Dermatology Lecture # 2 pharm.txt

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Dermatology Lecture # 2 pharm.txt
2010-03-25 23:15:36
Lecture # 2 Dermatological Lectures

Pharmacology Lecture-dermatology
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  1. What are the types of skin?
    • Mucocutaneous
    • Mucous membrane
    • Glabrous
    • Hairy
  2. What is Mucocutaneous skin?
    At the junction of the mucous membrane, hairyskin, lips, and tongue
  3. What is Mucous membrane
    Lining the inside of body orifices
  4. What is Glabrous skin?
    • Skin without hair
    • Epidermal layer 1.5 mm; dermis 3 mm
  5. What is Hairy skin?
    • Skin with hair
    • Epidermial layer 0.07 mm; dermis 1.5 mm
  6. Where are medications absorbed on the skin?
    Penetrate stratum corneum, enter remaining epidermis / dermis
  7. What affects the absorption of medications on the skin
    • Drug molecular weight, particle size, solubility – if they are lipiphilic they are likely to get absorbed
    • Drug concentration in the vehicle
    • Vehicle
    • Chemical / physical properties of vehicle
    • Thickness/hydration of epidermis
    • Occlusion
    • Disease/damaged skin
  8. What type of skin medications are most likely to be absorbed?
  9. What is the “vehicle”
    This is what the active agent is placed in, it is important in how something is absorbed, petroleum based is absorbed quickly
  10. How does hydration effect absorption
    The more hydrated, the better absorption
  11. How does occlusion effect absorption
    Occlusive dressings will cause the drug to be absorbed better, you may not always want this
  12. How does damaged skin effect absortion
    Absorbed faster
  13. What are the types of vehicles for medication absorptions
    Ointments, emulsions, liquids
  14. What are the properties of an ointment?
    • Lipophilic drug in a vehicle
    • Vehicle: petrolatum, mineral oil, wax, organic alcohol
    • High release of drug into skin
  15. What ia an emulsion?
    Mixture of two immiscible substances
  16. What are the types of emulsions?
    Creams and foams
  17. What are the properties of Creams
    • An emulsion
    • Oil in water: more cosmetic
    • Water in oil: more occlusive
    • O/W cannot be washed off with water while W/O can
  18. What are the properties of a Foam
    • An emulsion
    • Liquid and gas
    • Easy to apply to hairy areas
  19. What are types of Liquids
    Lotions, gels, oils
  20. What is atopic dermatitis?
    • Chronic inflammatory pruritic condition
    • Genetically predisposed individuals
  21. What are the phases of atopic dermatis
    • Acute phase - Erythema, papulovesicular lesions, oozing, crusting
    • Chronic phase - Lichenified skin, pigmentary alteration, < exudative, vesicular lesions than acute, thickened skin, more prone to fissures
  22. What is the pathogenisis of atopic dermatitis
    Hypersensitivity to environmental allergensOverproduction of IgE by helper T cellsTriggers immune response and release of cytokines
  23. What are the typical sites of atopic dermatitis in an infant
    Infant - Extensor parts of extremities (knuckles); cheeks of face
  24. What are the typical sites of atopic dermatitis in 2 years to preteen
    Flexural areas: neck, antecubital & popliteal spaces
  25. What are the typical sites of atopic dermatitis in Puberty to adulthood
    Forehead, periorbital areas; hands/wrists; feet/ankles
  26. What are the GOALS OF THERAPY for atopic dermatitis
    Control itching and scratchingTreat any inflammation or infectionRestore normal skin barriermaintain skin integrity; limit discomfort
  27. Is there a cure for atopic dermatitis
    No cure; most children outgrow symptoms
  28. What is the management strategy for atopic dermatitis?
    • Hygiene - Literature varies on frequency of baths
    • Agree on lukewarm water, gentle soap & shampoo (Dove, Tone, Caress, Aveenobar, Neutrogena)
    • Moisturizers - Applied frequently
    • Check labels: avoid alcohol containing products
    • Avoid fragrances and dyes ***hypoallergenic***
  29. What type of creams would you want to apply
    • You do not want a lotion with the first ingredient as water because the water will evaporate very quickly
    • Need petroleum based products
  30. How does Environmental conditions effect atopic dermatitis
    • AD worse during dry winter, hot humid summer
    • Avoid occlusive clothing, irritating fabrics (wool)
