Keratization Disorders (Santoro) Flashcards
Cornification
- Process takes about 21-22 days
- Forms the stratum corneum
- Keratinization → formation of lamellar bodies → synthesis of keratohyalin granules → formation of cornified envelop
Seborrhea
- Clinical sign, NOT a disease (but can be in the name of a disease, i.e. primary seborrhea)
- Nonspecific term that refers to almost any dermatosis
Hormonal regulation of sebum production
- Incr. by androgens, thyroid, progesterone
- Decr. by corticosteroids, estrogens
Dietary influence on sebum production
Fat deficiency → initial decr. and then incr. (experimental)
Factors controling sebum production
- Hormonal regulation
- Dietary influence
- Low levels of vitamin A
Sebum composition
- Sterol
- Diester waxes
- Free cholesterol
- Triglycerides
- Fatty acids
Seborrhea sicca
Excessive scale formation
Seborrhea oleosa
Excessive secretions of grease on skin & hairs
Seborrheic dermatitis
Excessive presence of scales of grease w/ inflammation
Cause of primary seborrhea
Inherited dz (genetic component). Clinical signs usually start at a very young age.
Cause of secondary seborrhea
Induced by diseases or external stimuli
Causes & pathogenesis of seborrhea
- Inflammation
- release of histamine, cytokines, LTB4, PGE2
- Endocrinopathies
- Hormones incr. cell proliferation
- Nutrition
- Environmental factors
- Excessive bathing
Clinical signs of seborrhea
- Generalized or localized
- Seborrhea sicca
- Seborrhea oleosa
- Seborrheic dermatitis
- Ceruminous otitis
- 2º infections
Types of primary seborrhea
- Idiopathic seborrhea
- Ichthyosis
- Zinc responsive dermatitis type I
- Feline idiopathic dermatitis
- Schnauzer comedo syndrome
- Acrodermatitis
- Exfoliative CLE
- Epidermal dysplasia
- Vit. A responsive seborrhea
- Sebaceous adenitis
Types of secondary seborrhea
- Allergy
- Pyoderma
- Dermatophytosis
- Malassezia dermatitis
- Scabies
- Demodicosis
- Pemphigus complex
- Zinc responsive dermatitis type II
- Endocrinopathies
- Cutaneous lymphoma
- Necrotic migratory erythema
- Feline acne
- Feline thymoma-associated exfoliative dermatitis
Primary (idiopathic) seborrhea pathogenesis
- Keratinization/cornification defect
- Not well understood
- Acceleration of keratinization process
Primary (idiopathic) seborrhea common breeds
- Cocker Spaniel
- English Springer Spaniel (?)
- Cavalier King Charles Spaniel
- Shar Pei
- Labrador Retriever
- West Highland White Terrier
Primary (idiopathic) seborrhea clinical signs
- Greasy skin w/ scales, comedones, follicular casts, otitis
- Dry skin (Dobermans, Irish Setters)
- Skin infections common
Primary (idiopathic) seborrhea diagnosis
Exclusion of secodary seborrhea
Primary (idiopathic) seborrhea treatment
- Keratocytic/keratoplastic shampoo
- Antimicrobial shampoo
- Oral retinoids (isotretinoin)
- Fatty acids (topical or in food)
- Abx or antifungals
Zn responsive dermatosis type I breed predilection
- Alaskan malamute
- Samoyeds
- Siberian husky
Zn responsive dermatosis type I pathogenesis
Inherited impariment to absorb and metabolize zinc
Zn responsive dermatosis type I clinical signs
- 1-3 yrs old
- Erythema
- Alopecia
- White-grey scales and crusts
- Hyperkeratotic foot pads
- Mucocutaneous junctions of face and pressure points
- Malassezia and bacterial infections common
Zn responsive dermatosis type II predilection
Rapidly growling, large breed puppies
Zn responsive dermatosis type II pathogenesis
Unbalanced diet high in phytates or minerals that chelate zinc
Zn responsive dermatosis type II clinical signs
- Thick, well demarcated plaques & crusts
- Periocular and perioral areas & genitalia
- +/- enlarged lymph nodes
- Malassezia and bacterial infections common
Zn responsive dermatosis treatment
- Keratolytic/keratoplastic shampoos
- Antimicrobial shampoos
- Zn supplement
- Abx, antifungals
Schnauzer comedo syndrome clinical signs
- Multiple comedones on dorsal midline
- Alopecia
- Erythema
- Crusted papules
- Follicular cysts
- 2º infections
Schnauzer comedo syndrome treatment
- Keratolytic/keratoplastic shampoos
- Antimicrobial shampoos
- Oral retinoids (isotretinoin)
- Abx, antifungals
Malassezia species
- Budding yeast
- Commensal of skin and ears
- Incr. number in humid, warm conditions
- Commensal relationship w/ staph
Malassezia predisposing factors
- Incr. humidity, warm
- Primary dz that incr. sebum production, inflammation, and/or alter surface barrier
- allergies, keratinization defects, endocrinopaties, infection
- Skin folds
- Breed
Malassezia clinical presentation
- Pruritis/erythema
- Scaling/seborrhea
- Paronchia
- Lichenification/hyperpigmentation
- Ventral body (neck, axillae, abdomen)
- Face, ear pinnae
- Feet, forelegs
- Skin folds
- Otitis externa/media
Malassezia diagnosis
- Cytology
- Scotch tape
- Impression smear on oozing areas
- Swabs for ears
- (sample may be fatty so heat fix before Difquick)
Malassezia treatment
Kill the yeast and the seborrhea will go away
Seborrhea sicca topical treatment
- Moisturizing - emollient vs. humectant
- Hypoallergenic
- Oatmeal
- Lanolin
- Sulfur +/- salicylic acid
- Antimicrobial
Seborrhea oleosa topical treament
- Selenium sulfate
- Sulfur +/- salicylic acid
- Tar
- Benzoyl peroxide
- Antimicrobial
Keratoplastic
Decr. DNA → decr. mitosis → decr. cell ontogenesis
Keratolytic
Decr. cohesion between corneocytes → incr. desquamation
Emollient
Moisturize the skin → decr. transepithelial water loss
- Vegetable oils, animal oils, silicon, waxes, hydrocarbons
Humectant
Moisturize the skin → decr. transepithelial water loss and reall water from dermis and environment
- propylene glycol, glycerin, colloidal oatmeal, urea, sodium lactate, lactic acid
Benzoyl peroxide
- Keratolytic
- Antibacterial
- Degreasing
- Aggressive use can cause irritation
- Bleaching agent
Selenium sulfate
- Selson Blue
- Keratolytic
- Keratoplastic
- Degreasing
- Antifungal (malassezia)
Sulfur
- Keratolytic
- Keratoplastic
- Degreasing
- Antimicrobial
- Antiparasitic
- Antifungal
- Synergistic w/ salicylic acid
Salicylic acid
- Shampoo 0.1-2%
- Keratoplastic
- Antipruritic
- Bacteriostatic
- Shampoo 3-6%
- Keratolytic
- Synergistic w/ sulfur
Tar
- Keratolytic
- Keratoplastic
- Degreasing
- Side effects
- malodourous
- irritant and photosensitizing
- carcinogenic
Phytosphingosine
- Pro-ceramide
- naturally in skin
- Anti-inflammatory
- Antimicrobic
Novasomes & spherulites
- Nanoparticles
- Adhere to skin & hair
- Slow release of active ingredient
Systemic anti-fungals
- Ketoconazole
- Itraconazole
- Fluconazole
- Terbinafine
