How to distinguish eczema from heat rash

Eczema and heat rash (miliaria) are two common skin conditions that can be differentiated based on the following aspects: 1. **Cause of disease**: Eczema is primarily caused by various internal and external factors such as allergies, immune dysfunction, and mental stress, leading to skin inflammation. Heat rash, on the other hand, mainly results from blocked sweat pores and impaired sweat drainage in hot and humid environments. 2. **Affected areas**: Eczema can occur on any part of the body, but commonly affects the face, forehead, behind the ears, eyebrows, and extensor surfaces of the skin, and tends to recur frequently. Heat rash primarily appears in skin folds where sweat easily accumulates and evaporates poorly, such as the neck, armpits, and groin. 3. **Skin lesion morphology**: Eczema presents with various morphological changes, including erythema, papules, vesicles, erosion, and exudation, often accompanied by intense itching. Lesions of heat rash are relatively uniform, primarily presenting as small, needle-sized papules or vesicles, densely distributed and possibly coalescing into patches in severe cases. 4. **Seasonality**: Eczema can occur throughout the year without a clear seasonal pattern, whereas heat rash commonly occurs during hot summer months or in hot and humid environments. If in doubt, timely medical consultation is recommended for diagnosis and treatment by a qualified physician.