Dermatology

Rain scald (dermatophilosis), ringworm (dermatophytosis), insect bite hypersensitivity, sarcoids, and pastern dermatitis are among the most frequently diagnosed skin conditions. Accurate diagnosis requires lesion distribution assessment, cytology, culture, or biopsy depending on the presentation.

Sarcoids are the most common equine skin tumor and are associated with bovine papillomavirus. Diagnosis is typically clinical but may require biopsy. Treatment options include surgical excision, cryotherapy, topical chemotherapy, immunotherapy, and laser ablation, chosen based on type, location, and number.

Biopsy is indicated when clinical and cytologic findings are inconclusive, when lesions fail to respond to initial therapy, or when immune-mediated or neoplastic conditions are suspected. Proper site selection and handling improve diagnostic yield.

Insect bite hypersensitivity, particularly to Culicoides midges, is the most common allergic skin disease. Environmental allergens and contact irritants also contribute. Management combines insect control, environmental modification, and pharmacologic treatment to reduce inflammation and pruritus.

Rain scald presents as matted crusts with a characteristic paintbrush appearance on the dorsum. Cytology showing branching filamentous organisms confirms Dermatophilus congolensis. Differential diagnoses include dermatophytosis, pemphigus foliaceus, and photosensitization.

Adequate protein, essential fatty acids, zinc, copper, and biotin support coat quality and skin barrier function. Nutritional deficiencies can predispose to poor wound healing, dull coat, and increased susceptibility to infection.