CASE 84
A 24-year-old man presented to the emergency department with a complaint of a chickenpox-like rash that he noticed the day before. Four days earlier, he had developed the sudden onset of fever, severe headache, and back pain, which were resolving when the rash began.
PHYSICAL EXAMINATION
LABORATORY STUDIES
Diagnostic Work-Up
Table 84-1 lists the likely causes of illness (differential diagnosis). An illness with acute onset of fever higher than 38.3°C followed by a rash characterized by firm, deep-seated vesicles or pustules in the same stage of development without other apparent cause requires immediate investigation. Investigational approach may include
Rationale: There are many causes of vesicular and pustular rash diseases (e.g., varicella, herpes simplex, drug reactions, rick-ettsialpox). The likelihood of reintroduction of smallpox is extremely low. In the unlikely event of an outbreak, it is an extremely important task to first rule out chickenpox. Chicken-pox is more prominent on the trunk and does not usually involve the palms and soles; lesions may appear in crops. Smallpox is more prominent on the face and extremities and often involves the palms and soles. Chickenpox lesions reveal different stages of development. In contrast, smallpox lesions are all at the same stage of development. The other rash diseases, notably rick-ettsialpox and molluscum, can have vesicular lesions and should also be considered. Herpes does not usually disseminate in a normally healthy individual. Drug reactions may be vesicular.