Acne mechanica is an acneiform eruption that has been observed after repetitive physical trauma to the skin such as rubbing, occurring from clothing (belts and straps) or sports equipment (football helmets and shoulder pads). : 499   In addition to those mechanisms, the skin not getting enough exposure to air also contributes to the formation of acne mechanica. It is often mistaken as a rash that forms on sweaty skin that is constantly being rubbed, but in reality, it is a breakout of acne mechanica. The term "acne" itself describes the occurrence in which hair follicles (also known as pores) in the skin get clogged by oil, dead skin cells, dirt and bacteria, or cosmetic products and create a pimple. Pimples can vary in type, size, and shape, but the sole basis of them occurring is the same - the oil gland in the pore becomes clogged and sometimes infected, which creates pus in order to fight the infection and subsequently causes the development of swollen, red lesions on the skin. Signs and symptoms
The signs and symptoms at an early stage are harder to be seen. At first look, acne mechanica seems very similar to any other type of acne. However, it differs in how it is caused. A lot of acne has to do with hormones, the amount of oil production in the skin, and genetic predispositions. Acne mechanica specifically refers to the skin irritation that is formed by excess pressure, heat, and rubbing against the skin.
Styes normally heal on their own by rupturing within a few days to a week causing the relief of symptoms, but if it does not improve or it worsens within two weeks, a doctors opinion should be sought. Few people require surgery as part of stye treatment. With adequate treatment, styes tend to heal quickly and without complications. The prognosis is better if one does not attempt to squeeze or puncture the stye, as infection may spread to adjacent tissues. Also, patients are recommended to call a doctor if they encounter problems with vision, the eyelid bump becomes very painful, the stye bleeds or reoccurs, or the eyelid or eyes becomes red. Etymology
The word stye  (first recorded in the 17th century) is probably a back-formation from styany (first recorded in the 15th century), which in turn comes from styan plus eye, the former of which in turn comes from the old English stīġend, meaning "riser", from the verb stīgan, "to rise". The older form styan is still used in Ulster Scots today. The homonym sty found in the combination pigsty has a slightly different origin, namely it comes from the Old English stiġ-fearh—fearh (farrow) is the Old English word for "piglet"—where stiġ meant "hall" (cf. steward), possibly an early Old Norse loanword, which could be cognate with the word stīgan above.The synonymous late Latin expression is hordeolum a modulation of the word hordeolus simply related to hordeum ("barley"), after its resemblance to a barleycorn.