Acne vulgaris
Basic Dermatology Curriculum
Last updated January 2015
Module Instructions
The following module contains a number of blue,
underlined terms which are hyperlinked to the
dermatology glossary, an illustrated interactive guide to
clinical dermatology and dermatopathology.
We encourage the learner to read all the hyperlinked
information.
Goals and Objectives
The purpose of this module is to help medical students develop a
clinical approach to the evaluation and initial management of
patients presenting with acne and rosacea.
By completing this module, the learner will be able to:
Identify and describe the morphology of acne vulgaris
Explain the basic principles of treatment for acne vulgaris
Recommend an initial treatment plan for a patient presenting
with comedonal and/or inflammatory acne vulgaris
Practice providing patient education on topical and systemic
acne treatment
Differentiate acne vulgaris from acne rosacea
Determine when to refer a patient with acne to a dermatologist
Acne Vulgaris: Epidemiology
Acne vulgaris, often referred to as acne, is a disorder of
pilosebaceous follicles
Epidemiology
Affects 90% of adolescents
All races equally affected
Family history is often positive
Typically presents at ages 8-12 (often the first sign of
puberty), peaks at ages 15-18, and resolves by age 25
12% of women and 3% of men will have acne until their 40s
In women, it is not uncommon to have a first outbreak at 2035 years of age
Acne Vulgaris: Clinical Presentation
Distribution
Acne affects mainly the face, neck, upper trunk and upper
arms (where sebaceous glands are abundant)
Morphology
Acne begins with clogged pores (pore = pilosebaceous
unit), aka comedones
Open comedones = blackheads
Closed comedones = whiteheads
Acne Vulgaris: Pathogenesis
Pathogenesis
Four factors are involved in the formation of acne lesions
Increase in sebum production (influenced by androgens)
Keratin and sebum plug the hair follicle and accumulate leading
to hyperkeratosis (comedone formation)
P. acnes (bacteria) proliferates in the sebaceous follicle
(releases enzymes and stimulates release of pro-inflammatory
cytokines)
Inflammatory response
Case One
Jim Reynolds
Case One: History
HPI: Jim Reynolds is an 17-year-old healthy teenager who presents
to his primary care physician with pimples on his face for the last 2
years. He reports a daily skin regimen of aggressive facial
cleansing with a bar soap during his morning shower.
PMH: no chronic illnesses or prior hospitalizations
Allergies: no known allergies
Medications: none
Family history: father and mother had acne as teenagers
Social history: lives at home with parents, attends high school
ROS: negative
Case One, Question 1
How would you describe Jims
skin exam?
a. Mild comedonal acne without
presence of scarring
b. Mild inflammatory acne
without comedones
c. Moderate mixed comedonal
and inflammatory acne with
presence of scarring
d. Moderate mixed comedonal
and inflammatory acne
without presence of scarring
Case One, Question 1
Answer: C
Moderate mixed comedonal
and inflammatory acne with
presence of scarring
Open comedo
Closed comedo
Pustule
Inflamed papule
Scarring
10
Classification of Acne Vulgaris
Classification of acne is based on the morphology
Comedonal: open and closed comedones
Inflammatory: papules and pustules
Nodulocystic: nodules and cysts
It is equally important to describe the severity and the
presence of scarring for each patient
Each type can be mild to severe depending on the extent and
density of acne
11
Case One, Question 3
Which of the following treatments would you recommend
for Jim?
a. Salicylic acid 2% facial wash
b. Tetracycline Oral antibiotic
c. Combination therapy with benzoyl peroxide and topical
retinoid cream
d. Combination therapy of oral isotretinoin and hormone
therapy
e. No treatment necessary at this time
12
Case One, Question 3
Answer: c
Which of the following treatments would you recommend for Jim?
