Blotches:
Light rashes
Basic Dermatology Curriculum
Last updated April 18, 2011
1
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.
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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 light rashes.
 After completing this module, the medical student will be
able to:
• Identify and describe the morphology of common light rashes
• Describe the use of Wood’s lamp and KOH exam to evaluate
light spots
• Recommend an initial treatment plan for selected light rashes
• Determine when to refer to a patient with a light rash to a
dermatologist
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Case One
Heather Doyle
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Case One: History
 HPI: Heather Doyle is a 10-year-old girl who presents with
several lightly colored spots on her knees and hands over the
past 8 months. They do not itch. Her mother reports they have
not improved with over-the-counter hydrocortisone cream.
 PMH: no chronic illnesses or prior hospitalizations
 Allergies: penicillin (rash)
 Medications: none
 Family history: grandmother with diabetes
 Social history: lives at home with parents; attends elementary
school; takes karate lessons
 ROS: negative
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Case One: Skin Exam
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Case One, Question 1
 Heather has some light colored, non-scaly,
flat spots on her knees. Which of the
following will likely aid in the diagnosis?
a.
b.
c.
d.
Dermatoscope
Potassium hydroxide (KOH) exam
Swab for bacterial culture
Wood’s light
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Case One, Question 1
Answer: d
 Heather has some light colored, non-scaly,
flat spots on her knees. Which of the
following will likely aid in the diagnosis?
a.
b.
c.
d.
Dermatoscope
Potassium hydroxide (KOH) exam
Swab for bacterial culture
Wood’s light
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Case One: Wood’s light exam
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Case One, Question 2
 How would you describe Heather’s exam?
a. well-circumscribed hypopigmented macules
and patches
b. well-circumscribed depigmented macules and
patches
c. poorly circumscribed hypopigmented macules
and patches
d. poorly circumscribed hypopigmented papules
and plaques
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Case One, Question 2
Answer: b
 How would you describe Heather’s exam?
a. well-circumscribed hypopigmented macules and
patches
b. well-circumscribed depigmented macules and
patches
c. poorly circumscribed hypopigmented macules and
patches
d. poorly circumscribed hypopigmented papules and
plaques
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Vitiligo
 Lesions of vitiligo are wellcircumscribed depigmented
macules and patches.
 The Wood’s light exam
distinguishes hypopigmented
and depigmented lesions.
 Very few rashes other than
vitiligo are completely
depigmented.
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More Examples of Vitiligo
 Demonstration of bright white (depigmented) area
with Wood’s light illumination
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Vitiligo: The Basics
 Vitiligo is caused by an autoimmune attack
on melanocytes, the cells that produce skin
pigment
 It favors areas of trauma (knees, elbows,
fingers, mouth, eyes, genitalia)
 There is an association with other
autoimmune disorders
• Heather’s vitiligo may be autoimmune, given her
family history
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Vitiligo: The Basics
 Treatment options include
• Potent topical steroids or tacrolimus
ointment
• Phototherapy (Narrow band UVB, UVA)
• Cosmetic cover-ups
 Refer vitiligo patients to dermatology
for initial evaluation
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Is this hypopigmented or
depigmented? Use the Wood’s light.
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Wood’s light exam
 Lighter areas without complete loss of pigment
are “hypopigmented”
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Steroid hypopigmentation
 Skin lightening can result from potent topical or
intralesional corticosteroids
 The risk is higher in darker skin types. Counsel
patients and parents on this risk.
 Avoid this side effect by using appropriate strength
topical steroids
• Use high-potency steroids for short durations
• Then back off to mid-potency or low-potency steroids for
maintenance
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Case Two
Tony Maddox
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Case Two: History
 HPI: Tony Maddox is a 32-year-old man who presents
with “blotches” on his upper back and chest for several
years. They are more noticeable in the summertime.
 PMH: back pain, hyperlipidemia, birthmark (Nevus of
Ito) on his left chest
 Allergies: none
 Medications: NSAID as needed
 Family history: none
 Social history: aircraft mechanic
 ROS: negative
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Case Two: Skin Exam
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Case Two, Question 1
 Mr. Maddox’s skin exam shows hypopigmented,
slightly scaly macules on his upper chest.
Which is the best test to confirm the diagnosis?
a.
b.
c.
d.
Bacterial culture
Direct fluorescent antibody (DFA) test
Potassium hydroxide (KOH) exam
Wood’s light
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Case Two, Question 1
Answer: c
 Mr. Maddox’s chest shows hypopigmented,
slightly scaly macules on his upper chest.
Which is the best test to confirm the diagnosis?
a.
b.
c.
d.
Bacterial culture
Direct fluorescent antibody (DFA) test
Potassium hydroxide (KOH) exam
Wood’s light
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Case Two: KOH exam
Spores (yeast forms)
Short
Hyphae
The KOH exam shows short hyphae and small round spores. This is
diagnostic of tinea (pityriasis) versicolor.
