Studied by 11 people
Which areas of the body are more permeable?
scrotum, face, axilla, scalp (thinner skin)
What effect does occlusion have on efficacy?
increase
What is the most drying dermatologic vehicle?
tinctures
Which dermatologic vehicles are the least drying?
ointments
What kind of vehicle would you use for oozing, vesiculation, crusting?
tincture (drying)
What vehicle would you use in scaling, lichenificaiton, xerosis?
ointments (least drying)
What four major factors affect acne?
inc sebum production
alteration in keratinization process and hyper proliferation of ductal epidermis
bacterial colonization (propionibacterium acnes)
release of inflammatory mediators in acne sites
How does stress affect acne?
increases glucocorticoid secretion → suppresses immune system → can’t fight bacteria as well
pathogenesis of acne
pooling of sebum creates anaerobic conditions → proliferate propionibacterium acnes
T cell response → inflammation
lipase from bacteria hydrolyze TG into FFA → inc keratinization and microcomdeone formation → block pore
cytokine production and chemokine generate pus
What is noninflammatory acne?
open and close comedones
what is inflammatory acne?
papulopustular / nodular lesions (more severe)
how long after initiation of systemic corticosteroids might acne appear?
2-6 weeks
(removal leads to initial worsening due to inc inflammation)
What drugs may induce acne?
systemic corticosteroids, antiepileptics, tuberculostatics, lithium
What is the critical target for tx of acne?
microcomedone → eliminating follicular occlusion arrests cascade
what kind of therapy would you use for mild-moderate acne?
topical therapy
what kind of therapy would you use for moderate-severe acne?
systemic therapy
Why are soaps not always the best products to tx acne?
once rinsed off no further active product remains
high pH may degrade some ctivitiy of other agents and may be less tolerable on skin
What are disadvantages to topical therapy?
only works where its applied (not ideal for large areas) and most cause skin irritation
What is the mechanism of benzoyl peroxide?
penetrates stratum corneum unchanged and then is converted to benzoic acid which has activity against P. acnes
has peeling and comedolytic effects
What are adverse reactions of benzoyl peroxide?
can bleach hair, clothes, skin/mucous membrane irritation
How should benzoyl peroxide be prescribed?
start at a low concentration (2.5%) once daily then inc strength and frequency as tolerated
What is azelaic acid (azelex)?
straight chain dicarboxylic acid; topical tx for acne
start once daily then inc to twice daily
What is the mechanism of azelaic acid (azelex)?
not fully understood but likely due to antimicrobial activity and inhibiting conversion of testosterone to dihydrotestosterone
What are adverse rxns of azelaic acid (azelex)?
mild skin irritation / dryness and hypopigmentation
improves over 6-8 weeks w/ continuous therapy
What is retinoic acid (Retin-A)?
aka tretinoin; acid form of vitamin A
topical tx for acne, wrinkles, and dyspigmentation (first line for noninflammatory; can be combined w/ other agents for inflammatory)
What is the mechanism of tretinoin?
not completely understood but corrects abnormal follicular keratinization, reduces P. acnes counts, and reduces inflammation
What is the first line therapy for noninflammatory (comedonal) acne?
retinoic acid / tretinoin
What are adverse effects of topical retinoids?
erythema, desquamation, burning/stinging → decreases w/ time and use of emollients
photosensitivity and severe sunburn
avoid during pregnancy (fat soluble vitamin)
What 2 things are important to educate pt on when prescribing Tretinoin?
photolabile - apply at night
benzyl peroxide inactivates tretinoin
What is Adapalene (Differin)?
topical retinoid that’s stable in sunlight and w/ benzoyl peroxide
tends to be less irritating
What is Tazarotene (Tazorac)?
3rd gen retinoid used for acne and psoriasis
sometimes combined w/ topical steroids to reduce skin irritation
What topical retinoid is used in Kaposi sarcoma?
Alitretinoin (Panretin)
What topical retinoid is used in T-cell lymphoma?
Bexarotene (Targretin)
What are examples of topical abx for acne?
Clindamycin (Cleocin-t) and Erythromycin (Eryderm)
(lacks systemic SE but losing efficacy over time due to P. acnes resistance)
What is Isotretinoin?
systemic retinoid tx for acne that effective in 1-3 mos
very strong, severe teratogenicity- has iPledge program committed to pregnancy prevention
What is Isotretinoin contraindicated in?
pregnancy / breast feeding; men should avoid as well
What are adverse reactions to Isotretinoin?
retinoid dermatitis → erythema, pruritus, scaling
photophobia
arthralgia, HA, alopecia, brittle nails
inc serum lipids
monitor for signs of developing depression
What are examples of systemic abx used to treat more extensive acne?
