The term "irritability" is used specifically in regard to infants and young children who, when ill, demonstrate increased fussiness, whining, and fretfulness despite attempts at comforting and soothing.
Irritability is seen at the beginning of many infectious diseases, some metabolic diseases, head trauma, malignancies, and other types of disease. It can be a very early sign of serious problems. Although irritability is not a symptom of any specific illness, it should arouse suspicion in the parent that something might be wrong with the child, even though there may not yet be other symptoms. Parents are usually very aware of their child's normal behavior and may pick up early changes that would be unremarkable to the examining health care provider. This may aid in the early diagnosis of illness.
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