When Patients Present With Leukonychia

The first time I encountered white toenails, I was on my vascular surgery rotation. A patient had toenails and fingernails that demonstrated a chalky white appearance throughout the entirety of the nail plate. The patient questioned me, asking if I knew what caused his nails to turn white. At the time, I did not know and was baffled by the strange appearance of the nails.

Leukonychia is a white discoloration to the nail plate. It generally presents in one of four ways: total leukonychia, partial leukonychia, striate leukonychia or punctate leukonychia.¹ The most common form is punctate leukonychia, in which one or more small white spots appear on the nails. These often result from trauma to the nail, such as smashing or dropping something on the nail, or nail biting.¹ We can further divide leukonychia into its “true” form, in which there is involvement of the nail plate, or its “apparent” form, in which the subungual tissue causes the white appearance.²

The hypothesis is that leukonychia results from abnormal keratinization of the nail plate, emanating in the accumulation of parakeratotic cells. This accumulation, coupled with enlarged keratohyalin granules, allows the reflection of solar light, creating the white appearance of the nail.

Leukonychia is associated with a plethora of various conditions and syndromes. Mees’ lines, horizontal whitened bands across the nail, may result from heavy metal poisoning, cirrhosis, HIV or chemotherapeutic drugs.¹ Half-and-half nails present with a longitudinal band of whitening, typically involving half the nail. This is common with chronic kidney disease, Crohn’s disease and Behçet’s disease.³

Leukonychia totalis, whitening of the entire nail, often results from an autosomal dominant or hereditary recessive disorder, presenting early in childhood.^1,3 Treatment involves identifying and treating the underlying condition resulting in the white discoloration.

References

1. Das A, Bandyopadhyay D, Podder I. Idiopathic acquired true leukonychia totalis. Indian J Dermatol. 2016; 61(1):127.
2. Bakry OA, Attia AM, Shehata WA. Idiopathic acquired true leukonychia totalis. Pediatr Dermatol. 2014; 31(3):404-405.
3. Wollina U, Bula P. Longitudinal ‘half-and-half nails' or true leukonychia." Skin Appendage Disorders. 2016; 1(4):185-186.