Deficient serum 25(OH)D levels are present in vitiligo patients with and without systemic autoimmune diseases. Accordingly, screening for vitamin D deficiency seems of value in vitiligo patients for the possibility of vitamin D supplementation.

Oxidative stress exists in patients with acne vulgaris and may play a role in aetiopathogenesis and/or progression of the disease. The addition of drugs with antioxidative effects seems to be valuable in the treatment of acne vulgaris.

Increased lipid peroxidation and defective SOD activity exist in patients with AA. Addition of drugs with antioxidative effects seems to be valuable in treatment.

Serum leptin displays an association with obesity and insulin resistance. Assessment of HOMA-IR in patients with skin tags may serve as a useful approach for diagnosis of insulin resistance. Waist circumference is the only criteria of metabolic syndrome that correlates with number of skin tags.

Patients with metabolic syndrome, with or without AGA, were significantly more insulin resistant compared with patients with AGA with no metabolic syndrome and with healthy subjects and, therefore, no true association exists between AGA and insulin resistance.