Hyperpigmentation [Hypermelanosis]
Hyperpigmentation, or excessive skin coloring, usually reflects overproduction, abnormal location, or maldistribution of melanin—the dominant brown or black pigment found in skin, hair, mucous membranes, nails, brain tissue, cardiac muscle, and parts of the eye. This sign can also reflect abnormalities of other skin pigments: carotenoids (yellow), oxyhemoglobin (red), and hemoglobin (blue).
Hyperpigmentation most commonly results from exposure to sunlight. However, it can also result from metabolic, endocrine, neoplastic, and inflammatory disorders; chemical poisoning; drugs; genetic defects; thermal burns; ionizing radiation; and localized activation by sunlight of certain photosensitizing chemicals on the skin.
Many types of benign hyperpigmented lesions occur normally. Some, such as acanthosis nigricans and carotenemia, may also accompany certain disorders, but their significance is unproven. Chronic nutritional insufficiency may lead to dyspigmentation—increased pigmentation in some areas and decreased pigmentation in others.
Typically asymptomatic and chronic, hyperpigmentation is a common problem that can have distressing psychological and social implications. It varies in location and intensity and may fade over time.
History and physical examination
Hyperpigmentation isn’t an acute process, but an end result of another process, which should be the main target of your examination. Begin with a detailed patient history. Do any other family members have the same problem? Was the patient’s hyperpigmentation present at birth? Did other signs or symptoms, such as a rash, accompany or precede it? Obtain a history of medical disorders (especially endocrine) as well as contact with or ingestion of chemicals, metals, plants, vegetables, citrus fruits, or perfumes. Is the hyperpigmentation related to exposure to sunlight or a change of season? Is the patient pregnant or taking prescription or over-the-counter drugs?
Explore other signs and symptoms, too. Ask about fatigue, weakness, muscle aches, chills, irritability, fainting, and pruritus. Does the patient have any cardiopulmonary signs or symptoms, such as cough, shortness of breath, or swelling of the ankles, hands, or other areas? Any GI complaints, such as anorexia, nausea, vomiting, weight loss, abdominal pain, diarrhea, constipation, or epigastric fullness? Also, ask about genitourinary signs and symptoms, such as dark or pink urine, increased or decreased urination, menstrual irregularities, and loss of libido.
Next, examine the patient’s skin. Note the color of hyperpigmented areas: Brown suggests excess melanin in the epidermis; slate gray or a bluish tone suggests excess pigment in the dermis. Inspect for other skin changes, too—thickening and leatherlike texture as well as changes in hair distribution. Check the patient’s skin and sclerae for jaundice, and note any spider angiomas, palmar erythema, or purpura.
Take the patient’s vital signs, noting fever, hypotension, or pulse irregularities. Evaluate his general appearance. Does he have exophthalmos or an enlarged jaw, nose, or hands? Palpate for an enlarged thyroid gland, and auscultate for a bruit over the gland. Palpate the muscles for atrophy and the joints for swelling and tenderness. Assess the abdomen for ascites and edema, and palpate and percuss the liver and spleen to evaluate their size and position. Check the male patient for testicular atrophy and gynecomastia.
Medical causes
Acanthosis nigricans
This soft velvety-brown verrucous pigmentation is found most commonly in the skin folds and may have associated skin tags. It typically occurs in individuals younger than age 40, may be genetically inherited, and is associated with obesity or endocrinopathies, such as hypothyroidism or hyperthyroidism, acromegaly, polycystic ovary disease, insulin-resistant diabetes, or Cushing’s disease.
When seen in individuals older than age 40, this disorder is commonly associated with an internal malignancy, usually adenocarcinoma, and most commonly of the GI tract or uterus; less commonly of the lung, prostate, breast, or ovary. Acanthosis nigricans of the oral mucosa or tongue is highly suggestive of a neoplasm, especially of the GI tract. This skin condition commonly regresses with successful treatment of the neoplasm and may recur with reoccurrence of the disease.
Acromegaly
This disorder results from a pituitary tumor that secretes excessive amounts of growth hormone after puberty. Hyperpigmentation (possibly acanthosis nigricans) may affect the face, neck, genitalia, axillae, palmar creases, and new scars. Skin appears oily, sweaty, thick, and leathery, with furrows and ridges formed over the face, neck, and scalp. The tongue is enlarged and furrowed; lips are thick; and the nose is large. Body hair is markedly increased. The hands are broad and spadelike. Marked prognathism interferes with chewing.
