ABSTRACT
When faced with a rash, the diagnosis is often unclear, and it may be necessary to describe it to someone on the phone for further advice. In this situation, the student must know how to describe the rash in a methodical way:
• Distribution: which parts of the body are affected? • Appearance of individual lesions:
• Macule: a completely flat lesion. • Papule: a raised lesion. A maculopapular rash is the most common type of rash,
containing both macules and papules. • Vesicle: a small lesion (<5 mm diameter) containing clear fluid. • Bulla: a large lesion (>5 mm diameter) containing clear fluid. • Pustule: a pus-filled lesion. • Plaque: a flat-topped lesion.
