Central Sensitization Affects 1 in 10 Patients With Psoriasis

Central sensitization (CS), characterized by a disparate response to pain stimuli, is linked with conditions that manifest chronic pain, such as rheumatoid arthritis, psoriatic arthritis (PsA), and fibromyalgia, explains Francesco Bellinato, MD. “However, in patients with plaque psoriasis, CS has never been investigated,” he says.

“Chronic inflammation associated with psoriasis might increase CS because it provides a constant and chronic stimulus to skin nerve fibers, whereby patients may become more sensitive to pain,” he says. “In addition to pain, patients with psoriasis may complain of other skin-related symptoms such as pruritus and burning. In addition, anxiety and depression, which are common in patients with psoriasis, can also increase the pain threshold. While the association of PsA with musculoskeletal pain is easily explained, pain experienced by patients with psoriatic skin lesions may be less apparent.”

For a study published in Dermatology and Therapy, Dr. Bellinato and colleagues sought to examine CS in patients with chronic plaque psoriasis and to what extent CS correlated with disease severity, HRQOL, and comorbidities.

CS Affected 10% of Patients With Psoriasis in the Study

The researchers conducted a cross-sectional, observational study of adult patients with moderate to severe psoriasis who consecutively attended an outpatient clinic. A total of 194 patients were included in the study, which was composed of 59% men with a mean age of 54±13. They administered four different validated questionnaires: Central Sensibilization Inventory (CSI), Dermatology Life Quality Index (DLQI), General Anxiety Disorder-7 (GAD-7), and Patient Health Questionnaire-9 (PHQ-9).

The main finding observed by the study team was that CS affects 10% of patients with psoriasis (a CSI score of ≥40). “Higher scores of CSI were associated with psoriasis severity, poor DLQI, concomitant psoriatic arthritis, and symptoms of anxiety and depression,” Dr. Bellinato says, adding that CS may explain generalized, vague painful symptoms that some patients with psoriasis may report without finding any objective clinical confirmation.

Researchers Need to Investigate Biologic Treatments for CS

In the study sample, the proportion of CS was higher in patients with PsA, compared with psoriasis (71% vs 7%, P=0.031). Consistently, the study team noted that patients with PsA have higher mean scores of CSI, compared with psoriasis (27.5±13.5 vs 20.7±13.7, P=0.002), whereas DLQI impairment, PHQ-9, and GAD-7 were similar between the two groups (Table). Dr. Bellinato and colleagues noted that patients with CS often have a history of unsuccessful medical treatments to nonsteroidal anti- inflammatory drug; they are often more responsive to antidepressant and antiepileptic medication. “CS has been proposed as the root etiology for central sensitivity syndromes, which refer to a group of disorders for which no organic cause can be found, including fibromyalgia, chronic fatigue syndrome, and irritable bowel syndrome,” the study authors wrote.

“As CS affects 10% of patients with psoriasis, it’s important for clinicians to investigate it in their practices, particularly in cases of generalized, indefinite painful symptoms,” Dr. Bellinato says. “Whether, and to what extent, systemic or topical therapies can modulate CS needs investigation as well. In particular, the effect of biological treatment on CS is a field of research that deserves our attention.”