Hyperpigmentation
Disorders of hyperpigmentation can be focal or diffuse. In diffuse hyperpigmentation, it is important to search carefully for an underlying endocrine or other systemic disease, or a history of medications or heavy metals that may explain the findings. See “Pigmented Lesions” entry for discussion of focal hyperpigmentation, which may be caused by hormonal influences (e.g., birth control pills, pregnancy)
Differential Diagnosis
- Acanthosis nigricans
–Velvety, hyperpigmented thickening of skin folds (e.g., axillae, groin, neck, and inframammary regions)
–Associated with insulin resistance (e.g., DM, Cushing's diseases, hypothyroidism, obesity, polycystic ovarian syndrome, and exogenous corticosteroids)
- Tinea versicolor
–Mottled macular hyperpigmentation (and/or hypopigmentation) in rings and circles with little or no scale
–Often on the upper trunk and shoulders
–Caused by Pityrosporum orbiculare and P. ovale, which look like “spaghetti and meatballs” on KOH preparation
–May be pruritic during acute phase, particularly in warm environments that encourage growth of the fungus - Postinflammatory hyperpigmentation
–Patchy, transient hyperpigmentation after resolution of inflammatory rashes
- Melasma (chloasma, “mask of pregnancy”)
–Gradual blotchy macular hyperpigmentation, especially of the malar surfaces, chin, and forehead
–Occurs with oral contraceptives, pregnancy, or idiopathic
–May fade postpartum or after discontinuing oral contraceptives, and recur if either occurs again
- Grey or blue hyperpigmentation
–Medications: Amiodarone, minocycline, imipramine, chemotherapeutic drugs (e.g., bleomycin, doxorubicin), antimalarials, AZT
–Heavy metal poisoning
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Incontinentia pigmenti
–Genetic disorder with associated systemic abnormalities; the final stage of skin disease can present as linear and whorled streaks or hyperpigmentation
Hemochromatosis
–Diffuse hyperpigmentation
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Diabetic dermopathy
–Hyperpigmented, round, atrophic lesions on shins of diabetics
Mongolian spots
Workup and Diagnosis
-
History and physical examination
–Review the patient's medication list to rule out drug-induced pigmentation or melasma
–Note whether rash, erythema, or scale preceded the hyperpigmentation
–Heavy or irregular menses, hirsutism, and/or obesity may suggest PCOS
Diffuse hyperpigmentation must be evaluated for underlying endocrine disorder; initial laboratory testing includes CBC, LFTs and iron profile (rule out hemochromatosis), fasting glucose (rule out diabetes), ACTH level (rule out Addison's disease), cosyntropin stimulation tests (rule out Cushing's disease)
Trunk and chest lesions should have a KOH preparation performed (round “spores” and short nonbranching blunt hyphae to diagnose tinea versicolor)
Age-appropriate malignancy screening is warranted in patients with acanthosis nigricans and no evidence of endocrine dysfunction
Treatment
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Acanthosis nigricans improves with adequate treatment of the underlying endocrine disorder; treatments may include weight loss, dietary/medication control of insulin resistance, and topical exfoliants (e.g., lactic acid, tretinoin, urea-based medications)
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Tinea versicolor: Treatment includes topical (e.g., ketoconazole) or oral antifungals (e.g., fluconazole); normalization of pigmentation may take many months; long-term maintenance therapy is necessary to prevent recurrence
-
Melasma often improves spontaneously after pregnancy or discontinuation of oral contraceptives; sun avoidance and topical retinoids and hydroquinones facilitate normalization of pigment; chemical peels or laser procedures restore normal pigmentation
-
Avoid offending medications; adjuvant laser therapy may be necessary to remove or destroy residual drug particles, hemosiderin, or excess melanin in skin
Book Source Details
- Book Title: In a Page: Signs and Symptoms
- Author(s): Scott Kahan, Ellen G. Smith
- Year of Publication: 2004
- Copyright Details: In a Page: Signs and Symptoms, Copyright © 2004 Lippincott Williams & Wilkins.
Other Book Chapters Related to Hyperpigmentation
Read excerpts from these other book chapters related to Hyperpigmentation:
Copyright Details: In a Page: Signs and Symptoms, Copyright © 2008 Williams & Wilkins.
More About Causes of Hyperpigmentation
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More About This Book:
Title: In a Page: Signs and Symptoms
Authors: Scott Kahan, Ellen G. Smith
Publisher: Lippincott Williams & Wilkins
Copyright: 2004
ISBN: 1-4051-0368-X
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» Next page: Pigmented Lesions (In a Page: Signs and Symptoms)
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