What are the predisposing factors for miliaria?

The predisposing factors for miliaria (heat rash) mainly include: 1. **High temperature and humidity**: This is the primary cause of miliaria. In hot, humid environments, the body sweats heavily, and sweat does not evaporate easily, leading to maceration and swelling of the stratum corneum. This results in blocked sweat ducts, impaired sweat excretion, and ultimately the development of miliaria. 2. **Wearing non-breathable clothing**: Tight-fitting or synthetic fiber clothing can interfere with normal heat dissipation and sweating, increasing the risk of developing miliaria. 3. **Individual physical differences**: Some individuals are more prone to miliaria in hot environments due to underdeveloped sweat glands or poor sweating function. In addition, infants are a high-risk group for miliaria due to their rapid metabolism, increased sweating, and underdeveloped sweat ducts. 4. **Sudden environmental changes**: For example, moving suddenly from a hot environment to a cooler one can cause pores to close rapidly, forcing sweat back into the skin and potentially triggering miliaria. 5. **Localized skin moisture**: Moist environments promote bacterial growth and intensify the skin's inflammatory response, which can trigger or worsen miliaria.