OS 212 [B]: Locomotion and Sensation - Dermatology
Lec 10: Dermatologic Therapeutics
March 19, 2014
Dr. Charissa Mia Salud-Gnilo
TOPIC OUTLINE
I. Successful Dermatologic Therapy
II. Cutaneous Drug Delivery
III. Host Factors Affecting Topical Therapy
A. Disaese
B. Site
C. Skin Integrity
D. Age & Pregnancy
IV. Drug Properties Affecting Topical Therapy
A. Potency
B. Occlusion
C. Vehicle
D. Amount
E. Frequency
F. Duration
G. Compounding
H. Adverse Effects
V. A successful dermatologic therapy (additional)
VI. Quiz (from 2017A)
1
 A variety of structures penetrate the stratum corneum and epidermis
and are potenstial SITES OF DISCONTINUITY OF THE SKIN
BARRIER. Hair follicles represent a resrvoir of topically applied
substances. Hair is most dense at the scalp, followed by the forehead
and the calf.
Legend:
From discussion, from PPT notes
“From 2016B” – 2016B
“From 2017A” – 2017A
Transers’ Note: Lecture content and structure are different from that
of 2017 Block A trans. Ma’am gave us a copy of the powerpoint and
we took pictures of slides. We re-organize the structure and edit and
add contents – basis is powerpoint and actual discussion.
Figure 2. Percutaneous absorption. Red arrows represent drug. Hair
follicle acts as a reservoir of drug and as a site of discontinuity of the skin.
I. SUCCESSFUL DERMATOLOGIC THERAPY
A. DISEASE




Assess accurately the type of eruption
Understand the principles of use of topical agents
Know the different dermatological vehicles and what they can do
Be acquainted with the structure and mode of action of some important
topical compounds
This lecture focuses on topical corticosteroids. Although, as dermatology
practitioners, we must be knowledgeable of non-topical drugs as well.
From 2016B: The vehicle is as important as the active drug itself.
II. CUTANEOUS DRUG DELIVERY
III. HOST FACTORS AFFECTING TOPICAL THERAPY
INDICATIONS FOR TOPICAL STEROIDS
 effective for:
o inflammation
o hyperproliferation – from 2017A: due to anti-mitotic activity
o immunologic involvement
 relieve
o burning
o pruritus – from 2017A: inhibition of histamine release, thus
inhibiting vasodilation and cytokine release
 Responsiveness of diseases to glucocorticoids varies.
o acute and inflammatory > chronic, hyperkeratotic and lichenified
  penetration –  drug responsiveness
Table 1. Responsiveness of various dermatoses to application of
topical corticosteroids.
HIGHLY
MODERATELY
LEAST
RESPONSIVE
RESPONSIVE
RESPONSIVE
palmoplantar
proriasis
psoriasis trunk
psoriasis
intertriginous
parapsoriasis
nail psoriasis
atopic dermatitis in
atopic dermatitis in
acute phase of
infants & children
adults
allergic contact
seborrheic
1o irritant dermatitis
dermatitis
dermatitis
nummular eczema
dyshidrotic eczema
lupus erythematosus
pemphigus
lichen planus
papular urticaria
granuloma annulare
intertrigo
lichen simplex
necrobiosis lipoidica
chronicus
diabeticorum (NLD)
sarcoidosis
insect bites
B. SITE
Figure 1. Histology: Layers of Skin (from lionden.com)
 Cutaneous drug delivery is affected by
 1.) Potency and 2.) ability to penetrate the skin (In order to be
absorb, the compound necessitate to penetrate some compartments of
the skin)
o Stratum corneum (20um thick; rate limiting barrier
o Epidermis (5x thicker than corneum)
o Dermis (has cutaneous vasculature at papillary dermis)
 Bloodstream
 3.) Inherent host and external factors
 In general, absorption of topical drugs is poor (only 1-2%) and require
a longer period of time. Peak rate of absorption is after 12-24 hrs after
application. For example only 2% of topical Hydrocortisone is absorbed
after 24 hrs. Drugs such as topical corticosteroids are effective
because of their inherent potency and can exert clinical significant
effect in spite of their low absorption.
Tangco, Turalde, Ty
 Different sites = different absorption rates
 Factors affecting variable percutaneous absorption:
1. Thickness (stratum corneum)
2. lipid composition
Figure 3. Regional Variation of Percutaneous Penetration
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OS 212
Lec 10: Dermatologic Therapeutics
  thickness of the stratum corneum   penetration  
responsiveness and local side effects
Table 2. Regional variation in percutaneous penetration of
hydrocortisone in man.
