What are the differences between heat rash and eczema?

Heat rash and eczema differ in several aspects. 1. In terms of etiology, heat rash is primarily caused by blocked sweat ducts due to poor evaporation of sweat in hot and humid environments. It commonly occurs in summer and affects children and long-term bedridden patients with underdeveloped or impaired sweating mechanisms. In contrast, eczema may be triggered by multiple factors, such as immune dysfunction, nutritional deficiencies, environmental temperature changes, sun exposure, and allergies. It can occur in any season. 2. Regarding affected body sites, heat rash typically develops on areas prone to sweating and friction, such as the forehead, neck, chest, and back. Eczema, however, can occur on any part of the body, but is more commonly found on the lower legs, forearms, ears, hands, and feet. 3. Clinically, the two conditions also present differently. Heat rash mainly manifests as small, red papules or papulovesicles resembling the size of a pinhead, accompanied by itching and a burning sensation; severe cases may present with pustules. Eczema, on the other hand, is characterized by polymorphic skin lesions, including erythema, papules, and vesicles, often accompanied by intense itching. It tends to recur easily.