Safety of Direct Drug Provocation for the Evaluation of Penicillin Allergy in Low-Risk Adults.

BACKGROUND: About 10% of patients have a penicillin allergy label, but less than 5% of them are actually allergic. Unnecessary penicillin avoidance is associated with serious medical consequences. Given the growing number of these labels, it is imperative that our diagnostic strategy for penicillin allergy be as efficient as possible. The validity of traditionally used skin tests (STs) has been questioned, whereas drug provocation testing (DPT), the criterion standard, without previous ST appears very safe in most cases. OBJECTIVE: To evaluate the safety of direct DPT without consideration for ST results and the validity of ST in the diagnosis of penicillin allergy. METHODS: In this prospective cohort study without a control group, we recruited patients consulting an allergist for penicillin allergy. Patients underwent ST followed by DPT regardless of ST results. Patients with anaphylaxis to penicillin within the past 5 years or a severe delayed reaction were excluded, as were those with significant cardiorespiratory comorbidity. RESULTS: None of the 1002 recruited patients had a serious reaction to DPT. Ten (1.0%) had a mild immediate reaction, of whom only 1 (0.1%) was considered likely IgE-mediated. The positive and negative predictive values of ST for an immediate reaction were 3.6% and 99.1%, respectively. CONCLUSIONS: In a low-risk adult population reporting penicillin allergy, ST has very poor positive predictive value. Direct DPT without ST is safe and appears to be an ideal diagnostic strategy to remove penicillin allergy labels that could be implemented in first-line practice.

Recurrent acute epiglottitis in adults: defective antibody response.

BACKGROUND: Recurrent acute epiglottitis is uncommon in adults. In the medical literature, very little is known about the immune status of this population. OBJECTIVE: To evaluate the immune system of a group of four adult patients with recurrent acute epiglottitis, in what represents the largest series ever reported. METHODS: The clinical course of these episodes was carefully evaluated and a basic immune deficiency work-up was carried out for each patient. RESULTS: All four patients displayed clinical and laboratory evidence of impaired humoral immunity. One patient was splenectomized. Another patient had a below normal immunoglobulin G level. At the time of their first evaluation, none of our patients had specific antibodies against Haemophilus influenzae and one had a subnormal Streptococcus pneumoniae immunoglobulin G level for a majority of serotypes. After specific vaccination, two patients had persistent abnormalities in their response to one or more polysaccharides or conjugate-polysaccharide antigens. In the other two, the transient abnormalities were corrected by immunization. CONCLUSIONS: When recurrent acute epiglottitis occurs in adults, it is important to investigate the immune system because a quantitative or a specific antibody deficiency could be found. It also follows that these patients will be successfully treated either by immunization or antibody replacement.