Which of the following rashes is known to start on palms and soles?

Rocky Mountain Spotted Fever is characterized by a rash that often begins on the palms and soles. This rash typically develops after the onset of fever and headache in patients with the infection caused by Rickettsia rickettsii, transmitted through ticks. The rash can also spread to the trunk and extremities as the disease progresses.

In contrast, psoriasis typically presents as well-defined red plaques with silvery scales, usually affecting the extensor surfaces and the scalp rather than the palms and soles. Atopic dermatitis is more common in flexural areas and is characterized by dry, itchy patches that may not specifically start on the palms or soles. Urticaria, or hives, presents as raised, itchy welts that can occur anywhere on the body and do not have a predilection for the palms or soles. Understanding the specific presentations and common locations of these various dermatological conditions helps to differentiate them in clinical practice.