a. Salicylic acid 2% facial wash (less effective than BP, combination
therapy indicated for moderate acne)
b. Tetracycline oral antibiotic (oral antibiotic monotherapy is not
recommended due to possibility of bacterial resistance)
c. Combination therapy with benzoyl peroxide and topical
retinoid cream (topical antibiotic could also be added)
d. Combination therapy of oral isotretinoin and hormone therapy
(these are used in refractory cases of moderate/severe acne,
not first-line)
e. No treatment necessary at this time (treatment of his acne is
important in order to prevent scarring)
13
Acne-Related Changes
Cystic or scarring acne should be treated
aggressively to prevent permanent
sequelae
Refer patients with difficult to control
acne or the presence of scarring to
dermatology
In addition to scarring, patients may
develop post-inflammatory
hyperpigmentation (hyperpigmented
macules that persist following
inflammation in the skin)
14
Topical Retinoids
(tretinoin, all trans retinoic acid)
Mechanism:
Topical retinoids are vitamin A derivatives that act by
normalizing the desquamation of follicular epithelium to
prevent formation of new comedones and promote the
clearing of existing comedones
Common Adverse Effects:
Dryness, pruritus, erythema, scaling, photosensitivity
Available forms:
Tretinoin, Adapalene, Tazarotene
Cream, gel, lotion, solution
15
Topical Retinoids
(tretinoin, all trans retinoic acid)
Additional considerations:
Use sunscreen and protective clothing to reduce photosensitivity
Do not apply at the same time as benzoyl peroxide because
benzoyl peroxide oxidizes tretinoin
Tretinoin and Adapalene are FDA Pregnancy Category C; other
agents are preferred for treatment of acne in pregnancy
Tazarotene is Category X and contraindicated in pregnancy
16
Benzoyl Peroxide
Mechanism:
Benzoyl peroxide is a topical medication with both antibacterial and
comedolytic properties
Acts via the generation of free radicals that oxidize proteins in the P
acnes cell wall
Available forms:
Available as a prescription and over-the-counter, as well as in
combinations with topical antibiotics
Cream, lotion, gel, or wash
Common Adverse Effects:
Bleaching of hair, colored fabric, or carpet
May irritate skin; discontinue if severe
17
Topical Antibiotics
Mechanism
Reduce the number of P. acnes and reduce inflammation in
inflammatory acne
Available forms:
Erythromycin 2% (solution, gel)
Clindamycin 1% (lotion, solution, gel, foam)
Common Adverse Effects:
Topical acne treatments are often irritating and can cause dry skin
When using retinoids or benzoyl peroxide, consider beginning on
alternate days
Use a moisturizer to reduce their irritancy
Additional considerations:
Often used with benzoyl peroxide (versus monotherapy) to prevent
the development of antibiotic resistance in the treatment of mild-tomoderate acne
18
Acne Treatment:
Patient education
Patient education and setting expectations are important
components of effective acne treatment
Physician and patient should develop a therapeutic regimen
with the highest likelihood of adherence
Acne treatment targets new lesions, not present ones
Lack of adherence is the most common cause of treatment
failure
Patients will often stop their topical treatments too early without
improvement in their acne
Topical agents take 2-3 months to see effect
Therapy should be continued for at least 8 weeks before a
treatment response can be accurately evaluated
19
Acne Treatment:
Patient education
Many patients can be non-adherent to topical treatments due to
adverse effects including skin dryness, peeling, redness,
itching, burning, and stinging
Acne-affected skin can be deficient in ceramides, which play an
important role in maintaining the skin barrier and preserving its ability to
prevent moisture loss
Daily use of ceramide-containing moisturizers may improve skin
dryness and irritation by repairing and maintaining the skin barrier,
leading to improved adherence
20
Acne Treatment:
Patient education
Patients should use only the prescribed medications and avoid
potentially drying over-the-counter products, such as astringents,
harsh cleansers or antibacterial soaps, as they are ineffective for acne
and potentially drying
Overaggressive washing and the use of particulate abrasive scrubs
often exacerbates acne and should be avoided
Cosmetics are often labeled as non-comedogenic or oil-free if
they do not cause or exacerbate acne
There is some evidence to suggest that diet contributes to acne
Low glycemic load diets may improve acne by reducing androgeninduced sebaceous gland activity and keratinocyte growth associated
with increased insulin and IGF-1 levels
21
Case Two
Ryan Townsend
22
Case Two: History
HPI: Ryan Townsend is a 15-year-old healthy teenager who
presents to his primary care physician for evaluation of
progressively worsening acne over the last 3 years
PMH: no chronic illnesses or prior hospitalizations
PSHx: Torn right achilles tendon 1 year ago
Allergies: no known allergies
Medications: OTC 10% Benzoyl Peroxide Wash and topical
retinoid
Family history: Older brother had acne as a teenager
Social history: lives at home with parents, attends high school
ROS: negative
23
Case Two: Physical Exam
How would you
describe Ryans skin?
