Leukonychia: What Can White Nails Tell Us?

Abstract

Changes in nail color can provide important clues of underlying systemic and skin disease. In particular, white discoloration (leukonychia) has a high prevalence with a wide array of potential relevant causes, from simple manicure habits to life-threatening liver or kidney failure. Therefore, a reliable assessment of the patient with leukonychia is essential. In the past, two classifications for leukonychia have been presented. The morphological classifies the nail according to the distribution of the white lines: total, partial, transversal, and longitudinal leukonychia. Mees' and Muehrcke's lines are examples of transversal leukonychia, while Terry's and Lindsay's nails are examples of total and partial leukonychia. The anatomical classifies according to the structure responsible for the white color: the nail plate in true leukonychia, the nail bed in apparent leukonychia, and the surface only in pseudoleukonychia. In this review, both morphological and anatomical features have been combined in an algorithm that enables clinicians to approach leukonychia efficiently and effectively.

Fig. 1

Trauma-induced punctate true leukonychia

Fig. 2

Pseudoleukonychia caused by superficial white onychomycosis

Fig. 3

Pseudoleukonychia and nail fragility induced by nail cosmetics

Fig. 4

Punctate pseudoleukonychia caused by nail cosmetics (granulation)

Fig. 5

Transversal true leukonychia caused by traumatic manicure.

Fig. 6

Trauma-induced transversal true leukonychia caused by matrix damage due to axial pressure on too long toenails

Fig. 7

Systemic lupus erythematosus-induced transversal true leukonychia

Fig. 8

Transversal apparent leukonychia, Muehrcke’s lines

Fig. 9

In Darier disease, longitudinal true leukonychia is associated with erythronychia (candy cane nails)

Fig. 10

Longitudinal true leukonychia in onychomatricoma

Fig. 11

Idiopathic true leukonychia with porcelain white nails

Fig. 12

Half-and-half nails (Lindsay’s nails) in a patient with chronic kidney disease

Fig. 13

Terry’s nails are characterized by subtotal apparent leukonychia with a reddish or brown distal band of less than 20%

Fig. 14

Algorithm to approach leukonychia. PSO proximal subungual onychomycosis, WSO white superficial onychomycosis

Fig. 15

Dermoscopy of punctate true pseudoleukonychia of the same patient as in Fig. 3

Fig. 16

Dermoscopy of punctate true pseudoleukonychia in superficial white onychomycosis

Fig. 17

In Darier disease, dermoscopy shows alternating parallel longitudinal red streaks with thinning of the corresponding nail plate and white bands