Adrenocortical insufficiency (Addison’s disease)
This disorder produces diffuse tan, brown, or bronze-to-black hyperpigmentation of both exposed and unexposed areas of the face, knees, knuckles, elbows, antecubital areas, beltline, palmar creases, lips, gums, tongue, and buccal mucosa (where hyperpigmentation may be bluish black). Normally pigmented areas, moles, and scars become darker. Early in the disorder, hyperpigmentation occurs as persistent tanning after exposure to the sun. Some patients (usually female) lose axillary and pubic hair; about 15% have vitiligo. Patients may develop slowly progressive fatigue, weakness, anorexia, nausea, vomiting, weight loss, orthostatic hypotension, abdominal pain, irritability, weak and irregular pulse, diarrhea or constipation, decreased libido, amenorrhea, syncope and, sometimes, an enhanced sense of taste, smell, and hearing.
Cirrhosis, biliary
Hyperpigmentation is a classic feature of this disorder, which primarily affects women between ages 40 and 60. A widespread and accentuated brown hyperpigmentation appears on areas exposed to sunlight, but not on the mucosa. Pruritus that worsens at bedtime may be the earliest symptom. Fatigue, weight loss, and vague abdominal pain may appear years before the onset of jaundice. Malabsorption may cause nocturnal diarrhea, frothy and bulky stools, weight loss, purpura, and osteomalacia with bone and back pain. The patient may also have hematemesis from esophageal varices, xanthomas and xanthelasmas, hepatosplenomegaly, ascites, edema, spider angiomas, and palmar erythema.
Cirrhosis, Laënnec’s
After about 10 years of excessive alcohol ingestion, progressive liver dysfunction causes diffuse, generalized hyperpigmentation on sun-exposed areas. Early in the disorder, the patient may complain of increasing weakness, fatigue, anorexia, slight weight loss, nausea and vomiting, indigestion, constipation or diarrhea, and a dull abdominal ache. As the disorder progresses, the patient may display major signs and symptoms in every body system resulting from hepatic insufficiency and portal hypertension.
Cushing’s syndrome (hypercortisolism)
Most common in females, this syndrome is caused by excessive levels of adrenocortical hormones or related corticosteroids. In addition to hyperpigmentation, findings include diabetes mellitus, hypertension, left ventricular hypertrophy, capillary fragility, increased susceptibility to infection, decreased resistance to stress, suppressed inflammatory response, muscle weakness, pathologic changes from bone demineralization, gynecomastia in males, and mild virilism and amenorrhea or oligomenorrhea in females.
Hemochromatosis
In this inherited disorder (also called bronzed diabetes), most common in men between ages 40 and 60, early and progressive hyperpigmentation results from melanin (and possibly iron) deposits in the skin. Hyperpigmentation develops as generalized bronzing and metallic gray areas accentuated over sun-exposed areas, genitalia, and scars. Early related effects include weakness, lassitude, weight loss, abdominal pain, loss of libido, and signs of diabetes, such as polydipsia and polyuria. Later, signs of liver and cardiac involvement become prominent.
Malignant melanoma
This form of cancer causes malignant lesions of pigmented skin, commonly moles. Common sites include the head and neck in men, the legs in women, and the back in both men and women exposed to excessive sunlight. Up to 70% of these lesions arise from a preexisting nevus. Metastatic melanoma may produce generalized hyperpigmentation.
The cardinal sign of malignant melanoma is a skin lesion or nevus that enlarges, changes color, becomes inflamed, itches, ulcerates, bleeds, changes texture, or develops an associated halo nevus or vitiligo.
Melasma
This light or dark brown hyperpigmentation occurs on areas exposed to sunlight, most notably on the face, and is associated with use of hormonal contraceptives or pregnancy. Some cases are idiopathic. Lesions are symmetrical and usually involve the cheeks, forehead, and upper lip. When related to pregnancy, the pigmentation may decrease after delivery. Melasma has cosmetic significance only.
Porphyria cutanea tarda
Primarily affecting men between ages 40 and 60, this disorder produces generalized brownish hyperpigmentation on sun-exposed areas and extreme skin fragility (particularly on a bald scalp and on the face and hands). It also causes pink or brownish urine (from porphyrin excretion), anorexia, jaundice, and hepatomegaly.
