Neutrophil-to-lymphocyte ratio (NLR) in dermatology perspective: a review

Abstract

The neutrophil-to-lymphocyte ratio (NLR) is the ratio between the number of neutrophils and lymphocytes in the peripheral blood. Neutrophils are responsible for an initial immune response to pathogens that enter the body through the mechanisms of chemotaxis, phagocytosis, the release of reactive oxygen species (ROS), granular proteins, production and release of cytokines. Neutrophils also have an important role in the occurrence of the systemic inflammatory response (SIRS). There are several types of diseases in the field of dermatology that are also related to NLR. It is associated with the presence of an inflammatory process. In addition, NLR is considered an easy, inexpensive, and reproducible parameter associated with clinical outcomes and disease severity. Several diseases in the field of dermatology found to be associated with NLR include leprosy, Stevens-Johnson syndrome/ toxic epidermal necrolysis (SJS/TEN), psoriasis, vitiligo, atopic dermatitis, systemic sclerosis, and skin cancer. In recent years, its role as an independent prognostic factor for neoplasms and as an inflammatory biomarker in various acute and chronic diseases has been increasingly established in the dermatology field. However, not all studies have found significant results. One of them is vitiligo which still finds controversial results. For this reason, this literature review will discuss specifics related to several diseases in dermatology associated with NLR.