Psoriasis may reflect systemic inflammation, heart disease

Consensus is growing that the inflammation that causes psoriatic plaques on the skin also may be a sign of havoc elsewhere in the body.

"It's not just a skin disease," said Neil Korman, MD, PhD, professor of dermatology at Case Western Reserve University in Cleveland.

Viewing this disorder as a systemic disease was the focus of several forums held and studies presented at the American Academy of Dermatology meeting held March 6-10 in San Francisco. One paper from researchers at Harvard Medical School in Boston found that patients with moderate to severe psoriasis had a 28% increased risk of coronary heart disease and a nearly 12% greater risk of stroke.

Another paper reported that those with psoriasis had higher body mass indexes than those with other skin disorders. The higher their weight, the more severe their disease. Those with psoriasis were also more likely to eat poorly.

"The take-home message is patients with psoriasis really need to be screened for cardiovascular disease, diabetes, hypertension and hyperlipidemia," said Jennifer Ahdout, lead author on that paper and a fourth-year medical student at the University of California, Los Angeles.

This meeting is the latest to highlight a burgeoning body of scientific literature, data and expert opinion that psoriasis is related to more than a lower quality of life. Like other inflammatory conditions, it is linked to a shorter lifespan and a range of significant health problems. The theory is that inflammation on the skin may be a reflection or cause of additional inflammation throughout the body.

"For years, it was thought only to be a disease of the skin," said Joel Gelfand, MD, who has published numerous papers and spoke at the AAD meeting on this subject. "In fact, it's an inflammatory disease caused by the immune system, and people with it are more likely to have systemic measures of inflammation."

How this link works is not understood. Many possible explanations are circulating. For instance, patients with psoriasis are more likely to smoke and be sedentary. This circumstance may initiate and accelerate the inflammatory process. But those with this skin problem also have a higher rate of depression, which may lead to more tobacco use and less exercise. Psoriasis also could start the inflammatory process or may be an indication of what is going on inside. To varying degrees, all may be true.

"There may be multiple pathways through which psoriasis could lead to these problems," said Dr. Gelfand, who also is medical director of the clinical studies unit and assistant professor of dermatology at the University of Pennsylvania.

The question also remains regarding how physicians should manage these increased risks. A consensus statement from the editors of the American Journal of Cardiology published in the Dec. 15, 2008, issue said patients should be informed they may have an increased chance of cardiovascular disease. Risk factors should be assessed, and lifestyle interventions and pharmaceuticals prescribed as appropriate. But it's unclear how big a factor this problem should be in deciding what actions to take to protect the cardiovascular system; or whether, like those with diabetes, psoriasis patients should aim for lower blood pressure or cholesterol numbers than the general population.

"Should we be more aggressive in treating risk factors in patients with a chronic inflammatory disease?" said Vincent Friedewald, MD, the statement's lead author and the journal's associate editor. "We don't know the answer ... but it's a good question."

Getting psoriasis patients access to medical care for issues beyond the skin also presents challenges. Patients in their 30s and 40s tend not to have other health problems and see only a dermatologist, who may not be able to address broader issues.

"It's a paradigm shift in words, not yet in practice," said Dr. Korman, who also made a presentation at the AAD meeting.

Patients may be too overwhelmed in caring for their skin to pay attention to their cardiovascular system, and many may not seek any medical care for any reason. Also, although an increasing number of dermatologists are seeing psoriasis as systemic disease, this perspective is not necessarily being embraced by other specialties, including primary care.

"Primary care doctors need to be educated about this risk," said Daniel Federman, MD, a general internist and professor of medicine at Yale School of Medicine in Connecticut. He has published several papers on this topic. "But many patients who have a skin disease, especially if they are relatively healthy, are only seeing a dermatologist. If we can encourage dermatologists to refer to primary care, and primary care physicians to assess vascular risk, that would be great."

Physicians are calling for research to determine if treating psoriasis improves a patient's overall health status or if treating other signs of inflammation, such as cardiovascular risk factors, might improve the skin.

Dr. Gelfand is the principal investigator on a $3.9 million grant from the National Heart, Lung and Blood Institute. He and his team are prospectively following 5,000 psoriasis patients to see if they have a higher prevalence of cardiovascular risk factor, don't control these risks as well and have a higher rate of coronary and vascular events than seen in the general population. This project, which started in March, will also investigate if severity of this skin disorder correlates with heart disease outcomes.

The print version of this content appeared in the April 13, 2009 issue of American Medical News.

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