Psoriasis is often present in obese patients. The severity of psoriasis seems to be connected to the severity of obesity.
The pathway to the establishment of this condition is complex and a result of the interaction of genetic and environmental factors, and the immune response.
Psoriasis and Psoriatic Disease
Psoriasis is often a subset of the wider phenomenon known as "psoriatic disease." Psoriatic disease (PD) refers to a "systemic," i.e "whole body" inflammation issue that affects more than just the skin and joints.
- PD affects the cardiovascular system
- It is involved in bringing about reduced bone density, i.e. osteoporosis.
- It also leads to eye inflammation, intestinal inflammation, and liver disease.
Although psoriasis manifests in the skin, it is often seen to exist side by side with diabetes, metabolic syndrome, and myocardial infarction, in addition to obesity.
Obesity is actually found to be more common in patients having psoriasis alone, rather than those with full-blown PD. Moreover, patients with higher levels of obesity show poorer response to systemic treatments of psoriasis.
The Body Chemistry Of Fatty Tissue
Obesity is characterized by an abundance of adipose; i.e. fatty tissue, in the body. Studies have shown that adipose tissue is the site of several proinflammatory body chemicals, "adipokines" and the classic "cytokines." Adipokines are rather like biochemical messengers, with which the "energy reservoir" that is fatty tissue, communicates with the body.
Adipokines leptin and resistin are seen to be present in high levels in obese persons with psoriasis. Higher their levels in the plasma, the more severe the psoriasis condition.
The link between obesity and psoriasis can be defined thus:
Obesity, through proinflammatory pathways, is a predisposing factor to the development of psoriasis and aggravates existing psoriasis.
Obesity and psoriasis are linked by a common pathophysiological mechanism, which brings about low-grade, chronic inflammation via proinflammatory adipokines that originate in fatty tissue.
Conditions where obesity and psoriatic disease coexist, are part of a complex web that raises more questions than answers:
Are overweight and obesity inbuilt traits of PD itself, or comorbidities?
Is obesity more prevalent in patients with PD because painful, swollen joints make physical activity difficult?
Studies that attempt to understand this chicken-and-egg scenario have shown that:
- There is an association between hypertension and arthritis that started after age 40, and between diabetes and psoriasis as well.
- Most cardiovascular risk factors tend to occur in patients whose psoriasis or arthritis begins after age 40. Yet, psoriasis itself, or arthritis, contributes to increased cardiovascular risk. This is more influential than age and prevails, irrespective of these other factors.
- Obesity is associated with lower retention and response rates to biologic disease-modifying antirheumatic drugs (DMARDs) prescribed to PD patients.
How can cytokines and adipokines help?
Cytokines and adipokines can serve as biomarkers to determine the degree of disease advancement, the level of risk posed by comorbidities, and the success that can be obtained by different treatment options. Certain studies have identified the principal biomarkers that could classify the obesity-psoriasis patient segment as:
- having active disease,
- being in remission, or
- responsive to treatment
But further studies are needed to distill out those biomarkers that can be applied in different clinical scenarios and by physicians with different levels of training.
In general, obesity-psoriatic disease patients should receive special attention to preserve their physical function with anti-inflammatory treatments, and healthy lifestyles should be encouraged.