Diseases that cause pimples under the nose include folliculitis, acne, seborrheic dermatitis, and mite dermatitis. 1. Folliculitis: In the case of folliculitis, the infection of bacteria and other microorganisms can cause swelling of the tissues, so the phenomenon of pimples appears. 2. Acne: In the case of acne, the infection by Acinetobacter spp. can lead to damage to the skin, which can lead to the symptoms of acne. 3. Seborrheic dermatitis: In the case of seborrheic dermatitis, acne can occur due to the exuberant secretion of sebum. 4. Mite dermatitis: If mite infection triggers dermatitis, this time there can be a rash, but also the phenomenon of always growing pimples under the nose. Finally, if you have acne under your nose, please seek medical advice.