Pigmentation Disorders
Michael L. O’Dell
Patients often present complaining of lighter or darker patches of skin. These complaints represent a range of minor to quite serious illnesses.
Approach
Classify the complaint into a hyperpigmentation disorder or a hypopigmentation disorder (1).
A. Disorders of hyperpigmentation include pityriasis versicolor, café au lait macule, melasma, acanthosis nigricans, Becker’s melanosis, drug eruptions, and postinflammatory hyperpigmentation.
B. Disorders of hypopigmentation include vitiligo, pityriasis alba, ash leaf macules, and postinflammatory hypopigmentation.
History
A. Onset
1. Hyperpigmented lesions. An upper back or chest rash following exposure to a humid and warm climate is typical for young adults with pityriasis versicolor. Café au lait macules are present at birth and regress with time. Melasma occurs in women with pregnancy, institution of oral contraceptives, liver dysfunction, or phenytoin use. Acanthosis nigricans becomes noticeable with weight gain. Becker’s melanosis occurs after severe sun exposure in teenagers and young adults. Drug-induced hyperpigmentation is associated with many drugs, especially minocycline and zidovudine. Fixed hyperpigmenting drug reactions are common with exposures to phenolphthalein, barbiturates, phenacetin, salicylates, tetracyclines, and sulfonamides. Inflammation of the skin caused by nearly any agent can result in hyperpigmentation.
2. Hypopigmented lesions. Vitiligo, which generally starts between ages 10 and 30 years, can be associated with stress, illness, and personal crises. Pityriasis alba occurs in young children and is generally associated with eczema. Ash leaf macules, which are rare, are found in patients with tuberous sclerosis. Inflamed skin can depigment following inflammation.
B. Duration. Most pigment disorders are generally long-lasting.
C. Exacerbating factors
1. Hyperpigmented disorders. Pityriasis versicolor worsens with continued exposure to heat and humidity and with malnutrition. Melasma worsens with pregnancy and continued exposure to medications or deterioration of liver function. Acanthosis nigricans worsens with weight gain and can increase with the use of insulin, nicotinic acid, glucocorticoids, or estrogens. Drug-induced hyperpigmentation and eruptions worsen with each exposure to the offending agent. With continued inflammation, postinflammatory hyperpigmentation worsens.
2. Hypopigmented disorders. Vitiligo can worsen with stress, illness, and personal crises, and with skin trauma. Pityriasis alba can worsen from use of drying agents (e.g., soap) or by sunlight.
D. Relieving factors
1. Hyperpigmented disorders. Café au lait macules regress with age. Melasma can improve, but rarely vanishes, after delivery or removal of the offending agent. Acanthosis nigricans improves with weight loss and removal of offending medications. Fixed drug reactions can fade after removal of the agent, but often remain. Minocycline-induced hyperpigmentation is often permanent. Inflammatory changes often fade slowly over several months.
2. Hypopigmented disorders. Vitiligo rarely spontaneously repigments and it is generally progressive. Pityriasis alba improves with age and moisturizing of the affected skin.
E. Associated symptoms
1. Hyperpigmented disorders. Pityriasis versicolor is often itchy. Café au lait spots can be a marker for neurofibromatosis with associated neurologic symptoms, especially if six or more of the macules are present. Melasma per se, is asymptomatic, as is acanthosis nigricans. Acanthosis nigricans is often associated with diabetes and may even be a marker for diabetes (2). It can be associated with underlying malignancy as well. Becker’s melanosis may be slightly itchy. Fixed drug reactions can be painful or itchy. Other drug-induced hyperpigmentation is usually asymptomatic. On resolution of inflammation, postinflammatory lesions are usually asymptomatic.
2. Hypopigmented disorders. The lesions of vitiligo are usually asymptomatic, but depression is commonly associated with vitiligo (3). Lesions of pityriasis alba can be slightly itchy or burning. Ash leaf macules are often associated with tuberous sclerosis and its associated neurologic symptoms.
