Another potential adverse reaction to an antibiotic is wheezing. More rare is an acute life-threatening allergic reaction, such as tissue swelling in the throat that restricts the ability to breathe or a sudden, dangerous drop in blood pressure. Diarrhea and other common adverse reactions to an oral antibiotic are rarely, if ever, the result of an allergic reaction to the drug. One way is to consider the child's and the family's medical history. A child who has previously reacted to penicillin is ten times more likely to react to any antibiotic drug.
Hereditary influence can play a role in drug reactions.
Studies indicate that if one parent has reacted to a drug, the children are fifteen times more likely to have a reaction by the age of sixteen. Other factors include the type of medication that is used and how often administered. For example, a child who suffers from numerous infections will usually be treated with antibiotics, despite the fact that most of the infections are caused by viruses. This is because it is often difficult for the primary care physician to distinguish a bacterial from a viral infection. A small number of children may develop a reaction to an antibiotic after they have received repeated doses of the medication.