519. A 5-year-old child develops a febrile disease with cough, a blotchy rash, and cervical and axillary lymphadenopathy. Also noted is an erythematous, maculopapular rash behind the ears and along the hairline, involving the neck and, to a lesser extent, the trunk. Examination of this patient's oropharynx would likely reveal which of the following lesions?

 A.  Adherent thin, whitish patch on gingiva 
 B.  Cold sores on the lips 
 C.  Curdy white material overlying an erythematous base on the oral mucosa 
 D.  Large shallow ulcers on the oral mucosa 
 E.  Multiple small white spots on the buccal mucosa 


The correct answer is E. The disease described is measles (rubeola), which has the typical
presentation described in the question stem. Measles is caused by a Morbillivirus, an RNA virus
belonging to the Paramyxovirus family. Koplik's  spots, which are pathognomonic for measles, are
small, bluish-white spots on the buccal mucosa in the early stages of measles. These lesions appear
just before the onset of the characteristic rash which is a brick red irregular maculopapular rash that
onsets 3-4 days after the onset of the prodrome (which can also involve the extremities) and fade as
the rash develops. This is usually a prodrome of fever, coryza, cough, conjunctivitis, malaise, irritibility
and photophobia as well as koplik's spots. Leukoplakia is a premalignant condition characterized by
adherent whitish patches on the gingiva (choice A) and other sites in the oral cavity. Histologically,
they are similar to hyperkeratoses. Cold sores of the lips (choice B) are due to infection with herpes
viruses. Candida infection (thrush) produces curdy white material loosely attached to an erythematous
base (choice C). When removed there is typically a painful lesion that may bleed. Aphthous ulcers
are large shallow ulcers of the oral mucosa (choice D), commonly known as canker sores. No
systemic involvement is seen