Oral challenge with penicillin without prior skin- or blood test – a safe method?

Background

The diagnosis of penicillin allergy is hard to establish and probably overused, partly because of fear of severe reactions. These are however very rare. The investigation of children with suspected allergy to antibiotics often includes skin tests and/or blood tests for sensitisation, prior to oral challenge (OC). These tests have shown to be of limited significance when it comes to beta-lactam antibiotics.

Methods

We perform oral provocations on children with a suspected allergy to beta-lactam antibiotics, without prior skin- or blood testing for sensitisation. During the years 1998-2008 OC where performed with phenoxymethylpenicillin (PcV) in 490 children, 0-18 years old (384 (78%) < 6 years old). 85% had reacted on treatment with PcV, the rest had reacted on treatment with amoxicillin or cephalosporin. One week after the oral challenge we contacted the families to find out late reactions.

Results

22 children (4,5%) had some form of reaction during the OC. Most reactions were mild skin reactions, some with moderate itch. Some children had nausea or vomited. After the OC, when at home, 9 children reacted with a mild rash or mild gastrointestinal symptoms. Those children were not considered as allergic to penicillin.

Three children received the diagnosis of penicillin allergy.

Child A
had reacted with angioedema on the first dose of PcV within 10 minutes. The oedema faded spontaneously, without any medication. At the oral challenge the child reacted within a few minutes with urticaria, and a severe itch. No dyspnoea or disturbance of circulation. The reaction faded within a few minutes after administration of drugs.

Child B
had rea
cted with urticaria taking PcV. OC was performed twice. Both times the child reacted with moderate urticaria some hour after the challenge.

Child C
had an
immediate reaction on the first dose of PcV, with itch, urticaria, hoarseness and angioedema. At OC he developed itch in soles of hand and feet, and a mild rash. The reaction faded even before anti-histamine was given.

 

Conclusion

Allergy to penicillin is rare among children, and the diagnosis is probably overused. In our material none of the children had a severe reaction at the OC.  This indicates that OC without prior skin-or blood test is a safe method. The diagnosis of penicillin allergy is hard to establish and should not be established without prior investigation.