Skin and Ear Disorders in Small Animal Nursing

Skin and Ear Disorders

Introduction

  • Course: Small Animal Nursing 1

  • Focus: Management of skin and ear disorders in small animals (primarily dogs and cats).

Skin Anatomy

  • Skin: The largest organ in the body, part of the integument system.

    • Composed of various parts:

      • Skin: Protects internal structures and regulates temperature.

      • Hair: Offers protection, contributes to thermoregulation.

      • Footpads: Specialized for weight-bearing and protection.

      • Nose pad: Unique structure aiding in sensation.

      • Claws: Protect digits and assist in movement.

  • Accessory organs (glands):

    • Mammary glands: Produce milk.

    • Sweat glands: Assist in thermoregulation.

    • Sebaceous glands: Produce oil for skin lubrication.

Functions of Skin

  • Protection from environmental threats (pathogens, UV radiation).

  • Sensation: Skin contains nerves that respond to touch, temperature, and pain.

  • Secretion: Glands secrete necessary substances (e.g., oils, sweat).

  • Storage: Acts as a reservoir for water and fat.

  • Thermoregulation: Helps maintain body temperature through sweating and blood flow regulation.

  • Production: Synthesis of Vitamin D when exposed to sunlight.

  • Communication: Body language can be conveyed through skin (e.g., blushing, fever).

  • Impairment: Any disruption in function can lead to skin diseases.

Structure of Skin

  • Three layers of skin:

    • Epidermis: 3-5 layers thick; contains the stratum corneum (horny layer) which is thickest in foot pads and noses.

    • Dermis (corium): Contains blood vessels, lymphatic vessels, and nerve endings; supports epidermis.

    • Hypodermis (subcutaneous layer): Composed of fat and connective tissue; insulation and energy storage.

Hair Anatomy

  • Components:

    • Shaft: Visible part of hair.

    • Root: Embedded in the skin.

  • Types of Hair:

    • Guard hairs: Longer and coarser, provide primary protection.

    • Wool hairs: Soft and insulating hairs.

    • Tactile hairs: Sensory hairs (whiskers).

  • Growth Cycle:

    • Continuous growth affected by factors like hormones, seasons, nutrition, and overall health.

Foot Pads

  • Structure: Tough layers of fat and connective tissue; specialized for weight-bearing.

  • Components:

    • Exocrine sweat glands.

    • Lamellar corpuscles for pressure sensitivity.

    • Conical papillae that cover the entire pad, comprising all five epidermal layers.

    • Types of footpads:

      • Carpal pads

      • Metacarpal and metatarsal pads

      • Digital pads

Claws

  • Structure:

    • Composed of keratinized cells from the ungual process.

  • Functions:

    • Protection: Prevents injuries.

    • Grip: Aids in climbing and holding objects.

    • Continuous Growth: Require regular trimming.

    • Retractable Claws: Present in cats for stealth and protection.

Ear Anatomy

  • Four main parts:

    • Pinna: External ear structure covered in skin and cartilage.

    • External ear canal: Modestly hairy, contains cerumen and sebaceous secretions.

    • Middle ear: Air-filled space for sound transmission.

    • Inner ear: Contains structures involved in balance and hearing.

Aural Hematoma

  • Definition: Condition resulting from trauma to the pinna, leading to blood vessel rupture and blood accumulation.

  • Symptoms: Painful swelling; separation of skin from cartilage.

  • Causes: Often secondary to itchy ears and excessive scratching.

  • Treatment Options:

    • Do Nothing: Not advisable due to pain.

    • Medical Management: May include medications to reduce inflammation.

    • Surgery: Drainage and suturing techniques may be employed.

Otitis Externa

  • Definition: Inflammation of the external ear canal.

  • Etiology:

    • Multifactorial disease influenced by primary causes, secondary causes, predisposing factors, and perpetuating factors.

  • Diagnosis:

    • Comprehensive history and physical examination.

    • Ear cytology: Microscopic examination of ear discharge.

    • Ear culture: To identify infectious agents.

    • Ear flush: Cleansing to remove debris.

    • Imaging: If condition is severe and chronic.

Treatment Goals for Otitis Externa

  • Alleviate discomfort and pain.

  • Remove debris and discharge.

  • Eliminate infection from external and middle ear.

  • Reverse chronic pathological changes, if possible.

  • Identify and treat the primary cause of the otitis.

Treatment Options for Otitis Externa

  • Ear cleaning: Regularly removing debris.

  • Topical Antimicrobials: Applied locally, may include systemic antimicrobials.

