Nail changes in non-infectious skin diseases: a narrative review

Purpose: This review summarizes nail changes associated with non-infectious dermatologic diseases and describes these manifestations using appropriate medical terminology. It aims to assist clinicians in recognizing nail alterations, incorporating these findings into the diagnostic evaluation of skin disorders, and improving the management of both nail and cutaneous diseases. Current Concepts: Although nails account for only about 0.1% to 0.2% of the total body surface area, they serve critical functional and protective roles. By reinforcing and safeguarding the distal digits, nails enhance grip strength and fine motor coordination. Structurally composed of hard keratin, similar to hair, the nail unit is designed to support these mechanical functions. When affected by disease, nails may become brittle or thickened and exhibit color changes, such as yellow, white, or black discoloration. These alterations may arise from primary nail disorders or develop secondarily from underlying dermatologic diseases. Discussion and Conclusion: Inflammatory skin conditions such as lichen planus, atopic dermatitis, and psoriasis, as well as connective tissue diseases including lupus erythematosus, systemic sclerosis, and dermatomyositis, may involve the nail unit and produce characteristic changes. Some alterations are disease-specific and aid in diagnosis, whereas others overlap across conditions, requiring clinical correlation with cutaneous findings and histopathologic evaluation for confirmation. Treating the underlying skin disease often leads to improvement in nail changes; however, in some cases, nail abnormalities may persist and require targeted management strategies independent of primary dermatologic therapy.