BackgroundOxidative stress, the shift in ratio between oxidants and antioxidants, has not been confirmed yet as an etiological factor in acne vulgaris. Objective To detect the evidence of oxidative damage, precisely, in lesions of acne vulgaris of different severity. Patients and methodsThis study was carried out on 30 patients with acne vulgaris, eight males and 22 females, aged between 15 and 25 years, (mean: 19.3 ± 2.11 years) subdivided into four subgroups according to the disease severity: 10 patients with mild acne, 10 with moderate acne, 10 with severe acne, five with very severe acne, and 10 age and sex matched healthy controls. Glutathione peroxidase (GSH-PX) and malondialdehyde (MDA) levels were estimated spectrophotometrically in skin specimens from lesions of acne vulgaris and normal skin of healthy controls. ResultsThere was a high statistically significant decrease (P = 0.001) in GSH-PX enzyme levels in the patients compared with the controls whereas there was a high statistically significant increase (P = 0.006) in MDA levels in patient group compared with control group. There was statistically significant positive correlation between MDA levels and severity of acne vulgaris (r = 0.850, P = 0.0002) and a significant negative correlation between GSH-PX levels and severity of acne vulgaris (r = -0.722, P = 0.0006). In addition, there was a significant negative correlation between MDA and GSH-PX levels in the patient group (r = -0.055, P = 0.0007). ConclusionOxidative stress is evident in lesions of acne vulgaris according to the severity of the disease, which suggests its etiological role in acne vulgaris.