Uncommon symptoms include pulsation and spontaneous bleeding. Most of these are on or near the ear or on the forehead or scalp. The lesions range from erythematous to brown and may be eroded or crusted. The majority of the remainder show grouped papules or nodules in a single region. Rarely, the lesions may be pulsatile.
Larger nodules tend to be deeply centered within the subcutis.
It is uncertain whether it is a neoplastic or reactive state. A reactive cause is favored. The clinical presentation of papules around the ears may suggest ALHE to the alert clinician, but biopsy is required to establish the diagnosis. ALHE shows characteristic histologic features including a proliferation of small blood vessels, many of which are lined by enlarged endothelial cells with uniform ovoid nuclei and intracytoplasmic vacuoles. These distinctive endothelial cells have been described as having a cobblestone appearance.