1. Medical Student Core Curriculum in Dermatology
Blotches: Dark rashes
Medical Student Core Curriculum
in Dermatology
Last updated April 18, 2011

2. 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.

3. 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 hyperpigmented rashes.
After completing this module, the medical student will be able to:
Identify and describe the morphology of common hyperpigmented rashes
Provide an initial treatment plan for selected dark rashes
Determine when to refer a patient with a dark rash to a dermatologist

4. Case One
Scott Goff

5. Case One: History
HPI: Scott Goff is a 28-year-old male who presents with “blotches” on his upper back and chest for several years. They do not cause any symptoms other than anxiety because he has these dark spots.
PMH: no major illnesses or hospitalizations
Allergies: none
Medications: protein supplements
Family history: none
Social history: accountant; weightlifter
ROS: negative

6. Case One: Skin Exam

7. Case One: Skin Exam

8. Case One, Question 1
Mr. Goff’s chest shows hyperpigmented, scaly macules on his upper chest and back. Which is the best test to confirm the diagnosis?
Bacterial culture
Direct fluorescent antibody (DFA) test
Potassium hydroxide (KOH) exam
Wood’s light

9. Case One, Question 1 Answer: c
Mr. Goff’s chest shows hyperpigmented, scaly macules on his upper chest and back. Which is the best test to confirm the diagnosis?
Bacterial culture
Direct fluorescent antibody (DFA) test
Potassium hydroxide (KOH) exam
Wood’s light

10. Case One, KOH exam Spores (yeast forms) Short Hyphae
The KOH exam shows short hyphae and small round spores. This is diagnostic of tinea (pityriasis) versicolor.

11. Diagnosis: Tinea versicolor
Based on his skin findings and KOH exam, Mr. Goff 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

12. Tinea versicolor: lighter

13. Tinea versicolor: darker

14. Tinea versicolor: pink or tan

15. Case One, Question 2 What is the best treatment for Mr. Goff?
Ketoconazole shampoo
Narrow band UVB phototherapy
Oral griseofulvin
Tacrolimus cream
Triamcinolone cream

16. Case One, Question 2 Answer: a
What is the best treatment for Mr. Goff?
Ketoconazole shampoo
Narrow band UVB phototherapy (may worsen appearance by increasing contrast)
Oral griseofulvin (does not work for Malassezia species)
Tacrolimus cream (does not fight yeast)
Triamcinolone cream (does not fight yeast)

17. Case One, Question 3
Which of the following statements is true about the treatment of tinea versicolor?
Normal pigmentation should return within a week of treatment
Oral azoles should be used in most cases
When using shampoos as body wash, leave on for ten minutes before rinsing

18. Case One, Question 3 Answer: c
Which of the following statements is true about the treatment of tinea versicolor?
Normal pigmentation should return within a week of treatment (usually takes weeks to months to return to normal)
Oral azoles should be used in most cases (mild cases can be treated with topicals)
When using shampoos as body wash, leave on for ten minutes before rinsing

19. Case Two
Melinda Kinsley

20. Case Two: History
HPI: Melinda Kinsley is a 48-year-old Guatemalan woman who presents with ten years of dark spots on her face. She tried a bleaching cream she got from Mexico but her friend told her it could make the spots worse.
PMH: three normal pregnancies; s/p tubal ligation
Allergies: none
Medications: supplements black cohosh, evening primrose
Family history: noncontributory
Social history: lives with husband and children
ROS: negative

21. Case Two: Skin Exam

22. Case Two, Question 1
Which of the following is most likely associated with this symmetric hyperpigmentation?
Ginseng
Limes
Minocycline
Malassezia furfur
Pregnancy

23. Case Two, Question 1 Answer: e
Which of the following is most likely associated with this symmetric hyperpigmentation?
Ginseng
Limes
Minocycline
Malassezia furfur
Pregnancy

24. Melasma

25. Melasma (aka Chloasma)
Melasma is characterized by patchy light to dark brown hyperpigmentation of the face
Usually affects women, runs in families
Associated with hormonal changes
Called the “mask of pregnancy”
May occur with pregnancy, birth control pills, and hormone replacement therapy

26. Melasma (aka Chloasma)
Worse with exposure to UV radiation
Treatments
Strict sun avoidance, daily sunscreen with broad spectrum coverage and SPF > 30
Hydroquinone 4% cream BID
If this fails, may refer to dermatology for cosmetic treatments like triple topical therapy, lasers, or chemical peels, but these will usually be at the patient’s expense

27. Case Three
Henry Fontana

28. Case Three: History
HPI: Henry Fontana is a 78-year-old man who presents with of darkening of his arms and neck over the past few years. He recently underwent knee replacement surgery, and the orthopedist noticed a greenish pigmentation of his bones.
PMH: hypertension, GERD, osteoarthritis, BPH, basal cell and squamous cell carcinomas, rosacea
Allergies: none
Medications: atenolol, felodipine, celecoxib, oxybutinin, rabeprazole, minocycline
Family history: noncontributory
Social history: widower; lives alone
ROS: negative

29. Case Three: Skin Exam

30. Case Three, Question 1
Which of the following medications is most likely associated with this pigmentation?
Atenolol
Celecoxib
Minocycline
Oxybutinin
Rabeprazole

31. Case Three, Question 1 Answer: c
Which of the following medications is most likely associated with this pigmentation?
Atenolol
Celecoxib
Minocycline
Oxybutinin
Rabeprazole

