BOF: 37 (2.30)
A 35-year-old Japanese male presents with anterior
uveitis. There is a history of recurrent oral ulceration and he has also had
ulcers on his scrotum that have resulted in scarring.
To further investigate the patient’s condition a 20 G
needle is inserted into the skin of his forearm. A positive result in this
test is:
a)
A blister appearing at the site if injury in 24-48 hours
b)
A weal appearing at the site of injury immediately
c)
Multiple petechiae appearing at the site of injury within 5 minutes
d)
A papule or pustule appearing at the site of injury within 24-48 hours
e)
An erythematous nodule appearing at the site of injury within 24-48
hours
Answer:
d)
The clinical features suggest that the patient has
Behcet’s disease. In this condition pathergy is often demonstrable. Pathergy refers to an
excessive inflammatory reaction to non-specific injury. In a positive test,
insertion of a 20 G needle into the skin of the forearm results in a papule or
pustule within 24-48 hours.
