Ascia‐p28: Fewer Than 50% of Patients Commencing Scit Complete a 3 Year Course

Abstract

Background: Drug induced anaphylaxis is an uncommon yet potentially life-threatening immediate drug hypersensitivity reaction. Here we report a case of anaphylaxis caused by two structurally unrelated antibiotics, cefazolin and ciprofloxacin, with evidence of allergies to both compounds on subsequent testing.Case report: A 26-year-old man sustained a finger injury and was treated with intravenous cefazolin immediately followed by intravenous ciprofloxacin. Within a few minutes of commencing the ciprofloxacin infusion, he developed sneezing, chest tightness, dyspnoea, wheezing, cough and facial rash. The infusion was ceased and he was effectively treated with adrenaline and intravenous hydrocortisone. He had no previous history of drug allergy. He was assessed 6 months later and his intradermal wheal and flare response to cefazolin (2mg/ml) was 11x11mm. Intradermal tests to PPL, MDM, benzyl penicillin, amoxicillin and ceftriaxone were negative. A supervised challenge to oral ciprofloxacin, a known irritant, was subsequently performed as cefazolin was suspected to be the likely culprit in this case. After the final total dose of 500mg, he developed anaphylaxis with generalised rash and severe hypotension requiring multiple doses of intramuscular adrenaline and administration of intravenous fluid. He recovered without any sequelae.Conclusion: Ciprofloxacin and cefazolin allergy are both rare and there is no evidence of cross-reactivity of IgE to these compounds. Therefore, the chance of an individual developing an anaphylaxis caused by concurrent administration of two drugs where patients are allergic to both compounds is extremely low. However, this case highlights the fact that this exceptional event can still occur and highlights the importance of supervised challenge to assess for a drug allergy even when one drug allergen has been identified. Background: Subcutaneous immunotherapy (SCIT) to aeroallergens is offered to patients with symptoms and signs consistent with allergic disease and sensitisation proven by skin prick testing or specific IgE. Duration of treatment is a minimum of 3 years, but information is lacking regarding the completion rate at our centre. ASCIA-P28 FEWER THAN 50% OF PATIENTS COMMENCING SCIT COMPLETEMethod: Medical and pharmacy records were audited for patients who began SCIT to aeroallergens at Sir Charles Gairdner Hospital in 2011 (expected SCIT completion by 2015). Patients who discontinued treatment were contacted via telephone to clarify the reasons.Results: A total of 53 patients were identified -the mean age was 40.6 years and 62% of patients were female. 87% commenced SCIT due to allergic rhinitis. Allergen choice was predominantly grass pollens (85%) and house dust mite (51%). Only 23 patients (43.4%) successfully completed a 3 year course, with the biggest loss of patients occurring within the first year (n = 17, 32.1%). Reasons for discontinuation in the first year included lack of efficacy (n = 6, 11.3%) and adverse reactions: systemic (n = 3, 5.7%), immediate (n = 1, 1.9%). ...