32. Minocycline pigmentation

33. Minocycline pigmentation
Deposition appears after months to years in a small percentage of patients
First noticeable on the alveolar ridge, palate, sclera
May involve bones, thyroid, but this is harmless
Skin deposition can be brown or blue-grey
Blue-grey pigmentation may occur in scars
Skin pigmentation may not fade after discontinuation
Patients on long-term minocycline should be screened; if seen on gums or sclerae, discontinue

34. Other causes of medication-related hyperpigmentation
Amiodarone
Antimalarials
Hydroxychloroquine
Chloraquine
Calcium channel blockers
Verapamil
Diltiazem
Zidovudine
Imipramine
Some antipsychotics
Some chemotherapy agents

35. Case Four
Elaine Gosnel

36. Case Four: History
HPI: Elaine Gosnel is a 66-year-old woman with a two-year history of an itchy rash on her legs that has resulted in dark spots.
PMH: hypertension, diabetes, hyperlipidemia
Allergies: none
Medications: metoprolol, simvastatin, metformin
Family history: noncontributory
Social history: widowed; lives in a retirement community
ROS: edematous legs

37. Case Four: Skin Exam

38. Case Four, Question 1
The patient’s legs show scaly brown plaques on her lower legs bilaterally. Pedal pulses are normal. What is the most likely diagnosis for Mrs. Gosnel’s rash?
Atopic dermatitis
Erysipelas
Irritant contact dermatitis
Stasis dermatitis
Tinea corporis

39. Case Four, Question 1 Answer: d
The patient’s legs show scaly brown plaques on her lower legs bilaterally. Pedal pulses are normal. What is the most likely diagnosis for Mrs. Gosnel’s rash?
Atopic dermatitis (wrong location, no history)
Erysipelas (usually unilateral, acute not chronic)
Irritant contact dermatitis (not good location, no history)
Stasis dermatitis
Tinea corporis (more superficial)

40. Stasis dermatitis

41. Case Four, Question 2
You correctly diagnose Mrs. Gosnel with stasis dermatitis. What do you recommend?
Bacitracin ointment twice daily
Daily oral trimethoprim-sulfamethoxazole
Debridement of superficial erosions
Elevation and compression stockings
Immediate referral to vascular surgery

42. Case Four, Question 2 Answer: d
You correctly diagnose Mrs. Gosnel with stasis dermatitis. What do you recommend?
Bacitracin ointment twice daily (likely to cause allergic contact dermatitis)
Daily oral trimethoprim-sulfamethoxazole (no active infection)
Debridement of superficial erosions (may worsen)
Elevation and compression stockings
Immediate referral to vascular surgery (not indicated for most stasis dermatitis)

43. Stasis dermatitis
Venous stasis dermatitis is an eczematous eruption that occurs in venous insufficiency and leg edema
Acute eczematous dermatitis (itchy red scaly plaques) leads to chronic eczematous dermatitis; may be weepy
Extravasation leads to brown pigmentation and petechiae
Venous ulcers may result, especially on medial malleolus
Refer to the module on Stasis Dermatitis and
Leg Ulcers for more information

44. Stasis dermatitis: Treatment
Reduce edema with elevation and compression stockings
Wet compresses may aid in healing erosions or ulcers
Mid-potency topical steroids control inflammation
Avoid topical antibiotics because up to half develop allergic contact dermatitis, especially to neomycin and bacitracin

45. Quick Case: Dark spot on the leg
This 32-year-old man who had a small laceration two years ago and presents with a dark spot
He’s worried it might be something bad

46. Quick Case: Diagnosis? What is the most likely diagnosis?
Drug-induced pigmentation
Melanoma
Postinflammatory hyperpigmentation
Post-traumatic fungal infection

47. Quick Case: Diagnosis? Answer: c What is the most likely diagnosis?
Drug-induced pigmentation
Melanoma
Postinflammatory hyperpigmentation
Post-traumatic fungal infection

48. Postinflammatory hyperpigmentation
Postinflammatory hyperpigmentation describes a common phenomenon of darkening of the skin at or around sites of injury or inflammation
Individuals with olive or slightly darker complexion are at particular risk
The pigmentation takes months to years to fade but usually improves gradually over time

49. Postinflammatory hyperpigmentation
Reassure patients this is normal
This is not a scar; it’s just increased pigment
Use sunscreen after injuries or surgical procedures
For significant or problematic hyperpigmentation, refer to a dermatologist

50. Postinflammatory hypopigmentation
Some patients heal with light spots instead
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

51. Common dark rashes Tinea versicolor Melasma Drug pigmentation
Stasis dermatitis
Postinflammatory hyperpigmentation

52. Take Home Points: Dark Rashes
Tinea versicolor may be hyperpigmented
Symmetric brown patches on the zygomatic, buccal, and mandibular cheeks of adult women are usually melasma
Some medications (especially minocycline) cause hyperpigmentation; warn patients and monitor for it
Venous stasis can cause hyperpigmentation
Postinflammatory hyperpigmentation and hypopigmentation are very common in darker skin types, so treat skin conditions aggressively

53. Acknowledgements
This module was developed by the American Academy of Dermatology Medical Student Core Curriculum Workgroup from
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.

54. References
Berger T, Hong J, Saeed S, Colaco S, Tsang M, Kasper R. The Web- Based Illustrated Clinical Dermatology Glossary. MedEdPORTAL; Available from:
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:
Marks Jr JG, Miller JJ. Chapter 13. White Spots (chapter). Lookingbill and Marks’ Principles of Dermatology, 4th ed. Elsevier; 2006:
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,