Hispanic skin's three challenges

June 1, 2006

New York - Hispanic skin disorders are, on the whole, verysimilar to those encountered by nonethnic populations, butdeviations do exist.

Three of the most important relate to facial pigmentation, body pigmentation and acanthosis nigricans, Miguel Sanchez, M.D., says.

Dr. Sanchez, an associate professor of dermatology at New York University's School of Medicine, adds, "In most cases, Hispanic patients presenting with facial pigmentation concerns will have melasma."

One study suggests that at least half of Hispanic females will develop visiblemelasma during pregnancy.

Malar and centrofacial presentations are most frequent in all age groups, while mandibular melasma tends to show up later - at an average age of 44, according to a study of Puerto Rican women. Lesions occasionally present in other locations, such as anterior chest, upper back and arms.

Male Hispanics have a much lower incidence and rarely seek medical care for melasma.

Dr. Sanchez says that, after the condition is diagnosed, treatment proceeds along conventional lines - elimination of causative factors, treatment with hypopigmenting agents and photoprotection.

"But if lesions differ from typical melasma, it's worth looking at other options, such as Riehl's melanosis, poikiloderma of Civatte, Berloque dermatitis and friction melanosis. Inflammation is a hint that something else may be going on," he tells Dermatology Times.

That something else can, at times, be obscure. For example, Dr. Sanchez has seen melasma-like reactions to fragrances purchased in other countries and banned in the United States because ingredients induce photosensitivity.

Body pigmentation

The second category in which Hispanic and nonethnic populations deviate is body pigmentation disorders. Of particular note is a higher incidence of erythema dyschromicum perstans (EDP) among Hispanics.

"It's very disfiguring and difficult to treat, unless a patient presents early," Dr. Sanchez explains, "and then systemic or class I topical corticosteroids may have some effect. But generally, by the time a patient arrives, the lesions are well developed."

Dermatologists often diagnose gray patches on the trunk, extremities and neck as EDP. In many cases, it's a misdiagnosis. Other possible and more treatable possibilities include lichen planus pigmentosus, drug eruptions and post-inflammatory hyperpigmentation. Histopathologic findings may point toward additional causes: hyperkeratosis, a thin epidermis, hydropic degeneration of the basal layer, pigment incontinence and perivascular lymphohistiocytic infiltrate.

Folk remedies

For changes in facial and body pigmentation, Hispanics often turn to folk remedies. Aloe vera and lemon juice are popular.

"Lemon juice contains citric acid, an alpha hydroxy acid," Dr. Sanchez notes. "In combination with anti-inflammatory products, it can actually help, especially with melasma."

In other cases, self-treatment may aggravate problems. Some Hispanics favor bleaching creams purchased at specialty stores called "botanicas." Most are imported and some contain mercury, leading to elevated blood levels of the element.

Acanthosis nigricans

Dr. Sanchez says Hispanics from Mexico and Puerto Rico are nearly two times more likely than the general population to get diabetes.

Acanthosis nigricans - velvety plaques, gray-brown to black in color, that usually present in the axillae, neck, anogenital and groin regions - is a marker for insulin resistance and susceptibility to diabetes.

Acanthosis nigricans is particularly common among Mexican-Americans who change from a high-fiber diet to a fast food diet upon arriving in the United States. Often they live in high- crime neighborhoods and make their children stay inside. To amuse themselves, the children watch television or play computer games, and they subsequently gain weight.

Dr. Sanchez says, "Dermatologists need to test for blood sugar levels and counsel patients with acanthosis nigricans about their risk for diabetes and the need to alter their lifestyle."