Transcript Pathophysiology of Acne

Treatment of
Acne
What is acne?
 Acne vulgaris: a chronic condition linked to the onset of
puberty
 Not a physical threat;
 However, acne may have a significant negative
psychological effect: low self esteem, social phobia and
depression;
 Universal incidence;
 85% of those between 15-24 years;
Anatomy and Physiology of skin
Pilosebaceous
unit=hair follicle +
sebaceous gland
Pilosebaceous Unit: most commonly on face, chest and back
Etiology of Acne
1. Abnormal keratinization of the
epithelial cells in the infindibulum
(duct);
2. An increase in sebum production;
3. An accelerated growth of
Propiobacterium acnes;
4. The occurrence of inflammation;
Pathophysiology of Acne
 Abnormal keratinization of the cells in the
infundibulum results in obstruction of the
follicle with impacted cells and sebum to
form a plug;
 This plug will distend the follicle and form
a microcomedone
 Microcomedone is the initial pathologic
lesion of acne
Microcomedone
Pathophysiology of Acne
 As more sebum accumulate, the
microcomedone enlarges and becomes visible
as a closed comedo, or white head
 The whitehead: is a small pale nodule just
beneath the skin surface that may form a
precursor for other acne lesions
 An open comedo (blackhead) occurs: when the
desquamated epithelial cells and sebum
accumulate behind the plug and the orifice of the
follicular canal becomes distended, allowing the
plug to protrude
 The tip of the plug may darken because of
melanin NOT dirt;
Closed comedone (whitehead)
Open comedo (blackhead)
Pathophysiology of Acne
 Increase in the level of circulating androgens
stimulates production of sebum, which is prevented
from reaching the skin surface by the obstructing
plug;
 At same time; P. acnes colonizes the
pilosebaceous duct;
 Bacterial colony counts are higher in patients with
acne than in those without acne
 P. acnes: major contributor to causing inflammatory
acne lesions lipase: breakdown of sebum to
highly irritating free fatty acids
 The resultant inflammation: localized tissue
destruction
Pathophysiology of Acne
 Inflammatory acne begins with closed
comedones that distend the follicle, causing the
cellular lining of the walls to spread and become
thin;
 Primary inflammation results from disruption of
the epithelial lining + lymphocyte infiltration
 A severe inflammatory reaction happens if the
follicle wall ruptures spontaneously or is
ruptured by picking, squeezing, or attempted
expression with a comedo extractor
Papules
Pustules
Pathophysiology of Acne
Contents are discharged into surrounding
tissue: abscesses scars or pits after
healing
Pits
Pustules or purulent nodules of
inflammatory acne are more likely to
cause scarring than those of noninflammatory acne
Exacerbating Factors for Acne
Several factors are known to exacerbate
existing acne or cause periodic flare-ups
of acne in some patients;
Some may have control over, while others
not (e.g. heredity);
Factors: environmental and physical,
cosmetic use, hormonal factors and
medication use
Environmental & Physical
1. Hydration: decreases size of duct orifice and
prevents loosening of comedone. e.g. high
humidity environment or prolonged sweating and
occlusive clothing
2. Irritation and friction (acne mechanica): may
increase symptoms of acne. E.g. occlusive
clothing, headbands, helmets, resting chin or
cheek on hand etc
3. Occupational acne: exposure to dirt, vaporized
cooking oils, or certain industrial chemicals
Cosmetic Use
 Acne cosmetica: mild form of acne on the face,
cheek and chin;
 Typically: closed, non-inflammatory comedones;
 Occurs as a result of using oil-based products
on the skin that causes occlusion of the
pilosebaceous unit;
 Oil-based cosmetics may exacerbate acne or
even induce it;
 Moisturizers or tanning oils may contain
comedogenic oils (e.g. lanolin, mineral oil, cocoa
butter)
Rosacea
Pomade acne
pustule
Comedo extractor
Pustules (purulent
nodules)
Emotional Factors
Severe or prolonged periods of stress may
exacerbate acne; however they do not
induce acne!
Mechanism is not known
Hormonal Factors
Many women with acne experience a
premenstrual flare-up of symptoms (i.e.
ovulation, pregnancy).
