What condition is suggested by a lesion at the corner of the lip?

The presence of a lesion at the corner of the lip is most commonly associated with angular cheilitis. This condition typically manifests as inflamed, fissured lesions at the corners of the mouth, often linked to factors such as nutritional deficiencies, infections, or excessive moisture. Angular cheilitis can result in discomfort and can be exacerbated by conditions that lead to drooling or poor oral hygiene.

While syphilis, squamous cell carcinoma (SCC), and herpes labialis can also present with lesions on or around the lips, the specific location at the corner of the lip, combined with the typical presentation of angular cheilitis, makes it the most likely diagnosis in this case. Syphilis may cause lesions at various locations, including the mouth, but is less specific for this area. SCC generally presents as a more indolent and potentially ulcerative lesion, which is not typically localized to the corners of the lips. Herpes labialis, known for its clustered vesicular lesions, tends to appear on the lips rather than at the corners.

In summary, a lesion at the corner of the lip is most indicative of angular cheilitis due to its characteristic inflammatory appearance, which is directly linked to the specific area affected.