Serum level of the neuropeptide substance 'P' in patients with acne vulgaris

Background Acne vulgaris is a very common chronic inflammatory disease of pilosebaceous units affecting up to 80% of adolescents with complex pathogenesis. Substance P (SP) is a neuropeptide that is secreted from the terminal ends of special sensory nerves, acts as a neurotransmitter, and is involved in inflammatory processes and pain. Various studies have proved that the inflammatory process within the pilosebaceous unit is modulated by neuropeptides, especially SP. Objective The aim of this study was to evaluate the correlation between SP level and severity of acne. Patients and methods SP levels were estimated in 45 patients with acne vulgaris (AV) and 35 age-matched and sex-matched controls, with exclusion of patients who were taking anxiolytics, antipsychotics, or related drugs within the last year, present or past medical history of isotretinoin or hormonal therapy within the last 3 months, patients on systemic antibiotic for at least 3 months before the study, and patients with any neurological or psychiatric diseases such as mood disorders, major depressive disorder, and anxiety disorders. SP level was detected quantitatively by enzyme-linked immunosorbent assay method. Results SP level was significantly higher in the acne group vs the control group (P<0.001). SP level was highest in the severe acne group, followed by the moderate group and lastly the mild group. SP level was higher in the smoker group vs the nonsmoker group, with a statistically significant difference (P<0.05). Conclusion There was a statistically significant relation between acne severity and the serum levels of SP.