24
Case Two: Physical Exam
Severe nodulocystic
acne with presence of
scarring
25
Case Two: Management
Ryan has used a combination therapy of 5% benzoyl peroxide and a
topical retinoid for the past year without significant improvement. What
other treatment strategies can you consider?
a.
b.
c.
d.
e.
Add a topical antibiotic
Add an oral antibiotic
Add oral isotretinoin
Refer to a dermatologist
All of the Above
26
Case Two: Management
Ryan has used a combination therapy of 5% benzoyl peroxide and a
topical retinoid for the past year without significant improvement. What
other treatment strategies can you consider?
a.
b.
c.
d.
e.
Add a topical antibiotic
Add an oral antibiotic
Add oral isotretinoin
Refer to a dermatologist
All of the Above
Severe acne can require combination therapy with oral antibiotics,
topical retinoids, benzoyl peroxide, +/- topical antibiotics
Dermatology referral for treatment with oral isotretinoin is necessary
in acne failing other therapies
Hormonal therapy in pubertal females can also be considered
27
Back to Case Two
You decide to prescribe Ryan an oral antibiotic, Minocycline 100 mg
PO BID.
Which set of side effects do you want Ryan to be aware of?
a. Depressive symptoms or mood changes
b. Dizziness, ataxia, nausea and vomiting
c. GI upset and photosensitivity
d. Xerosis, cheilitis, elevated liver enzymes, hypertriglyceridemia
28
Back to Case Two
Answer: B
Which set of side effects do you want Ryan to be aware of?
a. Depressive symptoms or mood changes (small number of
reported cases with Isotretinoin use, no strong evidence)
b. Dizziness, ataxia, nausea and vomiting
c. GI upset and photosensitivity (can be seen with any of the
tetracycline antibiotics)
d. Xerosis, cheilitis, elevated liver enzymes, hypertriglyceridemia
(known side effects associated with Isotretinoin)
29
Oral Antibiotics
Mechanism:
Reduce P. acnes colonization of the skin and follicles
Applications:
Moderate to severe inflammatory acne
Available forms:
Tetracycline, doxycycline, minocycline, among others
Often combined with benzoyl peroxide to prevent antibiotic resistance
Adverse effects:
GI upset (epigastric burning, nausea, vomiting and diarrhea can occur)
Photosensitivity (patients may burn easier, which can be easily
managed with better sun protection)
Sun block with UVA coverage is recommended for all acne
patients on tetracyclines
Minocycline can cause vertigo, dizziness, and hyperpigmentation
30
Oral Tetracyclines:
Patient Counseling
Additional considerations:
Contraindicated in pregnancy and in children <8 years old
If the patient has not responded after 3 months of therapy with an oral
antibiotic, consider:
Increasing the dose (if not at max dose)
Changing the treatment, or
Referring to a dermatologist
Patients need clear instructions
If taking for acne, it is okay to take antibiotics with food and dairy
products for tolerability of GI side effects
Take with full glass of water; prevents esophageal erosions
Tetracyclines do NOT interfere with birth control pills
It takes 2-3 months to see improvement
31
Minocycline pigmentation
Timing:
Pigmentation appears after months to years
in a small percentage of patients
Distribution:
First noticeable on the alveolar ridge,
palate, sclera
Morphology:
Skin deposition can be brown or blue-grey
(blue-grey pigmentation may occur in
scars)
Additional Considerations:
Skin pigmentation may not fade after
discontinuation
Patients on long-term minocycline should
be screened; if seen on gums or sclerae,
discontinue
32
Oral Isotretinoin
Mechanism:
Oral isotretinoin is a retinoic acid derivative that targets all four of the
pathophysiologic factors involved in acne
Applications:
Severe, nodulocystic acne failing other therapies
Typically given in a single 5-6 month course
Common Adverse Effects:
Xerosis (dry skin), cheilitis (chapped lips), elevated liver enzymes,
hypertriglyceridemia
Additional Considerations:
Isotretinoin is teratogenic and therefore absolutely contraindicated in
