###Human: What is causing pimples on the back and shoulders? ###Assistant: Hi. Acne occurs not only on the face but also on the upper back and chest. It is usually due to the hormonal activity over the oil glands of the body. Your pictures (attachment removed to protect patient identity) are suggestive of a combination of truncal acne and Pityrosporum folliculitis. This could be due to your young age, tight clothing, excessive sweating, humid climate, foods with high glycemic index and improper hygiene. Truncal acne or Pityrosporum folliculitis. 1. Acnil soap for bath. 2. Ketoconazole lotion (Kevon stay on lotion or KZ lotion) in the morning after bath. 3. Benzoyl peroxide gel (Persol forte cream) at night. Decrease foods with high glycemic index, take bath daily, avoid tight-fitting clothes.