Eczema and heat rash have clear differences, including different causes. Eczema is primarily caused by allergens, as well as excessive mental stress, anxiety, and hormonal imbalances. Heat rash, on the other hand, usually arises from overly humid and hot environments that affect normal sweating function, leading to blocked sweat ducts. Their clinical manifestations also differ. Eczema typically presents as polymorphic and symmetrically distributed lesions, usually manifesting as papules and vesicular papules, and in severe cases, erosion, exudation, and significant itching are observed. Heat rash clinically appears as tiny, pin-sized blisters that emerge in clusters and merge into patches, typically found at skin folds without symmetry. White heat rash generally has less noticeable itching, whereas red heat rash is itchy and can also feel burning.