http://www.ncbi.nlm.nih.gov/pubmed/7054773

Recurrent infection in the child.
Regelmann WE.
Abstract

In the child with recurrent infection, early recognition of defects in host defenses is critical for appropriate treatment and for patient survival and well-being. Familiarity on the physician's part with the clinical clues of an anatomic or functional defect can save time, money, and patient discomfort. When no such defect is apparent, the problem may be in the child's immunologic system and more specific testing is necessary to identify whether the defect is in cell-mediated immunity or is in the functioning of the phagocytic, complement, or humoral system. Treatments for these problems are available, but their success depends on early diagnosis before recurrent infection and malnutrition result in irreversible tissue damage.


or see for example here:
http://www.ncbi.nlm.nih.gov/pubmed/22761184
The approach to children with recurrent infections.
Aghamohammadi A, Abolhassani H, Mohammadinejad P, Rezaei N.
Source

Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran. [email protected].
Abstract

Recurrent and chronic infections in children are one of the most common reasons for physicians' visits

--------------------------------------------------
Note added at 7 hrs (2012-10-30 15:41:31 GMT)
--------------------------------------------------

this term seems to be in use quite a lot:
"children with recurrent respiratory infections",
so if the rest of your text deals mostly with respiratory infections i think it might be safe to use this term. If in doubt I would go for the more general "children with recurrent and chronic infections"