What is the most likely diagnosis for a 79-year-old woman with thin, concave nails that have started curling upward over the past year, presenting for a health maintenance examination?

Differential Diagnosis for Curling Nails

The patient's symptoms of curling nails with a concave appearance can be approached by considering various diagnoses. Here's a categorized differential diagnosis:

• Single most likely diagnosis

  • A. Iron deficiency anemia: This condition is known to cause nail changes, including koilonychia, which is characterized by thin, concave nails that can appear to be curling upward. The patient's age and the gradual onset of symptoms over a year make this a plausible diagnosis.

• Other Likely diagnoses

  • B. Megaloblastic anemia: Although less common than iron deficiency anemia, megaloblastic anemia can also lead to nail changes, including brittleness and alterations in nail shape. However, it is less directly associated with the specific symptom of curling nails compared to iron deficiency.
  • Onychomycosis (D): Fungal infections of the nails can cause thickening and deformation, which might be perceived as curling in some cases. However, onychomycosis typically presents with other signs like nail thickening, discoloration, and sometimes separation from the nail bed.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

  • None of the provided options directly fit into the "do not miss" category as they are not typically associated with immediately life-threatening conditions. However, it's crucial to consider systemic diseases that could lead to similar nail changes, such as:
    • Plummer-Vinson syndrome: A rare condition associated with iron deficiency anemia, characterized by esophageal webs and an increased risk of esophageal cancer. The nail changes are similar to those seen in iron deficiency anemia.
    • Systemic diseases like lupus or sarcoidosis can also cause nail changes, though they would typically be accompanied by other systemic symptoms.

• Rare diagnoses

  • Onycholysis (C) and paronychia (E): These conditions involve the separation of the nail from the nail bed and inflammation of the nail fold, respectively. While they can affect the appearance and health of the nails, they do not typically cause the specific symptom of curling upward.
  • Other rare conditions affecting the nails, such as nail-patella syndrome or hereditary nail dysplasias, could potentially cause abnormal nail shapes but would likely have been present since birth or early life, making them less likely given the patient's age and the recent onset of symptoms.