Is cephalexin (a cephalosporin antibiotic) a suitable treatment option for an adult patient with an auricle infection, assuming no known allergy to cephalosporins and normal renal function?

Cephalexin for Auricle Infection

Cephalexin is NOT the optimal antibiotic choice for auricular perichondritis or auricle infections, as these infections are most commonly caused by Pseudomonas aeruginosa, against which cephalexin has poor activity; fluoroquinolones (ciprofloxacin or levofloxacin) are the recommended first-line treatment. 1

Understanding Auricular Infections

Auricular perichondritis is a serious infection that:

• Typically occurs within the first month after ear piercing, especially during warm weather 1
• Presents as painful swelling, warmth, and redness of the auricle that characteristically spares the earlobe 1
• Can be distinguished from superficial skin infection by acute tenderness when deflecting the auricular cartilage 1
• May progress from minor infection to perichondritis, abscess formation, and cartilage necrosis with or without systemic symptoms 1

Pathogen Coverage and Treatment Selection

The most common pathogens causing auricular infections are:

• Pseudomonas aeruginosa (most common) 1
• Staphylococcus aureus 1
• Streptococcus pyogenes 1

Cephalexin has inadequate coverage for Pseudomonas aeruginosa, which is the predominant pathogen in these infections. 1, 2 While cephalexin demonstrates excellent activity against staphylococci and streptococci 2, 3, its antimicrobial spectrum does not include the most critical pathogen for auricle infections.

Recommended Antibiotic Treatment

Fluoroquinolones are the treatment of choice because they provide coverage for all three common pathogens:

• Ciprofloxacin or levofloxacin respond well to the typical bacterial causes 1
• These agents specifically target Pseudomonas aeruginosa while maintaining activity against staphylococci and streptococci 1

Alternative Options for Hospitalized Patients

If hospitalization is required or the infection is severe, alternative parenteral options include:

• Clindamycin 1
• Ceftazidime 1
• Cefepime 1

The choice among these alternatives depends on the specific pathogen identified and local resistance patterns. 1

Surgical Intervention

If an abscess develops, surgical incision and drainage are often necessary. 1 Once abscess formation occurs, achieving good cosmetic preservation of the auricular cartilage becomes difficult. 1

Important Clinical Pitfalls

• Do not use cephalexin for suspected auricular perichondritis due to inadequate Pseudomonas coverage 1, 2
• Distinguish between superficial skin infections (where cephalexin might be appropriate) and deeper perichondrial infections by assessing for tenderness with cartilage deflection 1
• Early recognition and appropriate antibiotic selection are critical to prevent progression to abscess formation and cartilage necrosis 1
• The characteristic sparing of the earlobe helps differentiate perichondritis from simple cellulitis 1