Obesity brings risk for plethora of skin conditions

Skin & Allergy News, April, 2008 by Sharon Worcester

SAN ANTONIO -- Obese patients are at increased risk for a number of dermatologic conditions.

It is important for dermatologists to be aware of the increased risk for these conditions among obese patients (body mass index of 30 kg/[m.sup.2] or greater) and morbidly obese patients (BMI of 40 kg/[m.sup.2] or greater) and to inform their patients, Dr. Gil Yosipovitch said at the annual meeting of the American Academy of Dermatology.

Acanthosis nigricans is one such condition, said Dr. Yosipovitch of Wake Forest University in Winston-Salem, N.C.

This condition frequently affects the neck and back, but it can also involve the elbows, knuckles, and face. Take care to avoid mistaking this for melasma or contact dermatitis, he advised.

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Skin tags are common with acanthosis nigricans, as well as in obesity in general and with diabetes; they may serve as a clue to the diagnosis.

Other than weight loss, which can lead to improvement in the acanthosis nigricans and other obesity-related skin diseases, treatment with metformin or topical retinoids may help. There is, however, no magic bullet for this condition in obese patients, he said.

Keratosis pilaris also tends to be associated with increased BMI, as well as with atopy and dry skin (which itself is common in morbid obesity). The increased risk of keratosis pilaris in obese patients is something that many dermatologists are unaware of, but, like acanthosis nigricans, it has been linked with insulin resistance. In a recent study, it was shown to be one of the most common manifestations of insulin resistance, he said.

Striae distensae also are common in obese patients, typically affecting the breasts, buttocks, and thighs. One patient was referred to Dr. Yosipovitch because of concern that the stretch marks were a manifestation of Cushing's disease.

A much rarer but important potential dermatologic complication in obesity is Dercum's disease, which usually occurs in later adult life and involves development of multiple painful lipomas. The disease often is associated with other systemic symptoms, such as weakness, and may also be associated with mental disturbances.

The etiology of this condition is unknown, but magnetic resonance imaging and ultrasound, as well as biopsy, can aid in diagnosis.

"The problem is with treatment," Dr. Yosipovitch said, adding that it is "basically ineffective in most cases."

It has been suggested that surgical excision of painful lipomas is effective. Liposuction, corticosteroid injections, and intravenous lidocaine also have been used with some beneficial effects, he said.

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Other dermatologic diseases may be aggravated by obesity. An example is chronic venous insufficiency, which can lead to a host of problems from lymphedema to venous ulceration.

Psoriasis, plantar hyperkeratosis, tinea pedis, and fungal and bacterial infections also have been linked with obesity, Dr. Yosipovitch said.

A particular concern is necrotizing fasciitis. A recent French study showed that 88% of women hospitalized for necrotizing fasciitis are obese, and data suggest that obesity, diabetes, hypertension, and advanced age predict 50% of mortality in those with the condition.

Other infectious processes are also of concern. Folliculitis has been linked with obesity, and multidrug resistant staphylococcal infection is a common cause of folliculitis. Promote the use of antiseptic and antibiotic creams as appropriate, and if infection is suspected, consider oral antibiotics, he said.

When it comes to treating obese patients with these and other skin manifestations of obesity, don't hesitate to recommend weight loss as part of the treatment, Dr. Yosipovitch said, even though the father of one young patient threatened to sue him for insulting his daughter by advising weight loss.

"This is not just a skin problem. The skin is a window to show some of the internal problems associated with obesity," he said.

In all obese patients, be sure to emphasize good skin care with gentle cleansers. In morbidly obese patients with significant skin manifestations, consider working in close conjunction with the patient's primary care physician and perhaps an endocrinologist to help the patient achieve the best possible outcome, Dr. Yosipovitch suggested.

BY SHARON WORCESTER

Southeast Bureau