SITE
% ABS
SITE
% ABS
sole of the foot
back
0.14
1.7
ankle (bilateral)
scalp
0.42
3.5
palm
axilla
0.83
3.6
Forearm (ventral)
forehead
1
6
forearm (dorsal)
eyelid
1.1
42
C. SKIN INTEGRITY
 diseased skin – altered stratum corneum (/ penetration)


increase
penetration of topical meds
 Skin integrity affects BIOAVAILABILITY
 There is increased penetration in
o Inflamed diseased skin
o Hydrated skin
 In atopic dermatitis, the penetration is 2-10x greater than that
through healthy skin
D. AGE EXTREMES & PREGNANCY
PEDIATRIC CONSIDERATIONS
 More susceptible to the side effects of topical drugs due to :
o Greater skin surface area-to-body weight ratio (2.5-to 3x that of
adults)
o fragile skin
o decreased drug metabolism
o Use the lowest potency corticosteroid that is effective.
 Occlusive coverings may increase percutaneous absorption.
need for a less potent drug
PREGNANCY
fetal risk
categories A-C
IV. DRUG PROPERTIES AFFECTING TOPICAL THERAPY
A. POTENCY
 Describes the intensity of a topical corticosteroid’s clinical effect.
 From 2017A:  potency –  efficacy –  side effects; important to
approximate side effects with desired therapeutic effect
Table 5. WHO corticosteroid potency classification.
INCLUSION
HYDROCORTISONE
methylprednisolone, prednisolone
DESONIDE, TRIAMCINOLONE
clobetasone, hydrocortisone butyrate, hydrocortisone
buteprate, flumetasone, alclometasone,
BETAMETHASONE, FLUOCINOLONE ACETONIDE,
FLUOCORTOLONE, DIFLUCORTOLONE,
III
FLUOCINONIDE, MOMETASONE,
(potent)
METHYLPREDNISOLONE ACEPONATE
hydrocortisone aceponate
IV
CLOBETASOL
(very
halcinonide
potent)
CAT
I
(weak)
II
(mod.
potent)
From 2016B: memorize the drugs in all caps,
Dr. Salud-Gnilo did not mention anything about memorizing the ones in allcaps.
GERIATRIC CONSIDERATIONS
 Increased risk for side effects from topical corticosteroids
o thinness and fragility secondary to age-related skin atrophy.
 Similar precautions as with infants and children should be taken
From 2017A: Because of the reasons above, infants and the elderly (age
extremes) are more prone to the side effects of corticosteroid treatment.
As such, the lowest potency drug that is effective is used.
CONSIDERATIONS DURING PREGNANCY
 From 2017A:
o fetal risk should be minimal to none
o as much as possible, use category A and B drugs
o category C (used only after careful consideration the patient’s
case; risk-benefit assessment)
CAT
A
B
C
D
X
Table 3. FDA pregnancy categories for drugs.
INCLUSION
no fetal risk in controlled studies
no risk to human fetus despite possible animal risk OR
no risk in animal studies but human studies lacking
human risk cannot be ruled out
animal studies may or may not show risks
evidence of risk to human fetus
contraindicated in pregnancy
 some oral and topical drugs are excreted in breast milk
 no adverse effects on lactation from the use of topical
corticosteroids has been documented
 Application of topical drugs to the breasts should be done immediately
following nursing to allow as much time as possible before the next
feeding or not less than 2 hrs. to the next feeding.
Table 4. (From 2017A) Summary of Host Factors Affecting Topical
Therapy
DISEASE
Presentation
Site
acute, inflamed, abraded, eczematized, hydrated
 skin thickness
(-) lichenified
 hair follicles
 penetration
 drug responsiveness
 need for a more potent drug
AGE EXTREMES
 skin thickness
 penetration
 drug effect
 kidney, liver function
 elimination
 side effects
Tangco, Turalde, Ty
Figure 4. Topical Corticosteroids – Efficacy correlates with side
effects. The more potent the steroid, the greater the side effects
B. OCCLUSION








Occlusion can increase drug delivery from 10 to 100 times.
Immerse in water for 5 minutes
Apply airtight dressing (vinyl/cotton gloves, socks, plastic wrap)
E.g. Medication impregnated in an airtight dressing/tape ex.
