One of the doubts I have received most is regarding the differential diagnosis between canker sores and cold sores. Herpes and canker sores are very different lesions, but in some cases they can cause some confusion.
In this text we will point out only the differences between canker sores and cold sores, showing some photos of lesions to facilitate understanding.
The first major difference lies in the fact that cold sores are an infectious and contagious disease caused by the Herpes simplex virus, while the cold sore is neither an infection nor contagious.
The cold sore is a very painful, ulcer-like lesion that always occurs inside the oral cavity. This is a good tip, the sore appears inside the mouth, at most in the innermost region of the lips; is a wound that can only be seen if the patient opens his mouth or uses his fingers to lower his lips. Conversely, the herpes lesion occurs on the outside of the lips, often reaching the skin around the mouth. While the cold sore is hidden, herpes can be seen by everyone.
While the cold sore is an ulcer, usually with well-delimited edges and a shallower, greyish central area, cold sores start as small bubbles that burst and form crusts after a few days. In herpes, the center is higher than the edges, at the edge the edges are higher than the center. Canker sores usually are oval or rounded, since Herpes usually has a more irregular shape.
In the case of herpes, 6 to 48 hours before the lesions appear, the patient begins to feel a nuisance or a tingle in the affected region. As it is a disease that goes back and forth, most herpes patients know how to identify in advance when an injury will arise. The cold sore, if not caused by a trauma, comes without warning, starting as a small injury that grows over the days.
Herpes may be accompanied by fever, especially on its first appearance after the patient has been infected. The presence of lymph nodes in the neck is more common in herpes, but can also occur in canker sores, especially those of larger size.