Scleroderma (progressive systemic sclerosis)
Both localized and systemic scleroderma produce generalized dark brown hyperpigmentation that’s unrelated to sun exposure. Other skin findings include areas of depigmentation and spider angiomas. The patient initially experiences signs and symptoms of Raynaud’s phenomenon—blanching, cyanosis, and erythema of the fingers and toes when exposed to cold or stress, and possible finger shortening, fingertip ulcerations, and gangrene of the fingers and toes. Later findings include pain, stiffness, and swelling of the fingers and joints; skin thickening that progresses to taut, shiny, leathery skin over the entire hands and forearms and then over the upper arms, chest, abdomen, and back; masklike facial skin and a pinched mouth; and, possibly, contractures. Systemic scleroderma also involves the GI, cardiovascular, and other body systems.
Thyrotoxicosis
This disorder can cause hyperpigmentation on the face, neck, genitalia, axillae, and palmar creases as well as in new scars. Other findings include vitiligo; warm, moist skin; erythematous palms; fine scalp hair with premature graying; and Plummer’s nails.
Classic findings of Graves’ disease, the most common form of thyrotoxicosis, include an enlarged thyroid gland, nervousness, heat intolerance, weight loss despite increased appetite, profuse diaphoresis, diarrhea, tremor, and palpitations. Exophthalmos, although characteristic, is absent in many patients.
Tinea versicolor
This benign fungal skin infection produces raised or macular scaly lesions, usually on the upper trunk, neck, and arms, which range from hyperpigmented patches in fair-skinned patients to hypopigmented patches in dark-skinned patients.
Other causes
Arsenic poisoning
Chronic arsenic poisoning can cause diffuse hyperpigmentation with scattered freckle-size areas of normal or depigmented skin. Other features may include weakness, muscle aches, peripheral neuropathy, headache, drowsiness, confusion, seizures, and mucous membrane involvement (conjunctivitis, photophobia, pharyngitis, or an irritating cough).
Drugs
Hyperpigmentation can stem from use of barbiturates; salicylates; chemotherapeutic drugs, such as busulfan, cyclophosphamide, procarbazine, and nitrogen mustard; chlorpromazine; antimalarial drugs, such as hydroxychloroquine; hydantoin; minocycline; metals, such as silver (in argyria) and gold (in chrysiasis); corticotropin; and phenothiazines.
Special considerations
Wood’s lamp, a special ultraviolet light, helps enhance the contrast between normal and hyperpigmented epidermis. A skin biopsy can help confirm the cause of hyperpigmentation.
Hyperpigmentation may persist even after treatment of the underlying disorder or withdrawal of the causative drug. Bleaching creams may not be effective if most of the excess melanin lies in subepidermal skin layers. Over-the-counter bleaching creams tend to be ineffective because they contain less than 2% hydroquinone.
Pediatric pointers
Most moles that are found in children are junctional nevi—flat, well demarcated, brown to black—that can appear anywhere on the skin. Although these lesions are considered benign, recent evidence suggests that some of them may become malignant in later life. Some physicians recommend removal of junctional nevi; others advise regular inspection. Congenital melanocytic nevi present at birth should be removed, especially if large (greater than 20 cm), because they become malignant in about 20% of cases. Some of these lesions may have an increased amount of hair.
Bizarre arrangements of linear or streaky hyperpigmented lesions on a child’s sun-exposed lower legs suggest phytophotodermatitis. Advise parents to protect the child’s skin with long pants and socks. Congenital hyperpigmented lesions include benign mongolian spots and sharply defined or diffuse lesions occurring in such disorders as neurofibromatosis, xeroderma pigmentosum, Albright’s syndrome, Fanconi’s syndrome, Gaucher’s disease, Niemann-Pick disease, Peutz-Jeghers syndrome, phenylketonuria, and Wilson’s disease.
Patient counseling
Advise the patient to use corrective cosmetics, to avoid excessive sun exposure, and to apply a sunscreen or sun blocker such as zinc oxide cream. Advise patients who stop using bleaching agents to continue using sun blockers because rebound hyperpigmentation can occur.
Warn every patient with a benign hyperpigmented area to consult his physician if the lesion’s size, shape, or color changes; this may signal a developing skin cancer.
Book Source Details
- Book Title: Professional Guide to Signs & Symptoms (Fifth Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2006 Lippincott Williams & Wilkins.
Other Book Chapters Related to Hyperpigmentation
Read excerpts from these other book chapters related to Hyperpigmentation:
Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2008 Williams & Wilkins.
More About Causes of Hyperpigmentation
» Next page: Pigmentation Disorders (The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
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