Lecture: Keratinization disorders/seborrhea Flashcards Preview

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Flashcards in Lecture: Keratinization disorders/seborrhea Deck (45)
1

Layers of keratinization

  1. keratinized squames
  2. granule cell layer
  3. prickle cell lalyers
  4. basal cell laer
  5. basal lamina

2

Cornification

  1. formation of cornified envelope
  2. synthesis of keratohyalin
  3. formation of lamellar bodies 
  4. keratinization

*takes about 21-22 days

3

Hormonal regulation of sebum production

  • increased by androgens, thyroid and progesterone
  • decreased by corticosteroids, estrogens, suppressing adrogens

4

Sebum productions and dietary influence

  • fat deficiency
    • initial dec then inc in sebum production
  • most dogs need a combo of saturated and unsaturated fats
  • low levels of vitamin A
    • dec sebum production....?

5

Sebum composition

  • sterol
  • diester waxes
  • free cholesterol
  • triglycerides
  • fatty acids

6

Seborrhea sicca

  • excessive scale formation (dry skin)

7

Seborrhea oleosa

  • Excessive secretion of grease on skin and hairs

8

seborrheic dermatitis

  • excessive presence of scales or grease with inflammation

9

Primary seborrhea

  • american cocker
  • english springer spaniel
  • inherited dz
  • CS may be from birth

10

Secondary seborrhea

  • Internal or external stimuli (Inflammation)
    • altered epidermal proliferation, differentiation and desquamation (cornification)

11

pathogenesis of seborrhea

  • inflammation
    • histamine
    • cytokins
    • LTB4 and PGE2
  • Endocrinopathies
    • hormones
  • Nutrition
    • glucose proteins
    • fatty acids
    • vitamins, mineral
  • Environment
    • bathing
    • lipids/water

12

Clinical signs

  • Seborrhea sicca
  • Seborrhea oleosa
  • Seborrheic dermatitis
  • Ceruminous otitis
  • Secondary infestations

13

Primary causes Seborrhea

  • idiopathic
  • zinc responsive dermatitis type 1
  • schnauzer comedo syndrome
  • Epidermal dysplasia
  • Vitamin A responsive seborrhea

14

Secondary seborrhea

malassezia dermatitis

15

TX primary idiopathic seborrhea

Topical

Systemic

  • Topical
    • keratolytic/keratoplastic shamppos
    • antimicrobial shampoos
  • Systemic
    • oral retinoids
    • fatty acids
    • antimicrobials

16

Zn responsive dermatosis

Primary

  • breeds
    • alaskan malamute, husky, samoyeds
  • pathogenesis
    • inherited inpairment to metabolize zn
  • CS
    • age 1-3 years old
    • erythema, alopecia, crust, scales, hyperkeratotic foot pads
    • mucocutaneous junctions of face
    • malassezia and back infections common

17

Zn responsive dermatosis

Type II (Secondary)

  • Breeds
    • rapidly growing large breeds
  • Pathogenesis
    • nutrition
  • CS
    • thick, well demarcated plaques and crusts
    • periocular and perioral areas and genitalia
    • malassezia and bacterial infections common

18

Zn responsive dermatosis

TX

Topical

Systemic

  • Topical
    • kertolytic/keratoplastic shampoos
    • antimicrobial shampoos
  • Systemic
    • Zn supplement
    • antibiotics, antifungals

19

Schnauzer comedo syndrome

  • Breed
    • schnauzer
  • pathogenesis
    • unknown
  • CS
    • multiple comedones on dorsal midline
    • alopecia, erythema, crusted papules, follicular cysts
    • secondary infections

20

Schnauzer comedo syndrome

TX

Topical

Systemic

  • topical
    • karotolytic/keratoplastic shampoos
    • antimicrobial shampoos
  • systemic
    • oral retinoids (helps with kertinization)
    • antimicrobials

21

Malassezia spp

  • broad based
  • M. pachidermatis
  • Commensal of skin and ears
  • inc numbers in humid and warm conditions
  • secondary to other dz
  • malassezia hypersnesitivity

22

Malassezia spp has a commensal relationship with....

