Differential Diagnosis for Vertical Hyperpigmentation of the Thumb Nail in a 1-Year-Old
- Single most likely diagnosis:
- Melanocytic nevus: This is a common benign condition that can cause vertical hyperpigmentation of the nail, especially in children. The presence of a 0.2 cm vertical band of hyperpigmentation is consistent with a melanocytic nevus.
- Other Likely diagnoses:
- Trauma: Trauma to the nail matrix can cause hyperpigmentation, and in a 1-year-old, accidental trauma is a possibility.
- Fungal infection: Fungal infections of the nail can cause changes in nail color, including hyperpigmentation.
- Nutritional deficiencies: Deficiencies in nutrients like vitamin B12 or zinc can cause changes in nail color, including hyperpigmentation.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Subungual melanoma: Although rare in children, subungual melanoma is a potentially deadly condition that can cause vertical hyperpigmentation of the nail. It is essential to consider this diagnosis to ensure prompt treatment if necessary.
- Rare diagnoses:
- Laugier-Hunziker syndrome: This is a rare condition characterized by hyperpigmentation of the nails, lips, and oral mucosa.
- Peutz-Jeghers syndrome: This is a rare genetic disorder that can cause intestinal polyps and hyperpigmentation of the skin and nails.
- Addison's disease: This is a rare endocrine disorder that can cause hyperpigmentation of the skin and nails due to increased levels of adrenocorticotropic hormone (ACTH).