Half and Half Nails in a Healthy Person

Area of Science:

• Dermatology
• Nephrology
• Onychology

Background:

• Lindsay's nails, or half and half nails, were first described in patients with chronic kidney disease.
• This nail condition can also manifest in individuals without underlying pathology.

Observation:

• A 57-year-old patient presented with a 17-year history of half and half nail discoloration affecting all fingernails and toenails.
• The nails exhibited a sharp demarcation between a whitish proximal half and a red-brown distal half, persisting despite nail growth and pressure.
• Extensive laboratory tests, including hematology, biochemistry, urinalysis, thyroid function, and autoimmune markers, were within normal limits. Mycological examinations were negative.

Findings:

• Half and half nails are characterized by a distinct white proximal and red-brown distal nail discoloration, unaffected by pressure or nail growth.
• While commonly associated with chronic kidney disease (20-50% of patients), this onychopathy is also observed in other systemic diseases and healthy individuals.
• Histologically, the white band is attributed to chronic anemia or connective tissue changes, while the brown band results from melanin deposition.

Implications:

• The occurrence of half and half nails in an otherwise healthy individual suggests a potential genetic predisposition.
• Understanding the varied etiology of half and half nails is crucial for accurate diagnosis and patient management.
• Further research into the genetic underpinnings of this condition may elucidate its pathogenesis in healthy populations.