What is the recurrent cause of 'cold sore' lesions?

The recurrent cause of 'cold sore' lesions is primarily associated with Herpes simplex type 1 (HSV-1). This virus is known for causing oral herpes, which presents itself as sores, blisters, or ulcers around the lips and mouth. Once a person is infected with HSV-1, it remains dormant in the nerve ganglia and can reactivate under certain circumstances such as stress, illness, or exposure to sunlight, leading to the recurrence of cold sores.

In contrast, the other viruses mentioned serve different roles; for example, Variella-zoster virus is responsible for chickenpox and shingles rather than cold sores. Cytomegalovirus is known for causing various diseases, particularly in immunocompromised individuals, and does not typically lead to cold sore lesions. Human papillomavirus is linked to warts and certain cancers, not to the features of herpes infections. Thus, HSV-1 is distinct in its association with recurrent cold sore outbreaks.