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Diagnosis: Tinea versicolor
 Based on his skin findings and KOH
exam, Mr. Maddox has tinea
versicolor
 It’s called “versicolor” because it can
be light, dark, or pink to tan
 Let’s look at some examples of the
various colors of tinea versicolor
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Tinea versicolor: lighter
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Tinea versicolor: darker
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Tinea versicolor: pink or tan
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Case Two, Question 2
 What is the best treatment for Mr. Maddox?
a.
b.
c.
d.
e.
Ketoconazole shampoo
Narrow band UVB phototherapy
Oral griseofulvin
Tacrolimus cream
Triamcinolone cream
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Case Two, Question 2
Answer: a
 What is the best treatment for Mr. Maddox?
a. Ketoconazole shampoo
b. Narrow band UVB phototherapy (may
worsen appearance by increasing contrast)
c. Oral griseofulvin (does not work for
Malassezia species)
d. Tacrolimus cream (does not fight yeast)
e. Triamcinolone cream (does not fight yeast) 30
Case Two, Question 3
 What is true about the treatment of tinea
versicolor?
a. Normal pigmentation should return within a
week of treatment
b. Oral azoles should be used in most cases
c. When using shampoos as body wash, leave
on for ten minutes before rinsing
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Case Two, Question 3
Answer: c
 What is true about the treatment of tinea
versicolor?
a. Normal pigmentation should return within a week of
treatment (usually takes weeks to months to return to
normal)
b. Oral azoles should be used in most cases (mild cases
can be treated with topicals)
c. When using shampoos as body wash, leave on for
ten minutes before rinsing
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Case Three
Shaun Lee
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Case Three: History
 HPI: Shaun Lee is a 20-year-old male seen in the hospital with
a worsening light colored scaling rash on his face. It has been
getting worse since he stopped taking HAART for HIV. He also
has painful erosions and ulcers in his mouth for 2 months and
was admitted for pneumonia.
 PMH: HIV, extensive molluscum contagiosum, pneumonia
 Allergies: penicillin (rash)
 Medications: levofloxacin
 Family history: noncontributory
 Social history: lives at home with parents; father does not
believe he should take HIV medications
 ROS: fatigue, dyspnea, fevers
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Case Three: Skin Exam
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Case Three, Question 1
 Shaun’s exam shows hypopigmented scaling
patches on his central face, eyebrows, and
hairline. KOH is negative. What is the most
likely diagnosis?
a.
b.
c.
d.
Pityriasis alba
Seborrheic dermatitis
Steroid hypopigmentation
Tinea versicolor
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Case Three, Question 1
Answer: b
 Shaun’s exam shows hypopigmented scaling
patches on his central face, eyebrows, and
hairline. KOH is negative. What is the most
likely diagnosis?
a.
b.
c.
d.
Pityriasis alba (no history of atopy)
Seborrheic dermatitis
Steroid hypopigmentation (not using steroids)
Tinea versicolor (wrong location)
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Seborrheic dermatitis
 Seborrheic dermatitis is a very common inflammatory
reaction to the Malassezia (Pityrosporum ovale)
yeast that thrives on seborrheic (oil-producing) skin
 It presents as erythematous scaling macules on the
scalp, hairline, eyebrows, eyelids, central face and
nasolabial folds, external auditory canals, or central
chest
 It can be hypopigmented, especially in darker skin
types
 Seborrheic dermatitis is often worse in HIV-positive
individuals
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Seborrheic dermatitis
Often hypopigmented
in darker skin types
39
Seborrheic dermatitis
Favors central chest. May be
hypopigmented or erythematous.
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Case Three, Question 2
 What is the best treatment for Shaun?
a. Caspofungin IV infusion
b. Clobetasol proprionate cream (high potency
steroid)
c. Desonide cream (low potency steroid)
d. Imiquimod cream
e. Narrow band UVB phototherapy
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Case Three, Question 2
Answer: c
 What is the best treatment for Shaun?