pregnancy
Female patients must be enrolled in a FDA-mandated iPLEDGE
prescribing program in order to use this medication
Female patients must use two forms of contraception during isotretinoin
therapy and for one month after treatment has ended
33
Review: Common First-Line Treatments
Acne subtype
Management
Initial: Topical retinoid or benzoyl peroxide (BP)
Alternative: Combination therapy of BP with topical
few inflammatory lesions
retinoid and/or topical antibiotic
Moderate Acne: Comedones Initial: Combination therapy with topical retinoid and BP
+/- topical Antibiotic
with marked number of
Inadequate response: Consider oral antibiotics,
inflammatory lesions
dermatology referral, and hormonal therapy for females
Initial: Combination therapy with oral antibiotic, topical
Severe Acne: Extensive
retinoid, and BP +/- topical antibiotic
Inflammatory Lesions with
Inadequate response: Consider oral isotretinoin,
diffuse scaring
dermatology referral, and hormonal therapy for females
Mild Acne: Comedones with
34
Mini Case
Billy
35
Mini Case: History
A mother calls the advice
line at your primary care
practice, and she is
concerned that her 5-yearold son, Billy, has acne.
She says he has pimples
and white heads and red
marks on his cheeks.
36
Mini Case: History
Which of the following signs would make you most
concerned about an underlying systemic abnormality?
(Mark All That Apply)
[ ] Breast Development
[ ] Craniofacial deformities
[ ] Facial Hair
[ ] Fever
[ ] Food Allergies
[ ] Itching
[ ] Increased Muscle Mass
[ ] Pubic Hair
[ ] Testicular Growth
[ ] Wheezing
37
Mini Case: History
Acne between the ages of 1 and 7 years-of-age is called Midchildhood acne, and it is very rare.
These features are all possible sequelae of excess androgens that
warrant workup by a pediatric endocrinologist.
Possible causes include: adrenal tumors, gonadal tumors,
congenital adrenal hyperplasia, Cushing syndrome, and precocious
puberty.
[x] Breast Development
[ ] Craniofacial deformities
[x] Facial Hair
[ ] Fever
[ ] Food Allergies
[ ] Itching
[x] Increased Muscle Mass
[x] Pubic Hair
[x] Testicular Growth
[ ] Wheezing
38
Mini Case: Pediatric acne
Pediatric acne can be categorized by the patients age and
pubertal status:
Neonatal acne (Onset birth to 6 weeks)
Usually self-limited; not true acne, no comedones
Infantile acne (Onset 6 weeks to 1 year)
Usually self-limited; true acne with comedones
Mid-childhood acne (1 year to 7 years)
Very uncommon
Preadolescent acne (7-12 years or menarche in girls)
Common
Adolescent acne (12-19 years or after menarche in girls)
Common
39
Mini Case: Pediatric acne
Treatment of pediatric acne
From 1 to 7 years, the primary objective is to rule out an underlying
systemic abnormality
The treatment of preadolescent acne is similar to that in older age
groups EXCEPT:
Oral tetracyclines are not used in children younger than 8 years of
age because of a risk of damage to tooth enamel and developing
bones
A topical retinoid can be started at any age but is off label in some
cases
Adapalene and benzoyl peroxide gel 0.1%/2.5% is FDA approved for children 9
and older
Tretinoin 0.05% gel is FDA approved from children 10 and older
Oral contraceptives for acne unassociated with endocrine
abnormalities should be withheld until 1 year after menarche
40
Case Three
Ms. Emily Garcia
41
Case Three: History
HPI: Ms. Garcia is a 22-year-old woman who was referred to
the dermatology clinic for new onset acne
PMH: no major illness or hospitalizations, no pregnancies
Allergies: allergic to penicillin (rash)
Medications: occasional multivitamin
Family history: noncontributory
Social history: lives in the city and attends college
Health-related behaviors: gained 40 pounds over the past 4
years despite a healthy diet and exercise habits
ROS: new upper lip and chin hair growth, irregular menstrual
cycles since menarche, last period was 4 months ago
42
Case Three: Skin Exam
How would you describe Ms.
