Case Presentation: A 55 year old male with a known history of sarcoidosis, hypertension, and penicillin allergy (anaphylaxis) presented with complaints of right swollen testicle associated with pain and dysuria for 2 weeks. Few days prior to the admission, the patient went to an urgent care facility and was treated with Ceftriaxone and Azithromycin. The course of antibiotics resolved the pain and dysuria, but the swelling persisted, which prompted the visit to the emergency room. Upon evaluation, ultrasound of the scrotum showed a moderate-sized hydrocele on the right along with an enlarged epididymis and some mild increased flow within the testicular parenchyma consistent with epididymo-orchitis. The patient was started on IV Levofloxacin for treatment of epididymo-orchitis. Shortly after initiation of Levofloxacin, the patient complained of throat tightness and pruritus, and was found to be hypotensive with respiratory distress, and wheezing. Vitals were noted to be BP 67/38, HR 90, RR 18 and oxygen saturation 97% on high flow oxygen supplementation. Physical exam was significant for bilateral wheezing in all lung fields with poor air entry. Anaphylactic reaction to Levofloxacin was suspected and rapid response was called. Levofloxacin was stopped immediately and the patient was started on 1L of NS bolus, Solu-medrol 125 mg IV, Benadryl 50 mg IV and Pepcid 20 mg IV. Patient responded well to anaphylaxis treatment.
Discussion: An allergy to penicillin is the most common drug allergy affecting about 10 percent of all patients and 15 percent of hospitalized patients. These patients are often treated with broad- spectrum antibiotics like fluoroquinolones or vancomycin, which may be responsible for more side effects, higher costs, increase in drug resistance and may not be as effective as penicillins for some infections. Even though one prospective study showed that patients with antibiotic sensitivity had a 10-fold increased risk for allergic reactions to unrelated antibiotics, there is little to no data regarding cross-reactivity between penicillins and fluoroquinolones. Fluoroquinolones typically cause two types of hypersensitivity reactions: 1. delayed-onset maculopapular exanthema, which are generally benign; and 2. immediate reactions which can cause urticaria, pruritus, flushing, angioedema, wheezing, nausea, abdominal symptoms, and/or hypotension/shock.
Conclusions: Even though cross-reactivity between penicillin and fluoroquinolones is rare, it can cause life threatening anaphylaxis and could be fatal within minutes of administration of the offending agent. Diagnostic tests for immediate fluoroquinolone hypersensitivity are not substantiated or standardized, in contrast to tests for penicillin hypersensitivity. Therefore, a thorough history (including timeline, immediate or delayed, severity of past reaction, and treatment given at the time of the reaction), prompt recognition of allergic reaction and immediate treatment are needed. It is important for the patients with severe anaphylactic reaction to penicillin to be monitored closely when being started on treatment with fluoroquinolones to avoid fatal anaphylaxis.