An AK is a rough, scaly patch and is typically not tender, whereas CNH is a discrete, smooth nodule defined by its exquisite tenderness on pressure.
A nodular BCC on the ear is typically a pearly papule that may ulcerate but characteristically lacks the intense pain of CNH.
This presents as a hard, rock-like deposit within the skin, much firmer on palpation than the inflamed nodule of CNH.
Chilblains are violaceous, itchy plaques that appear on acral sites in response to cold, a different trigger and morphology than the single, pressure-related nodule of CNH.
A tophus on the ear is a deposit of uric acid crystals, which can be confirmed by finding crystals on aspiration, and is associated with a history of gout.
An SCC on the ear is a firm, indurated, and often ulcerated or crusted nodule that is typically not as exquisitely tender as CNH.
A wart has a verrucous (cauliflower-like) surface, unlike the smooth, dome-shaped nodule of CNH.
