Canine Atopy and Ectoparasites

• The second most common cause of skin disease in the dog is Atopy (Atopic Dermatitis).

Allergens

• Allergens that can cause chronic, inflammatory diseases include grasses, pollens, dusts, house mites, food, and other environmental pollutants.
• Clinical signs of atopic dermatitis include red, itchy skin, chronic ear infections, and GI symptoms.
• Allergies can be seasonal or non-seasonal.
• In food allergies, feeding trials may take 8-12 weeks for symptoms to resolve.
• Ectoparasites must be controlled during the entire year.

Ectoparasites

• Commonly diagnosed ectoparasites include ear mites, mange, fleas, warbles, ticks, lice, and myiasis (maggots).
• Ear mites feed on epidermal debris.
• Clinical signs of ear mites include black/brown musty exudate, pruritus, and wounds on face/ears.
• Blood-sucking ectoparasites that feed sporadically on mammals and birds are fleas.
• Areas to check for fleas on a patient include tail, head, inner thigh, and neck.
• Small pepper-like granules in a patient's hair/on their skin that turn red when water is applied are flea excrement containing traces of blood.
• Treatments for fleas include sprays, dips, shampoos, and systemic medications, and are frustrating because it is a very long process requiring killing all stages of the life cycle and treating all pets.
• Three primary diseases under the general term "mange" include demodectic mange (Demodex), sarcoptic mange (Sarcoptes), and notoedric mange.
• Defining features of demodectic mange include alopecia, non-pruritic, and erythema.
• Demodex is non-pruritic, while Sarcoptes is extremely pruritic.
• The defining features of sarcoptic mange include pruritus and red, crusty lesions.
• The cycle of the cuterebra: the fly lays eggs in the soil, eggs mature into grub, which penetrate the host's skin; larvae mature in a SQ space and breath through a fistula opening.
• Another name for cuterebra is warbles, and treatment involves incising the fistula, and removing the larva with hemostats.
• Another name for myiasis is maggots.
• Myiasis is a disease of neglect.
• Heavy-coated animals and warm/wet months are more at-risk conditions for myiasis.
• Treatment options for myiasis include clipping the hair, cleaning the wound, manually removing the larva, considering antibiotics, and keeping the pet indoors.
• Lice are host-specific and spend all their lives on the host.
• The other term for fungal infections is superficial dermatomycosis.
• The dermatophyte penetrates the skin and begins to proliferate on the surface of the hair shaft.
• The most common fungi for cats and dogs: Microsporum canis (ringworm).
• Characteristics of Microsporum canis infections include circular patches of alopecia (may be red & crusty), frequently on the face and head.
• Ways to diagnose fungal infections include Wood's lamp, KOH slide prep, and fungal culture.
• Pyodermas are bacterial infections that involve the skin.
• Categories of superficial pyodermas include acute moist dermatitis, and impetigo.
• Another name for acute moist dermatitis is hot spots, or skin fold pyoderma.
• Hot spots occur secondary to skin trauma.
• Owners should wash hands to prevent zoonosis when treating an animal for acute moist dermatitis.
• Impetigo lesions are nonpruritic and nonpainful.
• Characteristics of feline acne include swollen, painful chin, blackheads, and fever.
• Treatment options for feline acne include clip hair, antibacterial soap cleanse, Stridex pads, and systemic antibiotics.
• The most common sites for skinfold pyoderma are lips, facial folds, vulvar folds, tail folds (anywhere that skin is abundant).
• Treatment options for skinfold pyoderma include dry lesions, surgical removal of skin, topical antibiotics, and weight loss (if an animal is obese).
• Breeds commonly affected by skinfold pyoderma include pugs, Shar-Peis, spaniels (lip), Pekingese (facial), and obese dogs.
• Deep pyodermas involve Staphylococcus intermedius.
• Deep pyodermas: Juvenile pyoderma (puppy strangles), interdigital pyoderma (interdigital cysts), and generalized pyoderma (German Shepherd pyoderma).
• Clinical signs of deep pyodermas include papules & pustules with crusting, fever, and draining fistulas.
• Treatment options for deep pyodermas include daily cleaning of infected areas, systemic antibiotics, and antibiotic creams/sprays.
• The organism responsible for deep pyodermas is often drug-resistant.
• Common anal sac problems: impaction, chronic infection, and abscesses/rupture.
• Treatment options for anal glands: express, instill antibiotic ointment, lavage, administer oral antibiotics, or surgical removal.
• Other reasons a patient will "scoot" on the floor include urinary tract infections and possible parasites.
• Benign is defined as non-harmful.
• Malignant is defined as cancerous.
• Histiocytomas look like a small, button-like, pink nodule.
• Lipomas are round-oval, slow growing, and freely moveable.
• FNA stands for fine needle aspirate.
• Papillomas: smooth, white, elevated lesions in the oral mucosa that develop into a cauliflower-like growth.
• Treatment options for papillomas include surgical excision, crushing them, or autogenous vaccine (usually not needed).
• Papillomas are caused by DNA virus.
• Sebaceous cysts can occur in dogs of any age or sex.
• Sebaceous cysts are round, encapsulated, and exude gray, cheesy material.
• Basal cell carcinomas are single, small lesions, firm, and often ulcerated, on face, ears, lips, neck, and legs.
• Basal cell carcinomas are treated with wide surgical excision, with a fair prognosis that is less favorable if multiple lesions are present.
• Fibrosarcomas are firm, range in size, are rubbery on palpation, and adhered to underlying tissue.
• Treatment for fibrosarcomas entails wide surgical excision, and have a poor prognosis because they are invasive and metastasize quickly.
• Characteristics of feline fibrosarcomas include a mass that presents at the site of vaccination, 4-6 weeks after vaccination, and is highly invasive and malignant.
• Treatment for malignant skin tumors is radical surgical excision (often limb amputation).
• The prognosis for malignant skin tumors is poor.
• Mast cell tumors are isolated, firm nodules on the skin that fluctuate in size and may be ulcerated.
• Treatment for mast cell tumors includes surgical excision, prednisolone, and radiation.
• The prognosis depends on the presence of antihistamine.
• Benign melanomas are small, slow growing, hairless, and have dark pigmentation.
• Treatment for benign melanomas is surgical resection.
• The prognosis for benign melanomas is fair.
• Malignant melanomas are large, dome-shaped (barnacle-like), and immobile.
• Treatment for malignant melanomas is surgical resection.
• The prognosis for melanoma is poor because the disease usually metastasizes.
• Perianal tumors (adenomas/adenocarcinomas) are small, slow-growing tumors around the anus.
• Treatment for perianal tumors is surgical excision, castration, radiation, or cryotherapy.
• The prognosis is fair to poor.
• Squamous cell carcinomas are raised, ulcerated, cauliflower-like, and necrotic.
• Treatment for squamous cell carcinoma is surgical excision, radiation therapy, and cryosurgery.
• The prognosis is poor.