Physical examination
A. Hyperpigmented disorders, lesion description. Pityriasis versicolor begins as a reddish macule, generally on the upper back, appearing darker than surrounding skin during winter and lighter than tanned skin during summer. Café au lait macules are 0.2 to 10 cm, uniform, well demarcated, brown areas found on sun-protected sites of the trunk and extremities. Melasma generally is most prominent on the malar eminence and other sun-exposed areas. Acanthosis nigricans is thickened plaques in a symmetric pattern in the axillae, neck, groin, and folds of the breast and groin. Acanthosis nigricans neck lesions often appear as dirty or unwashed skin. Mecke’s melanosis is a hyperpigmented macule of varied size, generally solitary and with thick and darkened hair. Acneiform eruptions are often present in the center of the lesion. Minocycline-induced hyperpigmentation can occur in old scars, on the lower extremities and forearms, or diffusely in sun-exposed areas. Fixed drug eruptions occur in the same place with each exposure; initially, they can be vesicobullous, and then resolve as a hyperpigmented patch. Postinflammatory hyperpigmentation is generally light brown to black discoloration in an area of previous inflammation.
B. Hypopigmented disorders, lesion description. Vitiligo appears as depigmented macules with scalloped edges, initially generally on the face, hands, wrists, axillae, umbilicus, and genitalia. The macules often coalesce with time into larger areas of depigmentation. Pityriasis alba appears as a small macule, failing to tan, that is pale pink to light brown with irregular borders on the midforehead, malar ridge, periorbital area, or perioral area. Ash leaf macules are hypopigmented lesions appearing with one end rounded and the other pointed (lance ovate) resembling an ash tree leaf. They can occur in normal children; if accompanied by acnelike lesions, however, they are particularly suspicious, as markers for tuberous sclerosis.
C. Ophthalmologic examination is important for patients with vitiligo, as pigmentation abnormalities of the choroid and retina can lead to poor visual acuity or blindness.
D. Lung examination of children with pityriasis alba is useful, because atopy and asthma often coexist.
E. A complete physical examination, searching for underlying malignancy is necessary in patients with rapid onset of acanthosis nigricans, especially if it occurs without weight loss or in the absence of diabetes.
F. Neurologic examination is necessary in persons with café au lait macules or ash leaf spots.
Testing
A. Hyperpigmented disorders. Skin scraping of pityriasis versicolor may reveal the characteristic “spaghetti and meatballs” appearance of Malassezia furfur, the causative organism. Wood’s light illumination often reveals a yellow-gold luminescence. More than six café au lait macules should prompt an evaluation for neurofibromatosis (1). Evaluate the patient with unexplained acanthosis nigricans for possible diabetes or underlying tumor, especially gastrointestinal adenocarcinomas.
B. Hypopigmented disorders. Vitiligo can be associated with diabetes, adrenal insufficiency, or pernicious anemia, and patients with signs of these illnesses should be evaluated appropriately. Have patients with ash leaf macules screened for tuberous sclerosis.
Diagnostic assessment
Patients with pigmentary disorders are best initially classified into disorders of excessive pigmentation or hypopigmentation. History is useful in eliciting inciting factors, especially drug-induced or inflammation-induced changes. Characteristic appearances of the lesions further define the illness. Biopsy of lesions is generally not necessary, although selected lesions may require further testing for underlying diseases.
References
1. Kim NY, Pandya AG. Pigmentary diseases. Med Clin North Am 1998;82(5):
1185–1207.
2. Stuart CA. Ananthosis nigricans as a risk factor for non-insulin dependent diabetes mellitus. Clin Pediatr 1998;37(2):73–79.
3. Agarwal G. Vitiligo: an under-estimated problem. Fam Pract 1998;15(Suppl):S19–S23.
Book Source Details
- Book Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
- Author(s): Robert B. Taylor (editor)
- Year of Publication: 2000
- Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2000 Lippincott Williams & Wilkins.
Other Book Chapters Related to Hyperpigmentation
Read excerpts from these other book chapters related to Hyperpigmentation:
Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2008 Williams & Wilkins.
More About Causes of Hyperpigmentation
» Next page: Hypo/Hyperpigmentation (Field Guide to Bedside Diagnosis)
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