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Blotches:Light rashes
Basic Dermatology Curriculum
Last updated April 18, 2011
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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
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. Dermatoscope
b. Potassium hydroxide (KOH) exam
c. Swab for bacterial culture
d. 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. Dermatoscope
b. Potassium hydroxide (KOH) exam
c. Swab for bacterial culture
d. Wood’s light
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 well-circumscribed depigmented macules and patches.
The Wood’s light exam distinguishes hypopigmented and depigmented lesions.
Very few rashes other than vitiligo are completely depigmented.
More Examples of Vitiligo
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Demonstration of bright white (depigmented) area with Wood’s light illumination
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 history14
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 evaluation15
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
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. Bacterial culture
b. Direct fluorescent antibody (DFA) test
c. Potassium hydroxide (KOH) exam
d. 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. Bacterial cultureb. Direct fluorescent antibody (DFA) testc. Potassium hydroxide (KOH) examd. Wood’s light
Case Two: KOH exam
The KOH exam shows short hyphae and small round spores. This is diagnostic of tinea (pityriasis) versicolor.
Spores (yeast forms)
ShortHyphae
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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. Ketoconazole shampoo
b. Narrow band UVB phototherapy
c. Oral griseofulvin
d. Tacrolimus cream
e. 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)
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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
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. Pityriasis alba
b. Seborrheic dermatitis
c. Steroid hypopigmentation
d. Tinea versicolor
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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. Pityriasis alba (no history of atopy)
b. Seborrheic dermatitis
c. Steroid hypopigmentation (not using steroids)
d. Tinea versicolor (wrong location)
Case Three, Question 1
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 38
Seborrheic dermatitis
Often hypopigmented in darker skin types
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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)
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
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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
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 Trunk Arms, Legs Notes
Seborrheic dermatitis X X Central face
Greasy scale
Tinea versicolor X + KOH positive
Vitiligo X + XDepigmented (“bone
white”) on Woods light exam
Pityriasis alba X History of atopy
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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 54
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 Web-
Based 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.