Tetracylines, trimethoprim / sulfacetamide (bactrim), azithromycin (Zithromax), ciprofloxacin (cipro)
Which systemic abx are most commonly used when tx acne?
tetracylines- doxycycline, minocycline
What is salicyclic acid?
tx for acne but not great evidence to support use
keratinolytic
mild anti-inflammatory / anti-microbial activity
What is spironolactone (aldactone)?
antiandrogen used to tx acne by dec testosterone activity
available in a gel
What oral contraceptives are used to tx acne?
ethinyl estradiol and norethindrone / ethinyl estradiol
Intralesional steroid tx for acne
effective for individual inflammatory nodules
systemic absorption can occur causing adrenal suppression; can also cause local tissue atrophy
Oral corticosteroid therapy for acne
low dose can reduce sx in adrenal hyperactivity
short course may be beneficial in highly inflammatory dz
what is tx for type I acne?
topical retinoid is drug of choice; can also consider benzoyl peroxide or salicylic acid
what do you prescribe next if type I acne tx fails?
topical retinoid plus benzoyl peroxide, topical, or abx
what do you prescribe next if type II acne tx fails?
systemic abx plus topical retinoid or benzoyl peroxide
What do you prescribe next if type III acne tx fails?
add oral contraceptive or anti androgen (women only) then oral isotretinoin if that fails
What is the tx for type IV acne?
systemic abx plus topical retinoid, and benzoyl peroxide ± oral contraceptive or anti androgen
consider oral isotretinoin if not responding
what are major indicators of atopic dermatitis?
pruritus, rash in typical areas, chronic or repeated sx, family history
What are minor indicators of atopic dermatitis?
dry & patchy scales, inc serum IgE, positive allergy skin tests, susceptibility to skin infx
what are the goals of tx for atopic dermatitis?
provide sx relief
identify and eliminate triggers
minimize/prevent adverse rxns to tx
tx secondary skin infx
What is the gold standard therapy for atopic dermatitis?
topical corticosteroids
Why strength of steroids is better for long term therapy?
low potency- suitable for face, intertriginous areas, infants
What strength steroid is used for the body?
medium potency
What strength steroids are used for exacerbations of atopic dermatitis?
medium- high potency; use for 1-2 wks then switch to lower potency
What are local adverse effects of topical steroids?
skin atrophy, acne, rosacea, allergic dermatitis (related to vehicle)
what are systemic adverse effects of topical steroids?
adrenal suppression, infx, hyperglycemia, glaucoma, cataracts, growth retardation
what is the least potent steroid?
hydrocortisone
What 4 things can affect steroid potency?
the drug itself
strength/concentration
salt form of drug
dosage form (occlusiveness)
What are examples of topical immunomodulators?
Tacrolimus ointment (Protopic)
Pimecrolimus cream (Elidel)
What is the mechanism of topical immunomodulators?
inhibit activation of T cells, mast cells, and keratinocytes
What is second line after topical steroid tx for atopic dermatitis?
topical immunomodulators
What are adverse rxns of topical immunomodulators?
burning sensation, possible cancer risk, avoid w/ weakened immune system, use high SPF sunscreen
What are examples of oral corticosteroids?
prednisone (deltasone), dexamethasone (decadron), methylprednisolone (medrol dose pack)
What is sometimes used for short courses during atopic dermatitis exacerbations?
oral corticosteroids - provides rapid relief but needs tapering dose to prevent flare up
what is topical Bacitracin?
peptide abx that prevents cell wall synthesis, has broad antimicrobial coverage, and can be used alone or in combo w/ neomycin and polymyxin B
What are adverse effects of bacitracin ointment?
allergic dermatitis (rare)
no systemic toxicitiy
What is mechanism of Mupirocin (Bactroban)?
binds to bacterial t-RNA preventing protein synthesis
covers most gram positive aerobes (esp. MRSA) and used to eliminate nasal carriage of S. aureus
What are SE of Mupirocin (Bactroban)?
not absorbed but may cause mucous membrane irritation
What is polymyxin B?
peptide abx that interrupts cytoplasmic membrane
effective against gram negative organisms (pseudomonas, E. coli, klebsiella)
What are adverse effects of polymyxin B?
risk for neuro/nephrotoxicity- avoid using on open wounds / denuded skin in high doses
What are examples of aminoglycosides?
neomycin and gentamicin
What is mechanism of aminoglycosides?
inhibit bacterial protein synthesis
good activity against gram neg organisms
can have systemic accumulation
Which aminoglycoside frequently causes sensitization?
neomycin
What is the mechanism of azole antifungals?
inhibits fungal P450 preventing cell wall formation
Azole antifungals
used for topical and vaginal uses
sometimes combined w/ corticosteroids for more rapid sx relief
tx generally prolonged (2-3 wks)
What is mechanism for ciclopirox (penlac)?
inhibit uptake molecular precursors at fungal cell wall
What is ciclopirox (penlac) typically used for?
dermatomycosis, candidiasis, tinea versicolor, nail lacquer for onychomycosis
What are allylamines?
Naftifine and Terbinafine (Lamisil)
antifungals that inhibits production of ergosterol and prevents cell wall synthesis
What is Tolnaftate (Tinactin)?
anti fungal that is well tolerated but must be used for long term to prevent recurrence
no candida activity
What is nystatin?
used for candidal infx (cutaneous and mucosal)
no oral absorption
What is acyclovir (Zovirax) and Penciclovir (Denavir)?
synthetic guanine analogs that are active against HSV
used for recurrent orolabial HSV infection
What is Imiquimod (Aldara)?
anti viral used for external and perianal warts, AKs, and BCC
applied 2-5 times per week
What is the mechanism of Imiquimod (Aldara)?
immunomodulator that stimulates peripheral mononuclear cells to release interferon-a and stimulates macrophages to produce TNF a and interleukins
What are adverse rxns in Imiquimod (Aldara)?
skin irritation in virtually all pts → edema, vesicles, erosions, ulcers ; degree of inflammation parallels efficacy
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Flashcard (105)