staccato cough

Neonatal chlamydial infection is acquired during passage through an infected birth canal. It produces two distinct syndromes with characteristic timing: inclusion conjunctivitis at five to fourteen days of life, and pneumonia at one to three months. The pneumonia is classically afebrile, with tachypnoea, a repetitive staccato cough, diffuse crackles without wheeze, hyperinflation with bilateral interstitial infiltrates on radiograph, and peripheral eosinophilia — an unusual finding in bacterial pneumonia and a useful clue. Treatment is oral macrolide, erythromycin or azithromycin, which also eradicates nasopharyngeal carriage; topical therapy for the conjunctivitis is inadequate. Erythromycin in infants under six weeks carries a small risk of infantile hypertrophic pyloric stenosis. The staccato cough should be distinguished from the paroxysmal cough of pertussis, which comes in prolonged fits followed by an inspiratory whoop and post-tussive vomiting, and from croup's barking cough. Erythromycin ointment given at birth prevents gonococcal but not chlamydial ophthalmia.