Credit: Brand New Images Stone Getty Images. The Lupus Foundation of America explains that sores inside the nose are a common symptom of lupus, an autoimmune disease. Sores in the nose due to lupus are referred to as mucosal ulcerations and can also be found in the mouth and in vaginal tissue lining. In most cases, lupus ulcers do not cause pain and can resemble cold sores. According to WebMD, sores around the nose are a symptom if impetigo, a condition that is common in children.