The detection of IgE antibodies to penicillin by a skin test is affected by the amount of time between the original allergic drug reaction and the skin test. Many patients with documented IgE antibodies to penicillin by skin test lose the sensitivity with time. It is estimated that up to 80% of patients with a history of immediate reactions to penicillin will have a negative skin test at 10 years. 18 However, these patients may be at increased risk of sensitization to penicillin on subsequent administration compared with the rest of the population. 17
In Type III immune complex reactions to a drug, elevation of nonspecific inflammatory markers such as erythrocyte sedimentation rate and C-reactive protein may occur. If available, more specific laboratory testing for complement levels (CH50, C3, C4) or circulating immune complexes can be conducted. Positive tests help confirm the clinical diagnosis; negative tests do not exclude the diagnosis of immune complex disease. Systemic vasculitides induced by medication may be detected by autoantibody tests such as antinuclear antibody or antihistone antibody. 28
Severe vaccine reactions Severe vaccine reaction This is not a regulatory term. It refers to vaccine reactions that usually do not result in long-term problems, but can be disabling and, rarely, life threatening. Severe reactions include serious reactions but also include other severe reactions. include, among others, seizures Seizure Uncontrolled electrical activity in the brain, resulting in convulsion, physical signs, thought disturbances, or a combination of symptoms. , thrombocytopenia Thrombocytopenia A severe decrease in the number of blood platelets, the cells involved in clotting. Thrombocytopenia may stem from failure of platelet production, splenic sequestration of platelets, increased platelet destruction, increased platelet utilization, or dilution of platelets. , hypotonic hyporesponsive episodes (HHE) Hypotonic hyporesponsive episode (HHE) A recognized serious reaction to immunization, especially pertussis-containing vaccine. It is defined as an acute loss in sensory awareness or loss of consciousness accompanied by pallor and muscle hypotonicity. No long-term sequelae have been identified in the small number of children who have had long term follow-up. HHE is not a contraindication for further doses of pertussis vaccine. and prolonged crying, which all need to be reported. Most severe vaccine reactions do not lead to long-term problems. Anaphylaxis, while potentially fatal, is treatable without leaving any long-term effects.