Nasal cold sores are typically caused by the herpes simplex virus type one, according to WebMD. The virus can also develop from allergies, colds, fever, stress or certain foods. However, sometimes, nasal cold sores develop as a result of menstruation or sunburn.
The herpes simplex virus type one is transmitted when people are exposed to the virus from an infected individual and share towels, razors, utensils or saliva, according to WebMD. Nasal cold sores trigger sensitivity and itching at the site of the sore and a small bump or blister on the skin or inside the nose.
Nasal cold sores may not require treatment and typically heal on their own within a week or two, according to KidsHealth. Cold sores are more common on and inside the mouth but can develop within the nasal passages. The virus may produce additional symptoms such as swollen neck glands, muscle aches, fever and irritability. Some patients experience tingling or numbness near the sore before a blister appears on the skin or inside the nose.
The virus remains in the body even after the sores are dormant. Nasal cold sores can reactivate, and are often triggered by cold weather, sunlight, fever, infections or stress.