Flurandrenolide –Cordran
Up to 10x increase in steroid penetration
Can be used in combination with all vehicles
Often used overnight
Watch out for: Irritation, folliculitis and infection
C. VEHICLE




serve as carrier for the active drug
adjunct for skin hydration
augmentation of drug penetration
Excipient (Vehicle) + Active Ingredient = DRUG
Table 6. Different vehicles.
PREP
COMP’N
MOISTURE
ointment
water in
oil
very
moisturizing
cream
oil in
water
mod.
moisturizing
gel
lotion
 immune
function
solution
cellulose
+
alcohol/
acetone
oil in
water +
alcohol
alcohol
drying
DERMATOSES
thick
lichenified
scaly
acute
subacute
weeping
SITE
COSMESIS
IRRITATION
palmar
plantar
very
greasy
low
moist,
intertriginous
occluded areas,
scalp, hair-dense,
mucosa
variable
elegant
elegant
high
If lesion is wet, dry it (cream – mod. moisturizing only). If it’s dry,
moisturize it (ointment).
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Lec 10: Dermatologic Therapeutics
D. AMOUNT
Figure 5. Fingertip Guide
for the Amount of Topical
Steroid.
One fingertip unit (FTU) –
distal IP joint to tip of finger
equivalent to 0.5g of steroid
From 2017A 1-3% body
surface area = 1 FTU = 1/2 g
steroid
Table 7. Fingertip unit requirements for adults.
BID (g)
BID (g)
BID (g)
AREA
FTU
APP’N, 7
APP’N, 4
APP’N
days
weeks
face and neck
2.5
2.5
17.5
70
anterior/posterior
7
7
49
196
trunk
arm
3
3
21
84
hand (both sides)
1
1
7
28
leg
6
6
42
168
foot
2
2
14
57
BID means ‘bis in die’ which is Latin for twice daily. The face and neck
requires 2.5 FTU (0.5g steroid/ftu) to cover the area per application,
meaning 1.25 g should be applied. Hence, 2.5 g per day is needed for
BID application, 7.5 g in 7 days, and 70 g in 4 weeks.
May also serve as guide to prescribing clinician on how many tubes of
medication to prescribe.
OS 212
 usually topical corticosteroid with:
o antibiotics
o antifungals
o salicylic acid
o tar
o urea
 There are drugs in the market which contain almost all of the above.
These should be avoided to prevent unwanted effects. Targeted
therapy is still better - ↓ side effects
H. ADVERSE EFFECTS
 Educating the public regarding the adverse effects of steroids is
essential. Some of these are irreversible.
 generally uncommon
 local > systemic
o striae (rubrae distensae) – irreversible
o atrophy – irreversible
o periorbital dermatitis – irreversible
o steroid acne – reversible; monomorphic (magkakamukha)
o easy bruisability
o systemic – Cushing’s (Tx: discontinue or taper, supplemental oral
steroids)
 critical – 50 g in a week will already have systemic side effects
 from 2017A; there could be HPA (hypothalamic-pituitary-adrenal) axis
suppression, especially if drug is more potent (e.g. clobetasol)
E. FREQUENCY
 usually 1-2x daily because absorption is 12-24 hours
 more frequently in:
o skin with thick stratum corneum (e.g. palms, soles)
o sites from which the medication is easily removed during normal
activity (e.g. hands – washing)
 DEPOT Effect
o Stratum corneum may act as a reservoir for TCS for up to 5 days.
o Retention is TCS concentration and formulation dependent.
o From 2017A:
 to lessen need for reapplication
 stored steroids for sustained release
 pilosebaceous unit – lipophilic drugs
 sweat glands – hydrophilic drugs
 “LESS IS MORE”
o Benefits of less frequent application:
 ↓ side effects and tachyphylaxis
 ↑ patient compliance
 ↓ cost of therapy
F. DURATION
 discontinue or taper potency when the skin lesion has resolved
 long term therapy may be used for chronic chronic skin disease that
is responding to treatment with the medication – watch out for
tachyphylaxis
 Every-other-day therapy or weekend-only (pulse therapy; e.g.