    • Wear cotton
  31. How do you handle Dietary management with atopic dermatitis
    • Discourage food introduction prior to 4 months of age
    • Avoid known allergens
    • tree nuts, peanuts, shellfish, fish, eggs, orange juice, cow’s milk
  32. How does Ultraviolet light effect atopic dermatitis
    • UV light (sunshine) may offer some benefit
    • Avoid sunburn
  33. When are Antibiotics used with atopic dermatitis
    To treat secondary infections
  34. What is the treatment and care of atopic dermatitis?
    Topical Corticosteroid Usage - Relieve inflammation and itchingApplication Immediately after the bath before moisturizersApply sufficient amount to cover lesion only
  35. What should you remember about topical corticosteroid absorption
    • Systemic absorption proportional to duration of use and surface area covered
    • permeability: scalp, axilla, face, eyelids, neck, perineum, genitalia, inflammed skin
    • permeability: back, palms, soles, intact skin
  36. How do ointments and creams differ
    • Ointments are more potent than creams because of their occlusive nature
    • Occlusiveness increases effect 10-fold
    • Occlusive dressing enhance effect
  37. How are corticosterois classified?
    • Classified from less to more potent
    • Some resources list classes I – VII, others list by potency (low, intermediate, high, very high)
    • Using resources, in your peripheral brain create a chart with 1 – 2 meds of each category for future reference
  38. What strength of corticosteroid should you use for atopic dermatitis
    • Use least potent product which is effective
    • Use low potency products for face, genitalia, axillae
    • Prolonged usage results in hypopigmentation
    • Adults 2 weeks, children < 6yo 1 week
  39. What does the percent of concentration of corticosteroids tell you about the drug?
    • Percent of concentration is not equivalent
    • 0.05% betamethasone dipropionate is high potency while 2.5% hydrocortisone is low potency
  40. What are the contrainindications of corticosteroids
    Viral infections of the skin
  41. Why are antihistamines used for atopic dermatitis
    Antihistamines relieve itching from hives caused by histamine releaseCause of the itching from atopic eczema is quite different from that of hives and involves mechanisms other than histamine
  42. What are side effects of antihistamines for atopic dermatitis
    • Classical antihistamines can cause some drowsiness, use of these at bedtime for short period may be useful to help the child sleep when they are itchy, but the sedative effects of these antihistamines do not persist with continued usage
    • No indication for the newer generation of antihistamines such as Claritin, Allegra, or Zyrtec since they provide little or no sedation
  43. How would you dose antihistamines for atopic dermatitis
    • Given at bedtime to limit scratch - itch cycle by inducing drowsiness and promoting sleep
    • Hydroxyzine (Atarax)
    • 0.6 mg/kg/dose q6h prn
    • Diphenhydramine (Benadryl)
    • 0.5-1.0mg/kg/dose Q4-6h prn
  44. What are topical Immunomodulators used for?
    Currently indicated for atopic eczema that does not respond to conventional therapy with skin care and low potency topical corticosteriodsNot a replacement for skin care but may provide an alternative to topical corticosteroids when those are not effective or require excessive use
  45. What are tacrolimus (Protopic) and pimecrolimus (Elidel) used for?
    • Atopic dermatitis
    • reduces T cell response = less inflammation
  46. What are the benefits of topical immunomodulators
    • No risk of the cosmetic changes associated with prolonged usage of topical corticosteroids
    • Not required continuouslywhere corticosteroids are required continuously
  47. What are Kerotolytic Agents used for
    • Promote shedding of the horny layer of skin
    • Effects range from peeling to extensive desquamation of stratum corneum
  48. What is the Keratolytic Agent Podophyllum resin used for
    • For condylomata acuminata: venereal warts
    • Only applied by care provider
    • Apply on wart surface x 60 minutes; wash thoroughly
    • Severe irritation at site of application if not removed
    • Repeat weekly up to 4 weeks
    • Contraindicated in pregnancy
  49. What is the Keratolytic Agent Imiquimod (Aldara) and podofilox (Condylox) used for
    • For genital and perianal warts
    • Can be applied by patient
  50. How do you use OTC WART REMOVERS
    Scrub to remove dead surface cellsApply on wart surfaceDo not apply to face, genitals, mucous membranes Causes site irritation
