Assessment of interleukin-31 and immunoglobulin E serum levels in psoriasis with and without pruritic symptoms and their correlations with disease severity

Background Interleukin-31 (IL-31) is one of the main cytokines that cause pruritus in a variety of skin conditions. Also, immunoglobulin E (IgE) is one type of immunoglobulin that is necessary for the allergic reaction. There is some evidence to suggest that IgE and IL-31 may be involved in the pathophysiology of psoriasis. Aim To compare the blood levels of IgE and IL-31 in psoriasis patients to controls and determine whether these levels are associated with pruritic symptoms and the severity of the disease. Patients and methods This case–control study included 45 participants; 15 psoriasis patients with pruritus, 15 psoriasis patients without pruritus, and 15 healthy age and sex-matched controls. Psoriasis severity was assessed using the PASI score, and pruritus intensity was assessed using visual analog scale. Results Serum IgE and IL-31 levels were higher in psoriatic patients with pruritus as compared to controls and psoriasis patients without pruritus, with statistically significant differences. The blood IgE level, the duration of the illness, and the PASI score among psoriasis patients with pruritus were substantially associated. The length of the illness and the PASI score in psoriasis patients’ serum IL-31 levels were significantly correlated. Conclusion Patients with psoriasis had significantly higher serum IgE and IL-31 levels than healthy individuals. When comparing psoriasis patients with pruritus to those without, there is a significant increase in serum IL-31. A strong correlation was found between the intensity of pruritus and the severity of the illness and serum IgE and IL-31 levels.