An older adult with a history of asthma, rhinitis, and no known drug allergies has been admitted to receive IV antimicrobial therapy for bronchitis. The patient has received the oral form of the antimicrobial agent in the past. Which factors increase the risk for an allergic reaction? (Select all that apply.)

A. Subsequent use of the same antimicrobial therapy: Sensitization occurs after the first exposure; a reaction is more likely to happen upon subsequent exposures once the immune system has developed antibodies. B. IV antimicrobial therapy: The IV route introduces the allergen directly into the bloodstream, leading to a faster and potentially more severe systemic reaction than the oral route. C. Medical history of rhinitis: Patients with "atopy" (a genetic tendency toward allergic conditions like hay fever/rhinitis) have a higher statistical risk of drug allergies. D. Medical history of asthma: Like rhinitis, asthma is an atopic condition. Additionally, if an allergic reaction occurs, an asthmatic patient is at higher risk for severe bronchospasm. E. The patient's age: While older adults may have more comorbidities, age itself is not a primary risk factor for the mechanism of an allergic hypersensitivity reaction compared to the other factors.