Dermatology Lecture # 2 pharm.txt
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. What would you like to do?
What are the types of skin?
- Mucous membrane
What is Mucocutaneous skin?
At the junction of the mucous membrane, hairyskin, lips, and tongue
What is Mucous membrane
Lining the inside of body orifices
What is Glabrous skin?
- Skin without hair
- Epidermal layer 1.5 mm; dermis 3 mm
What is Hairy skin?
- Skin with hair
- Epidermial layer 0.07 mm; dermis 1.5 mm
Where are medications absorbed on the skin?
Penetrate stratum corneum, enter remaining epidermis / dermis
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
- Chemical / physical properties of vehicle
- Thickness/hydration of epidermis
- Disease/damaged skin
What type of skin medications are most likely to be absorbed?
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
How does hydration effect absorption
The more hydrated, the better absorption
How does occlusion effect absorption
Occlusive dressings will cause the drug to be absorbed better, you may not always want this
How does damaged skin effect absortion
What are the types of vehicles for medication absorptions
Ointments, emulsions, liquids
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
What ia an emulsion?
Mixture of two immiscible substances
What are the types of emulsions?
Creams and foams
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
What are the properties of a Foam
- An emulsion
- Liquid and gas
- Easy to apply to hairy areas
What are types of Liquids
Lotions, gels, oils
What is atopic dermatitis?
- Chronic inflammatory pruritic condition
- Genetically predisposed individuals
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
What is the pathogenisis of atopic dermatitis
Hypersensitivity to environmental allergensOverproduction of IgE by helper T cellsTriggers immune response and release of cytokines
What are the typical sites of atopic dermatitis in an infant
Infant - Extensor parts of extremities (knuckles); cheeks of face
What are the typical sites of atopic dermatitis in 2 years to preteen
Flexural areas: neck, antecubital & popliteal spaces
What are the typical sites of atopic dermatitis in Puberty to adulthood
Forehead, periorbital areas; hands/wrists; feet/ankles
What are the GOALS OF THERAPY for atopic dermatitis
Control itching and scratchingTreat any inflammation or infectionRestore normal skin barriermaintain skin integrity; limit discomfort
Is there a cure for atopic dermatitis
No cure; most children outgrow symptoms
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***
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
How does Environmental conditions effect atopic dermatitis
- AD worse during dry winter, hot humid summer
- Avoid occlusive clothing, irritating fabrics (wool)
- Wear cotton
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
How does Ultraviolet light effect atopic dermatitis
- UV light (sunshine) may offer some benefit
- Avoid sunburn
When are Antibiotics used with atopic dermatitis
To treat secondary infections
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
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
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
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
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
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
What are the contrainindications of corticosteroids
Viral infections of the skin
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
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
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
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
What are tacrolimus (Protopic) and pimecrolimus (Elidel) used for?
- Atopic dermatitis
- reduces T cell response = less inflammation
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
What are Kerotolytic Agents used for
- Promote shedding of the horny layer of skin
- Effects range from peeling to extensive desquamation of stratum corneum
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
What is the Keratolytic Agent Imiquimod (Aldara) and podofilox (Condylox) used for
- For genital and perianal warts
- Can be applied by patient
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
What patients are OTC wart remover contraindicated
diabetes, impaired circulation , children < 2 yo , pregnancy
How does salicylic acid treat warts?
Dissolves intracellular cement binding scales to stratum corneum
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
Who should not use salicylic acid for warts
- Contraindicated: diabetes, impaired circulation, children < 2 years of age
- Causes site irritation
How does sulfur treat warts?
Promotes peeling and drying
How should sulfer medications be used for warts?
Forms: lotions, gels, shampoos
What are other uses of sulfer medications?
Also used to treat acne, dandruff, psoriasis, and seborrheic dermatitis
What are other comon wart removers?
- Banana peel
- Duct tape
- Coins, rubbing
- Talking it off
How does Benzoyl peroxide work for acne
Oxidizes bacterial protein
What are the common topical acne preparations?
Benzoyl peroxideSulfur, resorcinol, salicylic acidAzelaic acidTretinoin (retin A, retinoic acid)Antibiotics
How does Sulfur, resorcinol, salicylic acid work for acne
Kerolytic and mildly antibacterial
How does Azelaic acid work for acne
Interfers with DNA synthesis in some bacteria
How does retinoin (retin A, retinoic acid) work for acne
Comedolytic agent, follicular wall cell turnover
What topical Antibiotics are used for acne treatment
Clindamycin, erythromycin, tetracycline
What are the common SYSTEMIC ACNE PREPARATIONS?
- Oral antibacterial agents
- Oral contraceptives
- Antiandrogen (androgen receptior blocker)
What are the common systemic antibiotics for acne?
Clindamycin, erythromycin, tetracycline
How do systemic antibiotics for acne work?
Significantly decreases free fatty acids in skin lipids
How do oral contraceptive treat acne?
Decrease androgen levels thus sebum is decreased
What are the common Antiandrogens (androgen receptor blockers) used to treat acne?
spironalactone (Aldactone), flutamide (Eulexin)
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
How does POISON IVY, OAK, SUMAC cause skin rashes?
Contact dermatitis immunologically mediatedErythematous, vesicular, pruritic lesions
What is the treatment for poison oak, sumac, poison ivy?
- Drying lotions, gels
- Antihistamines (hydroxyzine, diphenhydramine)
- Cortisone medications – Topical & Systemic (prednisone)
What should you know about poisonous leaves
These trees are deciduous so remember this is child comes in the fall
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
What are characterisitcs of DIAPER RASH
- Secondary to urine contact with skin
How do you manage diaper rash
- Change diaper when wet, air dry skin
- Apply barrier cream
What is Candida
Caused by yeast
What is the management for candida
- Change diaper when wet, air dry skin
- Apply nystatin cream or ointment
What is IMPETIGO?
- Skin infection at site of skin break caused by streptococcus and staphylococcus
How does impetigo present?
Presentation: Initially small, erythematous papules which enlarge, become moist, develop honey yellow crusts on red base.
How is impetigo treated?
Treatment: oral antibiotics, antibacterial soap, antibacterial ointment
What is psorias?
Thickened, erythematous, scaling plaques
What is the cause of psorias?
- Cause unknown but immune system implicated
- Activates disordered growth of keratinocytes
- Also significant genetic component
What is the topical treatment for psorias?
- Emollients/keratolyticsTopical corticosteroids
- How do topical treatments for psoriasis work?
- Adjunct role: erythema, pruritus, scaling
What are the common psoriasis medications?
Cytostatic productsCoal tar / UV light; anthralin, calcipotriene, acitretin, tazarotene
What Systemic Therapy should you used for psoriasis?
Immune suppression - Cyclosporine and Tacrolimus
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
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