a. Caspofungin IV infusion (this is a systemic
antifungal for severe infections)
b. Clobetasol proprionate cream (would work, but
too potent for use on the face)
c. Desonide cream (low potency steroid)
d. Imiquimod cream (irritating; for warts, actinic
keratoses)
e. Narrow band UVB phototherapy (doesn’t work) 42
Seborrheic dermatitis treatment
 Antidandruff shampoo
• Ketoconazole (Nizoral), selenium sulfide, zinc
pyrithione (Head & Shoulders) shampoos
• Lather, leave on 10 minutes, rinse
• 3-5 times weekly until under control
 Low-potency topical steroid (e.g. desonide) for
flares
• Use BID for 1-2 weeks for flares
 Can also use topical ketoconazole or ciclopirox, or
topical pimecrolimus
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Seborrheic dermatitis (scalp)
 Severe scalp seborrheic dermatitis may need
topical steroids; adjust to severity, patient ethnicity
 Triamcinolone spray BID for flares
 Fluocinolone in peanut oil (DermaSmooth™)
• Wet scalp; leave on 8 hours then wash out
• If wash hair daily, apply at night with shower
cap
• If not, use a little oil each morning
 Clobetasol foam daily after shower if severe
• Towel dry and apply directly to damp scalp 44
A note on postinflammatory
hypopigmentation
 Some patients heal with
light spots from any rash
 Stigma may be caused by
fear of infectious diseases
 Social impact can be more
severe than original rash
 Pigmentation may return
slowly
 It is important to treat
rashes aggressively to
avoid this if possible
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Case Four
Damien Gonsalves
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Case Four: History
 HPI: Damien Gonsalves is a 8-year-old boy who
presents with light spots on his face.
 PMH: had “eczema” as infant and young child
 Allergies: none
 Medications: none
 Family history: brother with asthma, mother has
seasonal allergic rhinitis
 Social history: lives at home with parents; student in
second grade
 ROS: negative
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Case Four: Skin Exam
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Case Four: Question
 Damien has hypopigmented patches on his
cheeks bilaterally. The most likely diagnosis is:
a. Pityriasis alba
b. Seborrheic dermatitis
c. Tinea versicolor
d. Vitiligo
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Case Four: Question
Answer: a
 Damien has hypopigmented patches on his
cheeks bilaterally. The most likely diagnosis is:
a. Pityriasis alba (atopic history supports this)
b. Seborrheic dermatitis (usually more central)
c. Tinea versicolor (rarely occurs on the face)
d. Vitiligo (would be depigmented, not
hypopigmented)
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Pityriasis alba
 Pityriasis alba is a mild form of atopic dermatitis of
the face in children
 As in all atopic dermatitis, the first goal is
moisturization
 Use of sunscreens minimizes tanning, thereby
limiting the contrast between involved and normal
skin
 If moisturization and sunscreen do not improve the
hypopigmentation, consider low strength topical
steroid
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Common light rashes




Vitiligo
Tinea versicolor
Seborrheic dermatitis
Pityriasis alba
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Comparing common light rashes
Face
Seborrheic
dermatitis
X
Tinea versicolor
Vitiligo
Trunk
+
Notes
Central face
Greasy scale
X
X
X
Arms,
Legs
+
X
KOH positive
Depigmented (“bone
white”) on Woods
light exam
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Pityriasis alba
X
History of atopy
Take Home Points: Light Rashes
 Vitiligo is totally depigmented (“bone white”) on Wood’s light
examination
 Hypopigmented macules on the upper back and chest should
be scraped for KOH exam to rule out tinea versicolor
 Hypopigmented patches on the central face with greasy scale
are usually seborrheic dermatitis
 Hypopigmented patches on the face of atopic children are
usually pityriasis alba; reassure parents and encourage use of
sunscreen and moisturizers
 Potent corticosteroids can cause hypopigmentation, so be
aware of that when prescribing or injecting, and warn patients
of this possible side effect when appropriate
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Acknowledgements
 This module was developed by the American
Academy of Dermatology Medical Student Core
Curriculum Workgroup from 2008-2012.
 Primary author: Patrick McCleskey, MD, FAAD.
 Peer reviewers: Timothy G. Berger, MD, FAAD;
Peter A. Lio, MD, FAAD; Jennifer Swearingen,
MD; Sarah D. Cipriano, MD, MPH.
 Revisions: Patrick McCleskey, MD, FAAD.
 Last revised April 2011.
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End of the Module
 Berger T, Hong J, Saeed S, Colaco S, Tsang M, Kasper R. The WebBased Illustrated Clinical Dermatology Glossary. MedEdPORTAL; 2007.
Available from: www.mededportal.org/publication/462.
 Habif TP. Clinical Dermatology: a color guide to diagnosis and therapy,
4th ed. New York, NY: Mosby; 2004.
 Layton AM, Cunliffe WJ. Minocycline induced skin pigmentation in the
treatment of acne—a review and personal observations. J Dermatol
Treatment 1989;1:9-12.
 Lio PA. Little white spots: an approach to hypopigmented macules.
Arch Dis Child Pract Ed 2008;93:98-102.
 Marks Jr JG, Miller JJ. Chapter 13. White Spots (chapter). Lookingbill
and Marks’ Principles of Dermatology, 4th ed. Elsevier; 2006:187-197.
 Wolverton SE. Systemic drugs for infectious diseases (Chapter 5) and
Topical Antifungal Agents (Chapter 29). Comprehensive Dermatologic
Drug Therapy, 2nd ed. Elsevier; 2007: 80-99, 547-559.
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