Staphylococci

23

Malassezia spp

Predisposing factors

  • humidity
  • breed
  • barrier changes
  • malassezia (unlike Candida) not subject to inhibitory effects of bacteria

24

Yeast numbers do not always relate to....

severity of clinical signs

25

malassezia Clinical presentation

  • Pruritus/erythema
  • scaling/seborrhea
  • paronychia
  • lichenification/hyperpigmentation
  • ventral body
    • neck, axillae, abdomen
  • face/ear pinnae
  • feet/forelegs
  • skin folds
  • otitis externa/media

26

malassezia dx

  • swabs
  • tape
  • impression smear

*fix sample to remove some fat....

27

Topical tx

seborrhea sicca

  • moisturizing
    • emollient vs. humectant
  • hypoallergenic
  • oatmeal and lanolin
  • sulfur +/- salicylic acid
  • antimicrobial

28

Topical tx

Seborrhea oleosa

  • selenium sulfate
  • sulfur +/- salicylic acid
  • Tar
  • Benzoyl peroxide
  • Antimicrobial

29

Keratoplastic

  • dec DNA => dec mitosis => dec cell ontogenesis

30

Keratolytic

  • dec cohesion between corneocytes => inc desquamation

31

Emollient

  • Moisturize skin => dec TEWL (trans epidermal water loss)

32

Humectant

  • moisturize the skin => dec TEWL and recall water from dermis and environment
  • more powerful than an emollient

33

Benzoyl peroxide

  • Keratolytic: benzoic acid
  • Antibacterial
  • no antifungal
  • degreasing
  • aggressive => irritant
  • bleaching agent

34

Selenium sulfate

(selsun blue)

  • Keratolytic: dec hydrogen bonds between keratines
  • Keratoplastic: dec cellular turn-over
  • Degreasing
  • Antifungal: Malassezia

35

Sulfur

  • Keratolytic: hydrogen sulfate
  • Keratoplastic: interaction with cysteine in keratinocytes
  • Degreasing
  • Antimicrobial and antiparasitic
    • pentatonic acid and hydrogen sulfate
    • antibacterial and antifungal

​​*DOES EVERYTHING!!!!

*STINKS

36

Salicylic

also selsun blue....?

  • Shampoo 0.1-2%
    • Keratoplastic
    • Antipruritic
    • Bacteriostatic
  • Shampoo 3-6%
    • keratolytic

37

Sulfur + salicylic acid

Synergistic action

38

Tar

  • shampoo
  • keratolytic
  • keratoplastic
  • degreasing
  • side effects
    • malodourous
    • Irritant and pohtosensitizing
    • carcinogenic

39

Emollients

 

  • Mainly oils
    • vegetable oils
    • animal oils
    • silicon, waxes and hydrocarbons
  • apply after shampoo

40

Humectants

  • Hygroscopic agents
    • propylene glycol
    • Glycerin
    • Colloidal oatmeal
    • Urea
    • Sodium lactate
    • Lactic acid

*Colloidal oatmea

41

Phytosphingosine

  • Shampoos, lotions, etc
  • Pro-ceramide: naturally present in skin
  • Anti-inflammatory
  • Antimicrobic

42

Miscellaneous

  • Zinc gluconate
    • anti-seborrheic
    • inhibitor of 5alpha-reductase
      • dec sebum production
  • Vitamin B6
    • dec syndergistically with Zn
  • Essential fatty acids
    • dec TEWL

43

Novasomes and spherulites

  • nano particles
  • adheres to skin and hairs
  • slow release of activ ingredient

44

Antimicrobial shampoo

summary

  • Sulfur
    • bacteria
    • yeast
  • Chlorahexidine
    • bacteria only
  • Benzoyl peroxide
    • bacteria only
  • Miconazole
    • bacteria
    • yeast
  • Selenium sulfate
    • yeast only

45

Systemic treatment

  • Ketoconazole
  • Itraconazole
  • Fluconazole
  • Terbinafine