Idiopathic acquired true total and subtotal leukonychia: report of two cases

report of two cases Editor, Hereditary leukonychia (milky/white nails) is a rare disorder and may present with either partial or total involvement of the nail. Nail whitening is attributed to the abnormal keratinization of cells derived from the distal nail matrix, which results in numerous intracellular vacuoles with less dense keratins. Cells containing keratohyaline granules reflect light, which results in the white opacification of the nails and the obscuring of the underlying vascular bed. A 20-year-old African man presented with an 8-year history of asymptomatic total leukonychia (TL) involving only the fingernails (Fig. 1a). He reported a total clearing of one or more of the fingernails at different times. There was no medical, family, or drug history of note. Clinical examination revealed chalky, white nails with normal texture, consistent with TL. The rest of the examination revealed no other abnormal mucocutaneous findings nor any associated systemic or congenital abnormalities. Laboratory investigations, including a complete blood count, liver, renal and thyroid profiles, and human immunodeficiency virus (HIV) test, were all normal. The fungal stains and cultures of distal nail clippings were negative. Histopathological examination using hematoxylin and eosin stain showed marked parakeratosis within the nail plate (Fig. 1b). A 12-year-old Caucasian boy presented with total and partial leukonychia (PL) that had affected all nails since birth (Fig. 2). The severity of the nail discoloration had varied over the years, with intermittent partial and total involvement. General and systemic examinations were unremarkable, and the patient had no significant family or drug history. An examination of the patient’s palms, soles, and interdigital areas for fungal infection was negative. Potassium hydroxide (KOH) preparations and Periodic Acid-Schiff (PAS) staining of nail clippings from all nails were negative. Leukonychia describes the partial or complete whitening of the nail plate. In true leukonychia, nail plate whitening is caused by parakeratosis and can be inherited or acquired, whereas in apparent leukonychia, the whitening is caused by nail bed abnormalities and is usually related to trauma. However, it may also occur in arsenic poisoning, typically as banded TL (Mees lines).