Treatment of pertussis is azithromycin, 500 milligrams PO on day 1 and 250 milligrams PO on days 2 to 5.

Trimethoprim-sulfamethoxazole, 160 milligrams/800 milligrams twice a day for 14 days (check renal dosing), is an alternative to those allergic to, or unable to tolerate, macrolides.

Treatment is best if started early, in the first week. After that, antibiotic treatment does not alter the duration of cough.

Chemoprophylaxis is typically given for household contacts, although the evidence base for such treatment is weak.


Whooping cough (pertussis) is a highly contagious respiratory tract infection. In many people, it's marked by a severe hacking cough followed by a high-pitched intake of breath that sounds like "whoop."

Before the vaccine was developed, whooping cough was considered a childhood disease. Now whooping cough primarily affects children too young to have completed the full course of vaccinations and teenagers and adults whose immunity has faded.

Deaths associated with whooping cough are rare but most commonly occur in infants. That's why it's so important for pregnant women — and other people who will have close contact with an infant — to be vaccinated against whooping cough.


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 A 3-year-old girl presents to the emergency department with fever, hoarseness, a “seal bark–like” cough, and inspiratory stridor. Her father states that she has had a cold for the past few days, with runny nose, nasal congestion, sore throat, and cough. He is now concerned because her cough has become loud, harsh, and brassy. Which of the following is the most likely cause of her ailment?


    A. Fungus


    B. Gram-negative bacteria


    C. Gram-positive bacteria


    D. Parasite


    E. Virus

1. The answer is E. This is a classic case of acute laryngotracheobronchitis (croup), an acute inflammation of the larynx, trachea, and epiglottis. The most common cause of croup is a viral (parainfluenza virus type I) infection. 


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