Psoriasis is a chronic, immune-mediated disease characterized by an accelerated life cycle of skin cells and widespread inflammation. The link between psoriasis and body weight is complex, often creating a self-perpetuating cycle where one condition drives the other. Psoriasis itself does not directly cause weight gain, but the underlying inflammation and the medications used to treat it significantly increase the probability of weight gain. This relationship is bidirectional: the disease can promote weight gain, and excess weight can simultaneously worsen the skin condition.
The Role of Chronic Inflammation in Weight Changes
Psoriasis is a systemic inflammatory disorder, leading to a constant state of low-grade inflammation throughout the body. Immune cells involved in psoriatic lesions release pro-inflammatory signaling molecules, known as cytokines, into the bloodstream. These circulating cytokines, particularly tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), drive the metabolic dysfunction associated with the disease.
These inflammatory molecules interfere directly with the body’s ability to regulate energy and metabolism. They disrupt the signaling pathways for insulin, leading to insulin resistance in peripheral tissues. This resistance causes cells to struggle to absorb glucose, prompting the pancreas to produce more insulin, which promotes fat storage.
Chronic inflammation also promotes the creation of new fat cells, a process called adipogenesis. The constant presence of inflammatory cytokines shifts metabolic processes toward storing energy rather than burning it efficiently. This metabolic dysfunction makes it more likely for individuals with moderate to severe psoriasis to gain weight and develop conditions like metabolic syndrome, even if their diet or activity level remains stable.
How Excess Weight Influences Psoriasis Activity
While psoriasis-related inflammation can lead to weight gain, obesity fuels the disease in return. Adipose tissue, or body fat, is not a passive storage site; it functions as an active endocrine organ. This tissue releases its own inflammatory molecules, called adipokines, which contribute to a secondary state of inflammation.
Obesity is characterized by an increase in pro-inflammatory adipokines like leptin and resistin, and a decrease in the anti-inflammatory molecule adiponectin. Leptin, which is elevated in obese individuals, promotes the activation of immune cells involved in the psoriatic process. This influx of inflammatory signals from the fat tissue intensifies existing psoriatic inflammation, leading to more frequent and severe skin flares.
This heightened inflammatory environment can increase the total body surface area affected by psoriasis and may even trigger the initial onset of the disease in genetically predisposed individuals. Obesity also complicates treatment because the increased volume of fat tissue can alter how systemic therapies are distributed, leading to lower response rates and making the disease more difficult to control effectively.
Psoriasis Treatments and Their Effect on Metabolism
Certain medications used to manage moderate to severe psoriasis can directly contribute to weight gain through pharmacological side effects. High-dose oral corticosteroids, such as prednisone, are known for their metabolic effects, even when used short-term. These synthetic hormones increase appetite, leading to higher caloric intake, and cause the body to retain salt and water, resulting in fluid retention.
Corticosteroids also cause fat redistribution, promoting deposits in areas like the face, neck, and abdomen, often leading to a characteristic change in body shape. Cyclosporine, another systemic immunosuppressant, is associated with weight gain, primarily through fluid retention and impacts on kidney function and blood pressure regulation.
The newer class of targeted therapies, known as biologics, presents a nuanced picture. Some anti-TNF-alpha inhibitors and IL-12/23 inhibitors have been linked to a modest weight increase. While this gain may reflect improved overall health and a reduction in the inflammatory burden, the effect is variable. Some studies identify this weight increase as an independent factor for weight gain, particularly in men.
Lifestyle Adjustments for Weight Management
Adopting strategic lifestyle changes helps mitigate weight gain and reduce the systemic inflammation associated with psoriasis. Dietary changes focused on reducing inflammation are beneficial, often following the principles of the Mediterranean diet. This eating pattern emphasizes fish rich in omega-3 fatty acids, fruits, vegetables, legumes, and whole grains.
The diet uses extra virgin olive oil as the primary source of fat, while limiting red meat and highly processed foods. This supports weight management and provides anti-oxidant benefits. These components help reduce oxidative stress and modulate the inflammatory pathways that drive both psoriasis and metabolic dysfunction.
Regular physical activity is recommended, but psoriatic arthritis often necessitates a focus on low-impact exercise. Activities such as walking, swimming, cycling, and gentle forms of yoga or Tai Chi are excellent choices. Water-based exercises are beneficial because the buoyancy reduces strain on painful or stiff joints while building muscle strength and endurance.