  51. What patients are OTC wart remover contraindicated
    diabetes, impaired circulation , children < 2 yo , pregnancy
  52. How does salicylic acid treat warts?
    Dissolves intracellular cement binding scales to stratum corneum
  53. How do you use salicylic acids to treat warts
    • Forms: disc, gel, ointment, plaster solution, patch
    • Apply to wart bid x 7 - 14 days until resolution occurs
    • Rub briskly after bath to remove dead surface cells
    • Do not apply to face, genitals, mucous membranes
  54. Who should not use salicylic acid for warts
    • Contraindicated: diabetes, impaired circulation, children < 2 years of age
    • Causes site irritation
  55. How does sulfur treat warts?
    Promotes peeling and drying
  56. How should sulfer medications be used for warts?
    Forms: lotions, gels, shampoos
  57. What are other uses of sulfer medications?
    Also used to treat acne, dandruff, psoriasis, and seborrheic dermatitis
  58. What are other comon wart removers?
    • Other
    • Banana peel
    • Duct tape
    • Coins, rubbing
    • Talking it off
  59. How does Benzoyl peroxide work for acne
    Oxidizes bacterial protein
  60. What are the common topical acne preparations?
    Benzoyl peroxideSulfur, resorcinol, salicylic acidAzelaic acidTretinoin (retin A, retinoic acid)Antibiotics
  61. How does Sulfur, resorcinol, salicylic acid work for acne
    Kerolytic and mildly antibacterial
  62. How does Azelaic acid work for acne
    Interfers with DNA synthesis in some bacteria
  63. How does retinoin (retin A, retinoic acid) work for acne
    Comedolytic agent, follicular wall cell turnover
  64. What topical Antibiotics are used for acne treatment
    Clindamycin, erythromycin, tetracycline
  65. What are the common SYSTEMIC ACNE PREPARATIONS?
    • Oral antibacterial agents
    • Oral contraceptives
    • Antiandrogen (androgen receptior blocker)
  66. What are the common systemic antibiotics for acne?
    Clindamycin, erythromycin, tetracycline
  67. How do systemic antibiotics for acne work?
    Significantly decreases free fatty acids in skin lipids
  68. How do oral contraceptive treat acne?
    Decrease androgen levels thus sebum is decreased
  69. What are the common Antiandrogens (androgen receptor blockers) used to treat acne?
    spironalactone (Aldactone), flutamide (Eulexin)
  70. What should you know about isotretinoin (accutane)
    • Limited to severe, refractory acne
    • Hepatic conjugation, biliary excretion
    • Monitor CBC, liver enzymes, TG, cholesterol prior to and weekly to bi-weekly until stable, then monthly
    • Stop if liver enzymes x 2 normal or TG >750 mg/dL
    • Absolutely contraindicated in pregnancy - Birth control mandatory, Pregnancy tests mandatory
  71. How does POISON IVY, OAK, SUMAC cause skin rashes?
    Contact dermatitis immunologically mediatedErythematous, vesicular, pruritic lesions
  72. What is the treatment for poison oak, sumac, poison ivy?
    • Drying lotions, gels
    • Antihistamines (hydroxyzine, diphenhydramine)
    • Cortisone medications – Topical & Systemic (prednisone)
  73. What should you know about poisonous leaves
    These trees are deciduous so remember this is child comes in the fall
  74. What if a child has a rash all over?
    If child has a rash all over they probably need prednisone because it is a systemic reaction
  75. What are characterisitcs of DIAPER RASH
    • Irritation
    • Secondary to urine contact with skin
  76. How do you manage diaper rash
    • Change diaper when wet, air dry skin
    • Apply barrier cream
  77. What is Candida
    Caused by yeast
  78. What is the management for candida
    • Change diaper when wet, air dry skin
    • Apply nystatin cream or ointment
  79. What is IMPETIGO?
    • Skin infection at site of skin break caused by streptococcus and staphylococcus
    • Contagious
  80. How does impetigo present?
    Presentation: Initially small, erythematous papules which enlarge, become moist, develop honey yellow crusts on red base.
  81. How is impetigo treated?
    Treatment: oral antibiotics, antibacterial soap, antibacterial ointment
  82. What is psorias?
    Thickened, erythematous, scaling plaques
  83. What is the cause of psorias?
    • Cause unknown but immune system implicated
    • Activates disordered growth of keratinocytes
    • Also significant genetic component
  84. What is the topical treatment for psorias?
    • Emollients/keratolyticsTopical corticosteroids
    • How do topical treatments for psoriasis work?
    • Adjunct role: erythema, pruritus, scaling
  85. What are the common psoriasis medications?
    Cytostatic productsCoal tar / UV light; anthralin, calcipotriene, acitretin, tazarotene
  86. What Systemic Therapy should you used for psoriasis?
    Immune suppression - Cyclosporine and Tacrolimus
  87. What do these common antibacterials treat : Bacitracin, Polymixin B
    • Polysporin, Neosporin, Mupirocin (Bactroban)
    • Bacitracin - Gram +
    • Polymixin B - Gram –
    • Polysporin - Bacitracin and polymixin- gram + and -
    • Neosporin - Gram + & - but…no strep, Pseudomonas
    • Mupirocin (Bactroban) - Strep & staph but…↑ MRSA resistance