facial dermatitis of Persian and Himalayan cats, aplasia cutis, epidermolysis bullosa (EB), familial canine dermatomyositis
• Infectious diseases: demodicosis, flea bite hypersensitivity, feline mosquito bite hypersensitivity, fly dermatitis; systemic mycoses, sporotrichosis, phaeohyphomycosis, zygomycosis, candidiasis, dermatophyte granuloma, pseudomycetoma, protothecosis, pythiosis, aspergillosis; deep pyoderma, mucocutaneous pyoderma, pyotraumatic dermatitis; feline leukemia virus (FeLV), feline cowpox, feline calicivirus (FCV), feline herpesvirus (FHV); canine Rocky Mountain spotted fever, leishmaniasis
• Immune-mediated disorders: pemphigus, bullous pemphigoid, erythema multiforme, toxic epidermal necrolysis, vasculitis, lupus erythematosus, EB acquisita, cold-agglutinin disease, cutaneous drug eruption
• Systemic diseases: superficial necrolytic dermatitis (hepatocutaneous syndrome), calcinosis cutis, uremia
INITIAL DATABASE
• Cytologic examination of any exudate contents: bacteria, inflammatory cells, acantholytic keratinocytes (pemphigus), fungal organisms
TREATMENT 
PEARLS & CONSIDERATIONS 
COMMENTS
• Considering the wide range of treatments, make a definitive diagnosis to correctly address the disease and prevent adverse effects of an improper treatment trial.
• Primary lesions (e.g., vesicles, bullae, and pustules) or skin surrounding erosion/ulcer should be sampled when skin biopsy is performed.
Ulcers, Oral Mucosal
BASIC INFORMATION 
CLINICAL PRESENTATION
PHYSICAL EXAM FINDINGS
• Faucitis (inflammation of the archway between the pharyngeal and oral cavities [formed by the tongue, anterior and posterior tonsillar pillars, and soft palate])
ETIOLOGY AND PATHOPHYSIOLOGY
• Metabolic causes: renal failure (uremia; common), diabetes mellitus, hypothyroidism, hypoparathyroidism
• Immune-mediated disease: oral ulcers occur with pemphigus vulgaris (90% of cases), bullous pemphigoid (80% of cases), systemic lupus erythematosus (SLE) (50% of cases), and discoid lupus erythematosus and can also be drug-induced (toxic epidermal necrolysis)
• Traumatic: foreign body, electric cord shock, malocclusion, “gum chewer’s disease“ (chronic chewing of cheek)
DIAGNOSIS 
DIFFERENTIAL DIAGNOSIS
• History, physical, and oral exam can differentiate foreign bodies, malocclusions, toxin/chemical exposure, and electrical burns.
ADVANCED OR CONFIRMATORY TESTING
• Serologic titers or other tests (e.g., PCR for infectious agents such as FeLV, herpesvirus) or systemic immune-mediated disease (e.g., antinuclear antibody titer for SLE)
• Oral radiographs: evaluation for concurrent osteomyelitis secondary to severe periodontal disease or bony involvement from malignant neoplasia
TREATMENT 
ACUTE GENERAL TREATMENT
• Nutrition: esophagostomy or gastrostomy feeding tubes (see pp. 1269 and 1270) may be required if oral disease or pain is resulting in steadfast and prolonged anorexia.
CHRONIC TREATMENT
• For idiopathic conditions (i.e., CUPS, LPS), meticulous dental care to prevent plaque accumulation is necessary. In addition, dental extractions (partial, caudal, or full mouth) may be necessary to remove the source of inflammation.
• Immunosuppressive drug therapy (e.g., corticosteroids, azathioprine) may be required for immune-mediated diseases.
Mason IS. Erosions and ulcerations. In: Ettinger SJ, Feldman EC, editors. Textbook of veterinary internal medicine. ed 6. St Louis: Elsevier Saunders; 2005:46-50.
Smith MM. Oral and salivary gland disorders. In: Ettinger SJ, Feldman EC, editors. Textbook of veterinary internal medicine. ed 6. St Louis: Elsevier Saunders; 2005:1290-1297.
Umbilical Hernia
BASIC INFORMATION 
CLINICAL PRESENTATION
DISEASE FORMS/SUBTYPES
• Omphalocele:
○ Large midline umbilical hernia and skin defect that allow abdominal organs to protrude externally. The umbilical sac is merely a thin transparent membrane (amniotic sac). The membrane is attached to the hernia edges and may rupture easily. Most affected puppies die or are euthanized before treatment is sought.
TREATMENT 
ACUTE GENERAL TREATMENT
PEARLS & CONSIDERATIONS 
COMMENTS
• There are usually no clinical signs associated with umbilical hernias. Correction is usually an elective procedure.
PREVENTION
• Consideration should be given to avoiding breeding affected dogs or cats, because this condition is usually an inherited defect.
Unerupted Teeth
BASIC INFORMATION
ETIOLOGY AND PATHOPHYSIOLOGY
• Complications leading to abnormal tooth eruption are many and varied: primary defects in the eruptive process, genetic/traumatic displacement of the tooth bud or surrounding bone, mechanical obstruction from adjacent structures, regional odontogenic and nonodontogenic neoplasia.
• The most commonly unerupted teeth in the dog are the mandibular first premolar and third molar teeth.
• Endocrine abnormalities (hypothyroidism, cretinism, hypogonadism, mongolism, hypopituitarism, hyperparathyroidism) can prevent or slow the eruption of teeth.
• Unerupted teeth can incite dentigerous cyst formation: an epithelial-lined soft tissue is attached to the cementoenamel junction of an unerupted tooth, with the crown protruding into the fluid-filled cyst, causing pressure resorption of alveolar bone, displacement of adjacent teeth, abscess, and fistulation.
DIAGNOSIS
DIAGNOSTIC OVERVIEW
Dental radiography is necessary to differentiate unerupted teeth from missing teeth.
TREATMENT
ACUTE AND CHRONIC TREATMENT
• Some unerupted teeth can be orthodontically coaxed into position if tooth, patient, and owner are willing.
• To prevent dentigerous cyst development, surgically extract unerupted teeth without eruption potential. Curettage of the extraction site is recommended to remove remnant odontogenic tissue. Postoperative radiographs ensure complete removal of all tooth structures.
• If a dentigerous cyst is present, the tooth and cyst are removed en bloc. If this is not possible, extensive curettage to remove all epithelial cyst lining is mandatory because small islands of remaining epithelium can lead to cyst reoccurrence or malignant transformation. The débrided cyst cavity need not be filled with osteopromotive materials; natural bone remodeling will likely be clinically adequate.
• Administration of antibiotics is not usually necessary after the extraction procedure unless another medical condition or extensive tissue trauma at the extraction site is present.
Gioso MA, Carvalho VG. Maxillary dentigerous cyst in a cat. J Vet Dent. 2003;20:28.
Mulligan TW, Aller MS, Williams CA. Atlas of canine and feline dental radiography. Trenton, NJ: Veterinary Learning Systems, 1998;91-103. 188–189.
Harvey CE, Emily PP. Small animal dentistry. St Louis: Mosby, 1993;276-281.
