Severe pulmonary exacerbation in cystic fibrosis caused by cat allergy

This paper describes a preschool child who had persistent symptoms suggestive of significant cystic fibrosis lung disease over a period of eighteen months following first isolation of Pseudomonas aeruginosa. Despite vigorous anti-infective treatment and extensive investigations seeking undetected infection, improvement only occurred once severe cat allergy was diagnosed and cats were removed from the household. Whilst infection is the most common cause of respiratory exacerbations in cystic fibrosis, this article serves as a reminder that it is important to consider non-infective pathologies when the response to anti-infective treatment is unexpectedly poor.