OCP with high androgenic progestin are
implicated in the production of acne
Medication Use
P
Phenytoin
I
Isoniazid
M
Moisturizers
P
Phenobarbital
L
Lithium
E
Ethionamide
S
Steroids
Unsubstantiated Etiologic Factors
Little evidence supports link between: diet
and acne;
A rule of thumb: people should be advised
to avoid any particular food that seems to
exacerbate their acne;
Excessive scrubbing in attempt to open
blocked pores may exacerbate rather than
improve acne
Signs and Symptoms of Acne
 Non-inflammatory acne is characterized by
whiteheads or blackheads
 Inflammatory acne is characterized by pimples
(i.e. small, prominent inflamed elevations of the
skin) which may rupture to form a papule
 Papules are inflammatory lesions appearing as
raised, reddened areas on the skin, which may
enlarge to form pustules
 Pustules appear as raised reddened areas filled
with pus
Papule
pimple
whiteheads
pustule
blackheads
Very severe acne, cystic acne,
acne conglobata
Classification of Acne
Grade
of
Acne
Qualitative
Description
Quantitative Description
I
Comedonal acne
Comedones only, < 10 on face, none on
trunk, no scars, noninflammatory lesions only
II
Papular acne
10-25 papules on face and trunk, mild
scarring, inflammatory lesions < 5 mm in
diameter
III
Pustular acne
More than 25 pustules, moderate scarring,
size similar to papules but with visible
purulent core
IV
Severe persistent
pustulocyctis
acne
Nodules or cysts, extensive scarring,
inflammatory lesions > 5 mm in diameter
-
Recalcitrant
severe cystic
acne
Extensive nodules/cysts
Treatment of Acne
Non-pharmacologic therapy
 Cleansing of Skin (avoid abrasive producs)
 Staying well-hydrated
 Minimizing Exacerbating factors
 Physical treatment with acrylate glue-based
strips (help in extraction of impacted
comedones) – better alternatives to picking acne
that may result in scarring)
Pharmacologic Therapy
Important points to
remember!
 Self-treatment of acne is effective in patients
mature enough to understand that acne can be
controlled but not cured;
 Treatment of noninflammatory acne:
pharmacologic agents + nonpharmacologic
measures;
 Self treatment is appropriate only for grade I
acne (i.e. noninflammatory acne of mild to
moderate severity), presenting with open or
closed comedones
Exclusion for Self-Treatment
Grades II-IV acne: papules, pustules,
nodules, cysts and/or scarring
Severe, recalcitrant acne (extensive
nodules/cysts)
Exacerbating factors (e.g. comedogenic
drugs)
Possible rosacea
(If acne lesions persist beyond mid-20s or develop in the
mid-20s or later, the symptoms may signal rosacea
rather than acne vulgaris)
Pustular - an oral antibiotic would be
best:
Comedonal acne - topical
treatment appropriate:
Severe acne treated with Isotretinoin:
A) Before treatment:
B) After 5 months
OTC Therapy
Benzoyl Peroxide
Salicylic acid
Sulfur
Sulfur-Resorcinol combination
products
Alpha-hydroxy acids
Benzoyl Peroxide
 Available in variety of concentrations (2.5%, 5%
& 10%) & dosage forms (lotions, gels, creams,
cleansers, masks & soaps);
 MOA: (1) irritation & desquamation-prevents
closure of pilosebaceous duct. Increase
turnover rate of epithelial cells. (2) Oxidizing
potential-antibacterial activity, decreasing
P.acnes
 Is frequently combined with topical antibiotics
(reduces the P. acnes resistance)
Benzoyl Peroxide
 The most effective and widely used OTC drug
for non-inflammatory acne;
 Clinical response to all concentrations is similar in
reducing the number of inflammatory lesions
 Should be applied to the entire affected area, &
not only to visible blemishes
 Should not be applied for 20 min. after washing
with a cleanser to minimize irritation
 Use only one application per day or every other
day
 Leave initial application for only 15 min., then
wash off
 If no discomfort, increase time the product is left
on the skin in 15 min. increments
 Once tolerated for 2 hours, leave on the skin
overnight
 After initial 1-2 weeks, application can be
increased to 2-3 TD over a period of 2-3 days,
as tolerated
 Fair skinned patients should apply 2.5% product
initially
 Max. effect may develop only after 4-6 weeks
 If necessary, strength may be increased to 5%
after 1 wk, then to 10% after 2 wks
Continue treatment even after clearance of
lesions
If no improvement after 6 wks or if ADRs,
seek medical attention,
Use carefully around nose, lips, eyes &
near cuts
Use other acne products only as indicated
Avoid sun & UV lamps, use sunscreens