Garcias skin?
43
Case Three: Skin Exam
Moderate comedonal and
inflammatory acne of cheeks
and jaw line, with scattered
terminal hairs on the upper lip
and lower chin
Hair loss noted
on frontal and
parietal scalp
44
Case Three, Question 1
Based on the history and exam, what is the most likely
diagnosis?
a. Cushing Syndrome
b. Gram negative folliculitis
c. Polycystic ovarian syndrome
d. S. aureus folliculitis
45
Case Three, Question 1
Answer: c
Based on the history and exam, what is the most likely
diagnosis?
a. Cushing Syndrome (manifestations of excessive
corticosteroids, which results in central obesity, muscle
wasting, thin skin, hirsutism, purple striae)
b. Gram negative folliculitis (multiple tiny yellow pustules
develop on top of acne vulgaris as a result of long-term
antibiotic administration)
c. Polycystic ovarian syndrome
d. S. aureus folliculitis (multiple follicular pustules and
papules)
46
Polycystic Ovarian Syndrome
Ms Garcia most likely has polycystic ovarian syndrome (PCOS)
Affected individuals must have two out of the following three
criteria:
(1) oligo- and/or anovulation,
(2) hyperandrogenism (clinical and/or biochemical)
(3) polycystic ovaries on sonographic examination*
In addition to hormonal acne, increased circulating androgens
also results in hirsutism
Women with PCOS also have a greater degree with insulin
resistance which can cause acanthosis nigricans
* Based on definition from the Rotterdam ESHRE/ASRM-Sponsored
PCOS Consensus Workshop Group, 2004
47
Case Three, Question 1
Ms. Garcia was given spironolactone and her acne
improved. Why did this medication work?
a. Spironolactone has anti-androgenic effects
b. Spironolactone has anti-comedonal activity
c. Spironolactone when used appropriately has antibacterial activity
d. The diuretic effect of spironolactone eliminated
sodium resulting in less sebum
48
Case Three, Question 1
Answer: a
Ms Garcia was given spironolactone and her acne
resolved. Why did this medication work?
