Sweat rash develops as the result of candida (a naturally occurring yeast on found on everyone's skin) reacting to perspiration that's been trapped under the skin, according to the Mayo Clinic. This leads to clogged sweat ducts, which manifest as a rash. There are a number of culprits to explain why perspiration gets trapped instead of naturally evaporating, including:
Sweat rash is more predominant in children and infants, as their sweat glands are still underdeveloped and more prone to rupturing. Newborns who are bundled in too many layers or who experience a high fever are also more susceptible. If this sounds awfully similar to diaper rash, know that diaper rash usually includes very bright red skin with bumps along the outer edges, while sweat rash surfaces as little red bumps or blisters, according to the National Institutes of Health (NIH).
The likelihood of developing sweat rash spikes significantly during warmer seasons, as well as in hot and humid climates.
Whether it's due to heredity, weight, or something else, if you already have a tendency to overheat or excessively sweat, consider yourself more at risk. Intense activities, such as physical labor or exercise, can also lead to this condition. Those who are medically bed-bound for extensive periods sometimes develop excessive sweating as well, especially if they have a fever.
Certain fabrics such as cotton "breathe" more than others like polyester. Wearing something made from a less breathable material can aggravate the condition, particularly if the clothing is tight or damp.
Medications and Creams
As the Mayo Clinic notes, there are some prescriptions, such as Accutane (used to treat acne) and Adriamycin (used in chemotherapy), where heat rash is among the potential side effects. Heavy lotions can also contribute if they block sweat ducts.