A 3-year-old boy is brought to the emergency department for evaluation of a rash. The rash started on his face yesterday and has since spread to his chest, back, and arms. He has also had a runny nose, dry cough, and fever for the past week. The patient is irritable and uninterested in playing. He has not received vaccinations since age 6 months and takes no medications. A few weeks ago, he went on a camping trip in North Carolina but has not traveled outside the country. Temperature is 40.6 C (105 F), pulse is 130/min, and respirations are 24/min. Examination shows a tired-appearing boy with watery and injected bilateral conjunctivae. Tiny white round lesions are present on the buccal mucosa next to the first and second upper molars. The oropharynx and tonsils are erythematous. Small, soft, mobile lymph nodes are palpated along the anterior and posterior cervical chains. The nontender, blanching rash is shown below. Which of the following is the most likely diagnosis in this patient?

Question

A 3-year-old boy is brought to the emergency department for evaluation of a rash.  The rash started on his face yesterday and has since spread to his chest, back, and arms.  He has also had a runny nose, dry cough, and fever for the past week.  The patient is irritable and uninterested in playing.  He has not received vaccinations since age 6 months and takes no medications.  A few weeks ago, he went on a camping trip in North Carolina but has not traveled outside the country.  Temperature is 40.6 C (105 F), pulse is 130/min, and respirations are 24/min.  Examination shows a tired-appearing boy with watery and injected bilateral conjunctivae.  Tiny white round lesions are present on the buccal mucosa next to the first and second upper molars.  The oropharynx and tonsils are erythematous.  Small, soft, mobile lymph nodes are palpated along the anterior and posterior cervical chains.  The nontender, blanching rash is shown below.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d6c4_2c1d_bc81_87874ace8123_MD0003_00 Measles (rubeola) is an extremely contagious disease that is spread by respiratory droplets. The virus can remain airborne for several hours, and patients can contract it by entering a room that an infected person has already exited (eg, waiting room, day care center). Under-immunized patients, such as this child, are at particularly high risk for infection. This patient has the characteristic prodrome of fever, cough, coryza, and nonpurulent conjunctivitis. Koplik spots, small white lesions found on the buccal mucosa opposite the molars, do not appear in all patients but are pathognomonic of measles and may last several days. After 2-4 days of illness, an erythematous, blanching, maculopapular exanthem characteristically develops on the face and spreads in a cephalocaudal and centrifugal pattern to the rest of the body. The rash subsequently coalesces and may become nonblanching with a dark, reddish-brown color. (Choice A) Adenovirus, which can cause pharyngoconjunctival fever, presents with pharyngitis, nonpurulent conjunctivitis, and fever. Rash and Koplik spots do not occur with adenoviral infection. (Choice B) Erythema infectiosum (fifth disease) is caused by human parvovirus B19. Children develop fever and an erythematous "slapped cheek" rash but not Koplik spots or conjunctivitis. erythematous "slapped cheek" rash (Choice C) Kawasaki disease is characterized by fever for ≥5 days, mucous membrane changes, extremity changes, nonexudative conjunctivitis, cervical lymph node >1.5 cm, and a polymorphous rash. This patient does not meet criteria for Kawasaki disease and has Koplik spots, making measles a more likely diagnosis. Kawasaki disease (Choice E) Fever and conjunctival injection can occur in Rocky Mountain spotted fever, but the rash begins on the distal extremities (including palms/soles) and spreads centripetally. (Choice F) Roseola is caused by human herpes virus 6. In contrast to measles, in which the fever peaks with rash onset, the maculopapular rash in roseola appears as the fever resolves. (Choice G) Rubella presents similarly to measles but is relatively mild (eg, low-grade fever, patient is well-appearing) and shorter in duration. The rubella rash spreads cephalocaudally but does not darken as does measles. This patient has a prolonged, high fever with Koplik spots, which are pathognomonic for measles. rubella rash (Choice H) Scarlet fever is caused by Streptococcus pyogenes and presents with pharyngitis, fever, and an erythematous, sandpaper-like rash. Cough, conjunctivitis, and Koplik spots do not occur in scarlet fever. sandpaper-like rash Educational objective: The prodrome of measles includes fever, cough, coryza, and nonpurulent conjunctivitis. Koplik spots, small white lesions on the buccal mucosa, may also develop and are pathognomonic of measles. Following the prodrome, a maculopapular rash appears on the face and spreads in a cephalocaudal and centrifugal pattern. References: Measles. (http://www.ncbi.nlm.nih.gov/pubmed/21855993)

A 3-Year-Old Boy Is Brought to the Emergency Department for Evaluation