Factors Associated with Self-Reported Drug Allergies in a Large Chronic Spontaneous Urticaria Cohort.

INTRODUCTION: Chronic spontaneous urticaria (CSU) is characterized by recurrent hives without a known trigger. While certain drugs are associated with urticaria exacerbations, the overall drug allergy incidence in CSU is unknown. We hypothesized that the incidence of drug allergy in CSU would be greater than the general population and that there would be distinguishing clinical features of drug-allergic CSU patients. METHODS: 362 adult CSU patients seen over a 10-year period at a University Allergy/Asthma clinic were identified. Patients reported no drug allergies or any drug allergy. Multiple drug allergies were defined as allergies to ≥ 2 chemically unrelated drugs. Using Chi-square or Wilcoxon analysis, we compared demographic features of CSU with and without drug allergy and with multiple vs. single drug allergy. RESULTS AND DISCUSSION: Overall, 202 CSU patients (56%) reported drug allergy. Drug allergic CSU patients were older, with a greater proportion of whites and higher BMI vs. CSU without drug allergy (p=0.002, p=0.047, p=0.004, respectively). Penicillin was the most common drug allergy, with urticaria the most frequently reported reaction. Female sex, white race, older age at the visit, and co-existing asthma were more common in multiple drug allergy (n=115) vs. single drug allergy (p=0.002, p=0.02, p=0.03, p=0.0002, respectively). CONCLUSION: In CSU, the prevalence of self-reported drug allergies was higher than the general population. Drug allergy is associated with older age, white race and higher BMI, while multiple drug allergy was also associated with asthma. These CSU sub-populations should be studied to avoid the potential for morbidity associated with less efficacious and more costly drugs.

Clinical implications of C6 complement component deficiency.

Background: Terminal complement component deficiencies are risk factors for neisserial infections. Objective: To review the clinical characteristics, the diagnosis and the management of patients with a terminal complement component deficiency. Methods: Pertinent articles were selected and reviewed in relation to a case presentation of C6 deficiency. Results: A case of a 56-year old patient with a history of meningitis, chronic rash, and C6 deficiency was presented, followed by discussion of clinical characteristics, diagnosis, and management of terminal complement component deficiencies. Clinical pearls and pitfalls were reviewed for the practicing allergist/immunologist and fellow-in-training. Conclusion: C6 deficiency is the most common terminal complement component deficiency and can present later in age with N. meningitidis infections. Patients can be screened for terminal complement component deficiency by checking CH50.

Drug-induced eosinophilia.

BACKGROUND: Drug reactions have been associated with increased blood eosinophil levels. OBJECTIVE: To review clinical characteristics, the diagnosis, and the management of drug-induced eosinophilia. METHODS: Pertinent articles were selected and reviewed in relation to a case presentation of drug-induced eosinophilia. RESULTS: A case of asymptomatic eosinophilia in the setting of acetylsalicylic acid (aspirin) use was presented, followed by discussion of the clinical characteristics, diagnosis, and management of drug-induced eosinophilia. Clinical pearls and pitfalls were reviewed for the practicing allergist, clinical immunologist, and fellow-in-training. CONCLUSION: Drug-induced eosinophilia is a diagnosis of exclusion. Although most cases of drug-induced eosinophilia are asymptomatic, one study showed an increased rate of hypersensitivity reactions in patients with higher eosinophil counts and earlier onset of eosinophilia.