The primary cause of acne mechanica is prolonged mechanical stress on the skin, which can result from wearing tight clothing, sports gear, helmets, or backpacks. The friction and pressure cause irritation and inflammation of the hair follicles, leading to clogged pores and acne formation. Additionally, heat and sweat trapped under the clothing or gear exacerbate the condition by creating a moist environment conducive to bacterial growth. Understanding these triggers helps in identifying high-risk activities and making necessary adjustments to prevent acne mechanica.