  • Topical Parasiticides: To eliminate ectoparasites.

  • Topical/Systemic Glucocorticoids: For inflammation reduction.

  • Systemic Immunomodulatory Medications: Target the immune response.

  • Surgery: Indicated in chronic or unresponsive cases.

Ectoparasites Overview

  • Types:

    • Ear Mites (Otodectes): Cause intense itching, visible on exam.

    • Mange (Demodex and Sarcoptes): Associated with hair loss and skin disease.

    • Fleas (Ctenocephalides felis): Bloodsuckers; cause pruritus; life cycles involve multiple stages (egg, larva, pupae, adult).

    • Ticks: Blood-feeding parasites; vectors for diseases.

    • Warbles and Maggots: Associated with fly infestations leading to larval infections in the skin.

    • Lice: Species-specific, often found in neglected animals.

Atopic Dermatitis

  • Definition: Chronic inflammatory condition linked to allergens, can affect skin and/or gastrointestinal tract.

  • Common Allergens: Pollen, grasses, food, house mites, etc.

  • Genetics: May have hereditary predisposition; onset typically between 1-5 years of age.

  • Clinical Signs:

    • Red, itchy skin affecting face, paws, and groin.

    • Chronic ear infections and potential gastrointestinal signs.

  • Diagnosis:

    • Rule out other conditions; skin and ear cultures; allergy testing.

  • Treatment Options:

    • Immunomodulating drugs (glucocorticoids, cyclosporine).

    • Immunotherapy (Cytopoint injections, hyposensitization).

    • Antihistamines; topical therapies; hypoallergenic diets.

Fungal Infections

  • Superficial Dermatomycoses:

    • Caused by fungi such as Microsporum gypseum and Trichophyton mentagrophytes.

    • Zoonotic potential; affects young and immunocompromised animals.

    • Clinical signs include scaly lesions and patchy hair loss.

  • Diagnosis:

    • Wood’s lamp examination; potassium hydroxide preparation; culture methods.

  • Treatment:

    • Localized lesions treated with antifungals; generalized cases require systemic treatment.

Pyodermas Overview

  • Types:

    • Superficial: Caused by normal flora overgrowth; often resolved without scarring.

    • Deep: More challenging to diagnose and treat; may become chronic or recurrent.

    • Acne: Presentation varies between species (canine vs. feline).

    • Impetigo: Affects young dogs in unsanitary conditions.

  • Diagnosis: Typically by appearance and skin cytology; cultures may identify causative agents.

  • Treatment: Usually involves antibiotics, topical therapies, and addressing underlying causes.

Anal Sacs

  • Structure: Located at 4 and 8 o'clock positions around the anus; lined with sebaceous glands.

  • Problems: Often related to infection or impaction; behavioral signs (scooting, licking).

  • Diagnosis: Physical examination for swelling and pain; may see purulent material.

  • Treatment: Manual expression, flushing, antibiotic therapy, and surgical intervention for chronic cases.

Skin Tumors

  • Benign Tumors:

    • Histiocytomas: Common in young dogs, may regress spontaneously.

    • Lipomas: Slow-growing and benign; surgical excision is often successful.

    • Papillomas: Often viral in origin, usually regress on their own.

  • Malignant Tumors:

    • Fibrosarcomas: Aggressive; requires wide surgical margins for removal.

    • Mast Cell Tumors: Can show varying behavior; surgical removal is the recommended approach.

    • Melanomas: Vary in growth potential; malignant types are highly invasive and require aggressive treatment (surgery, chemo).

Conclusion

  • Understanding the complexity of skin and ear disorders is essential for effective diagnosis and management in small animal practice. Following this comprehensive guide will provide a solid foundation for approaching these conditions.

Skin and Ear Disorders

  • Skin Anatomy: Largest organ; protects, regulates temp, contains hair, footpads, claws, glands.

  • Functions: Protection, sensation, secretion, thermoregulation, vitamin D production.

  • Ear Anatomy: Pinna, ear canal, middle and inner ear.

  • Common Conditions:

    • Aural Hematoma: Blood accumulation from trauma.

    • Otitis Externa: Infection of ear canal; treat with cleaning, antimicrobials.

    • Dermatitis: Inflammation from allergens; signs include itchy skin, ears.

    • Fungal Infections: Diagnosed via cultures; treat with antifungals.

    • Ectoparasites: Mites, fleas, and ticks; cause itching and skin issues.

  • Skin Tumors: Benign (e.g., lipomas) vs. malignant tumors (e.g., mast cell tumors).