21-Year-Old With Heel Lesion

Published on April 1, 2024

Differential Diagnosis

Acral lentiginous melanoma
Atypical nevus
Talon noir
Tinea nigra

Diagnosis

The correct diagnosis is talon noir, also referred to as calcaneal petechiae. Resulting from intraepidermal hemorrhage, this asymptomatic discoloration of acral skin can be caused by shear-force injuries. Talon noir tends to present on the posterior foot, lateral foot, heel, and palm. Lateral shearing forces can cause tearing of blood vessels in the papillary dermis, common in patients who participate in athletic activities. The punctate papillary dermal hemorrhages lead to extravasation of blood into the epidermis and intracorneal retention of hemoglobin. Because of its location in the stratum corneum, it cannot be cleared by phagocytic cells.

What to Look For

The condition is asymptomatic and painless, so patients may not recall specific etiological events
On close dermoscopic exam, band like pigmentation may be present

Pearls for Urgent Care Management

No intervention is required for this condition, it will resolve spontaneously
Resolution may take 4-6 weeks and may require cessation of triggering activity
It is important to distinguish from melanoma by its reddish color, sharply defined borders and segmented band like pigmentation