psoriasis treatment regimen wherein vit.b analog is given during
weekends and steroid during weekday) application for chronic
conditions
 limit to </= 3 weeks for superpotent drugs
 up to </= 3 months for midpotent drugs
 clinically, 2 week course then reassess
 if used >3 weeks, do not discontinue abruptly, taper to avoid rebound
and systemic side effects
G. COMPOUNDING
 combination of active drugs
 <1% prescriptions
 assess compatibility, stability and interaction of drugs
Tangco, Turalde, Ty
Figure 6. (first row L to R) Striae, Skin atrophy, easy bruisability
(second row L to R) perioral dermatitis, steroid acne
 dependent on:
o chemical nature / potency of the drug
o vehicle
o site
o patient population
o duration
 Treatment is PREVENTION
o Adverse effects are avoided by discontinuing or tapering
 there have been deaths from overzealous use of topical corticosteroids
 consider referral to endocrinologists





HPA AXIS SUPPRESSION: TREATMENT
withdraw the topical corticosteroid
reduce the frequency of application
substitute a less potent steroid
consider referral to endocrinologists
For S/Sx of glucocorticoid insufficiency:
o supplemental systemic corticosteroids
o tapering topical corticosteroids
V. A SUCCESSFUL DERMATOLOGIC THERAPY (ADDITIONAL)




Assess accurately the type of eruption
Understand the principles of use of topical agents
Know the different dermatological vehicles and what they can do
Be acquainted with the structure and mode of action of some important
topical compounds
 The aspects mentioned above comprise a successful dermatologic
therapy. However, those are not complete and holistic. A practitioner
must also consider the aspect of ACCESS. Access entails:
o 1) Rational selection
o 2) affordable prices
o 3) sustainable financing
o 4) reliable health and supply systems
 Dr. Gnilo’s sharing: The department is organizing a community
dermatology program at AMIGA (Alfonso, Mendez, Indang, Gen.
Aguinaldo, Amadeo) Municipalities of Cavite wherein residents go to
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Lec 10: Dermatologic Therapeutics
the community to man skin clinics. One of their colleagues assessed
the prevalent skin condition in AMIGA and the drugs available in the
locality. Prevalent conditions include: scabies, fungal, bacterial,
eczematous disease, contact dermatitis, acne and lice. No permethrin
(anti-scabies), terbinafines (for dermatophytes). There are sources for
mupirocin, oral antibiotics, and topical steroids. What their colleague
did was to search literature on alternative remedies for prevalent
conditions. The remedies are as follows: wheatfield ointment (for
tinea), azoles (for tinea), benzyl benzoate (for scabies). As for
sustainable financing, they urged AMIGA officials to buy dermatologic
therapeutics by bulk to lessen cost.
ESSENTIAL MEDICINES
 intended to be available within the context of functioning health
systems at all times,
 in adequate amounts,
 in the appropriate dosage forms,
 with assured quality, and
 at a price the individual and the community can afford.
OS 212
THIN ATROPHIC SKIN
From 2017A: low potency
From 2016B:low potency, do not occlude
DRY XEROTIC SKIN
VI. QUIZ (FROM 2017A)
Given the following skin conditions, what are the appropriate
dermatologic therapeutic agent and vehicle.
DRY LICHENIFIED SKIN
From 2017A: moderately potent cream (mildly moisturizing) compounded
with petroleum jelly (an ointment, hence moisturizing); lotion with
emollient (moisturizing)
From 2016B: moderate to high potency; combination, potent then shift
END OF TRANSCRIPTION
From 2017A: potent ointment (moisturizing) compounded with keratolytic
agents, occlude
From 2016B: moderately potent, occlude OR potent, taper to mid-potent
or decrease frequency; consider socioeconomic status (potency = price)
WET ECZEMATOUS SKIN
Wilson: Ginandahan, sinipagan, at binuhusan naming ng pagmamahal
ang trans na ito :D Nawa’y iboto n;yo kaming best transers sa 2017
Awards! Ang bumoto samin, may exclusive access sa event sa baba:
IMPORTANT ANNOUNCEMENT!
From 2017A: low potency using a drying vehicle (cream – mildly
hydrating, lotion/gel – irritating)
From 2016B: low potency drug like hydrocortisone cream; antibiotics
because to counter infectionz
THICK SCALY SKIN
From 2017A: potent ointment
From 2016B: psoriasis – potent ointment/lotion (water-based because
lesions are extensive), occlude, shift/taper to avoid adverse effect,
maintenance at low potency; more than one formulation for maximum
benefit
Tangco, Turalde, Ty
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