What skin condition is characterized by U-shaped redness in the neck?

Poikiloderma of Civatte is characterized by a distinctive pattern of skin changes, often seen as U-shaped redness around the neck area. This condition typically occurs due to sun damage and aging, resulting in a blend of atrophy, telangiectasias, and pigmentation changes. The U-shaped appearance is significant because it highlights the areas commonly affected by sun exposure, which is a key aspect in identifying this condition.

In contrast, rosacea often presents with central facial redness and may include acne-like breakouts, but it does not typically feature the U-shaped pattern. Eczema can cause redness and inflammation but does not have the specific distribution or appearance seen in poikiloderma. Keratosis refers to conditions involving thickening of the skin, such as actinic keratosis or seborrheic keratosis, but again, these do not present with a U-shaped redness characteristic of poikiloderma of Civatte. Therefore, identifying U-shaped redness in the neck specifically points to poikiloderma of Civatte.