Chief Complaint

A 24 y.o. male presents with several "cold sores in my mouth that are killing me!" He says he has had similar outbreaks, starting during his first year in college. The sores typically appear fairly abruptly, lasting for about 3 weeks; this time the sores have been present for about 4 days. They are extremely painful, and he has tried several over-the-counter agents without relief. He thinks that they are herpes related, as he has had similar sores on his scrotum, and he was told in college that it was from herpes; the sores now are often limited to his mouth. He describes his health as generally good, saying he is an avid runner and spends a lot of time outside. He did have an upper respiratory infection about 1 month ago for which he took a 5-day course of antibiotics that "cleared it up." He is a computer programmer and is married. His wife does not have anything similar and has never had similar sores.
Physical Examination

• Vital signs: T 98, BP 118/76, HR 58, RR 30, HT 70, WT 170 lbs.
• General: Well developed and in no acute distress, although reaches up to his mouth when describing his symptoms.
• Ears: Canal intact, TM translucent and bright, landmarks visible.
• Nose: Moist, pink mucosa, no lesions or drainage.
• Face/lips: Skin intact, no lesions on face, one lesion on lower right lip.
• Mouth: Dentition intact, mucosa generally moist, with eight lesions noted. Scattered on inner cheeks/buccal mucosa (two right, three left) tongue (two). Lesions are ulcerative with reddened margins and gray base. Diameters range from 0.8 to 1 cm.
• Throat: Mucosa pink and most, no lesions, swelling, or exudate. Tonsils barely visible.
• Neck: Full ROM, no lymphadenopathy.

Questions

1. What three conditions would be considered in your differential diagnosis, with most likely condition listed first (with rationale)?

2. What further history, further examination, and diagnostic studies are warranted to explore your differential diagnosis?
A. History
B. Physical examination.
C. Diagnostic studies