with SPF > 15
Benzoyl Peroxide
Adverse Effects:
some skin sloughing, erythema or edema
lower concentrations must be used for
shorter duration
Allergic reactions – should be tested on
antecubital area
Precautions: (1) bleach hair, clothes, bed
linens, (2)avoid excessive sun or sunlamps,
Concern: tumorigenic potential
Salicylic Acid
 Available in wide range: 0.5%-2%
 A milder, less effective alternative for tretinoin
 MOA: acts as a surface keratolytic, mild
comedolytic agent
 Milder effect that tretynoin
 Is used as adjunctive treatment in cleansers
 Should not be used in DM & in poor circulation
 Use on large surface for long periods may result
in toxicity
 Needs sunscreen
 In case of irritation, limit to once daily use
Sulfur
Keratolytic and antibacterial (precipitated or
colloidal) 3%-10%
Generally: accepted as effective in
promoting the resolution of existing
comedones, but, on continued use, may
have a comedogenic effect
Alternative forms of sulfur: Na thiosulfate,
Zn sulfate, Zn sulfide NGRSE
Applied in thin film to skin 3 times daily
Have noticeable color and odor
Sulfur-Resorcinol combination
3-8% sulfur with resorcinol 2-3%
(enhances effect of sulfur)
MOA: keratolytics, fostering cell turnover &
desquamation
Resorcinol produces a reversible dark
brown scale on some darker-skinned
individuals
Sulfur-Sodium sulfacetamide
Combination destroys PABA, essential
component for bacterial growth
Alpha-hyrdoxy Acids
 They occur naturally in sugar cane, fruits & milk
products;
 Are keratolytic
 Less potent & are used when patient cannot
tolerate other topical products
 The most useful AHAs in dermatologic practice
are glycolic, lactic & citric acids
 MOA: facilitate desquamation of the stratum
corneum.
 No evidence to support use in acne – but may
be useful after acne control as peeling agents to
control scarring & hyperpigmentation
Therapeutic Comparison
Benzoyl Peroxide Salicylic Acid
Sulfur
Bactericidal
Yes
-
Yes
Keratolytic
Slight
Yes
Yes
-
Yes
Yes
Comedolytic
Concentration
2.5%-20%
0.5%-2%
2%-10%
Frequency of use 1-2 times daily
Used mainly as
cleanser, then
rinsed off
1-3 times daily
Adverse effects
Potent keratolytic
at high
concentration
Color, unpleasant
odor
Bleached hair and
clothing
CAM
Tea tree oil: comparative to benzoyl
peroxide but: slower onset
Oral zinc: may be used as alternative to
tetracycline esp. in summer
(photosensitivity). ADRs: nausea &
gastralgia
Nicotinamide: used in Europe for
inflammatory acne
Product Selection Guidelines
 Cleansers (bars, liquids) are not of much value
(WHY?)
 Gels are the most effective (WHY?)
 Gels & solutions cause drying - sometimes
contact dermatitis but are beneficial for oily skin
 Lotions & creams with low fat content are
intended to counteract drying (astringent effect)
and peeling (keratolytic effect): alternative to
more effective gels for dry sensitive skin or
during winter weather
 Ointments are greasy & may worsen acne
Patient Education:
 Acne is not caused by poor hygiene or eating
greasy or sugary foods
 Can be controlled by certain medications but not
cured
 The goal of self-treatment is to control mild acne,
thus preventing more serious form from
developing
 Best approach is use cleansers and medications
to keep skin ducts and orifices open
 Many OTC products are used with prescription
ones
Patient Education:
Cleanse skin thoroughly but gently at least
twice daily to produce a mild drying effect
that loosens comedones, using soft wash
cloth, warm water and facial soap without
moisturizing oils
To prevent or minimize acne flare-ups,
avoid or reduce exposure to environmental
factors, such as dirt, dust, petroleum
products, cooking oils or chemical irritants
Patient Education:
To prevent friction or irritation that may
cause acne flare-ups, do not wear tightfitting clothes, headbands, or helmets,
avoid resting the chin on the hand;
To minimize acne related to cosmetic use,
do not use oil based cosmetics and
shampoos
“I know you're never supposed to squeeze
a zit, but I'm not about to leave the house
with a major eruption on my face. Isn't
there any good way to pop it?”
!!!!!
Patient Education:
To prevent excessive hydration of the skin,
which can cause flare-ups, avoid areas of
high humidity and do not wear tight fitting
clothes that restrict air movement;
Avoid stressful situations & practice stress
management techniques. Stress may
worsen only existing acne.
Do not pick or squeeze pimples – may
worsen acne & lead to scarring