a. Spironolactone has anti-androgenic effects
b. Spironolactone has anti-comedonal activity (not
true)
c. Spironolactone when used appropriately has antibacterial activity (not true)
d. The diuretic effect of spironolactone eliminated
sodium resulting in less sebum (not true)
49
Androgens in Acne
In many post-adolescent women,
antiandrogen therapy can improve acne
These women have hormonal acne;
their serum hormone levels are usually
normal
Hormonal acne lesions are often
perioral and along the jaw line
Many women report a pre-menstrual
flare
Not all women with hormonal acne are
tested for hyperandrogenism
It should, however, be considered in
the female patient whose acne is
severe, sudden in onset, or associated
with hirsutism or irregular menses
50
Treatment of Hormonal Acne
Commonly used agents to treat hormonal acne include:
Spironolactone (50 mg daily to 100 mg twice a day)
Mechanism: androgen-receptor blocker, inhibitor of 5-alpha reductase
Side effects: Diuresis, hyperkalemia, irregular menstrual periods,
feminization of a male fetus during pregnancy
Additional consideration: Combination with OCP can reduce irregular
periods
Oral contraceptives
Mechanism: suppress LH production, increase sex hormone binding
globulin, inhibit 5-alpha reductase, block androgen receptor
Available forms: Yaz, Ortho Tri-cyclen, Estrostep are FDA approved for
treatment of acne
Side effects: nausea, vomiting, abnormal menses, weight gain, breast
tenderness, increased risk of thromboembolism
51
Acne Rosacea
Acne Rosacea may look very similar to Acne vulgaris, however,
it can be differentiated by an absence of comedones
Morphology:
May present with easy flushing, erythema,
telangiectasias, papules and pustules, and/or
phymatous changes
Triggers:
Alcohol, sunlight, hot beverages (heat), spicy food,
emotional stress
Unlike acne vulgaris, it is not related to hormones
Additional Considerations:
Many patients with rosacea have ocular involvement
Treatment:
Topical and oral treatments often improve the papules
and pustules of rosacea, but will not reverse the
underlying erythema and flushing
All patients with rosacea should use sunscreen and
avoid known triggers
52
Periorificial Dermatitis
Periorificial dermatitis, also known as perioral dermatitis, is
another acneiform eruption that can be differentiated from
acne vulgaris by an absence of comedones
Morphology:
Erythematous papules and pustules with scaling
Usually located around the mouth, nose, and eyes
(occasionally involves the chin, cheek, or forehead)
Clinical features:
Child with periorifical dermatitis
Occasionally presents with pruritus or burning
Most patients will have history of prior or current
use of topical steroids (rash will often improve with
topical steroids and flare with cessation)
Treatment:
Gradually taper use of topical steroids
Systemic treatments: oral tetracycline for patients
8 years and oral erythromycin for patients < 8 years
Topical treatments: metronidazole, erythromycin,
and pimecrolimus
Adult with periorificial dermatitis
53
Take Home Points: Acne Vulgaris
Morphology:
Characterized by open and closed comedones, papules,
pustules, nodules, and cysts
Severity and presence of scarring must be included when
describing acne
Pathogenesis:
Related to the presence of androgens, excess sebum
production, the activity of P. acnes, and follicular
hyperkeratinization
Treatment:
Systemic and topical retinoids, topical benzoyl peroxide,
systemic and topical antimicrobials, and systemic hormonal
therapies are the main classes of treatment for acne vulgaris
Untreated acne can result in permanent scarring
54
Acne Vulgaris Review:
Common First-Line Treatments
Acne subtype
Management
Mild Acne
Initial: Topical retinoid or benzoyl peroxide (BP)
Alternative: Combination therapy of BP + topical retinoid
and/or topical antibiotic
Initial: Combination therapy with topical retinoid and BP
+/- topical Antibiotic
Inadequate response: Consider oral antibiotics,
dermatology referral, and hormonal therapy for females
Initial: Combination therapy with oral antibiotic, topical
retinoid, and BP +/- topical antibiotic
Inadequate response: Consider oral isotretinoin,
dermatology referral, and hormonal therapy for females
Moderate Acne
Severe Acne
55
Acknowledgements
This module was developed by the American Academy
of Dermatology Medical Student Core Curriculum
Workgroup from 2008-2012.
Primary authors: Sarah D. Cipriano, MD, MPH; Eric
Meinhardt, MD; Timothy G. Berger, MD, FAAD; Kanade
Shinkai, MD, PhD, FAAD.
Peer reviewers: Rebecca B. Luria, MD, FAAD; Cory A.
Dunnick, MD, FAAD; Renee Howard, MD, FAAD;
Rachel Kornik, MD, FAAD.
Revisions and editing: Sarah D. Cipriano, MD, MPH;
John Trinidad, Erin Mathes, MD; Matthew Dizon. Last
revised October 2014.
56
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To take the quiz, click on the following link:
https://www.aad.org/quiz/acne-and-rosacealearners
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