Pertussis: a reemerging infection.

Pertussis, also known as whooping cough, is an acute respiratory tract infection that has increased in incidence in recent years. The initial catarrhal stage presents with nonspecific symptoms of malaise, rhinorrhea, sneezing, lacrimation, and mild cough. During the paroxysmal stage, severe outbreaks of coughing often lead to the classic high-pitched whooping sound patients make when gasping for breath. The paroxysmal stage is followed by the convalescent stage and resolution of symptoms. Complications vary by age, with infants more likely to experience severe complications such as apnea, pneumonia, seizures, or death. In adolescents and adults, complications are the result of chronic cough. The diagnosis depends on clinical signs and laboratory testing. Both culture and polymerase chain reaction testing can be used to confirm the diagnosis; serologic testing is not standardized or routinely recommended. Although antibiotics have not shown clear effectiveness in the treatment of pertussis, they eradicate nasal bacterial carriage and may reduce transmission rates. Macrolide antibiotics such as azithromycin are first-line treatments to prevent transmission; trimethoprim/sulfamethoxazole is an alternative in cases of allergy or intolerance to macrolides. Immunization against pertussis is essential for disease prevention. Current recommendations in the United States consist of administering five doses of the diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine to children before seven years of age, and administering a tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) booster between 11 and 18 years of age. Recent efforts have focused on the vaccination of adolescents and adults, with new recommendations for a single dose of the Tdap booster if it has not been previously administered.