What antibiotic can be used for a 4-year-old child allergic to Keflex (Cephalexin) and PCN (Penicillin)?

From the Guidelines

For a 4-year-old child allergic to both Keflex (cephalexin) and penicillin, azithromycin is a good alternative antibiotic choice, as recommended by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America 1. The typical dosage for azithromycin in children is 10 mg/kg on the first day (maximum 500 mg), followed by 5 mg/kg (maximum 250 mg) once daily for 4 more days. Some key points to consider when selecting an antibiotic for a child with these allergies include:

• Avoiding all beta-lactam antibiotics, including all penicillins and cephalosporins, due to potential cross-reactivity.
• Considering the type of infection being treated, as certain antibiotics work better for different infections.
• For skin infections, clindamycin might be preferred, while for respiratory infections, azithromycin is often effective.
• Ensuring the child takes the full course of antibiotics even if symptoms improve before completion.
• Monitoring for potential side effects, such as a rash, difficulty breathing, or severe diarrhea, and seeking immediate medical attention if they occur. It's also important to note that clindamycin is another option, dosed at 10-13 mg/kg every 6-8 hours (maximum 450 mg per dose) 1. However, the most recent and highest quality studies support the use of azithromycin as a first-line alternative antibiotic for children with allergies to penicillin and cephalosporins 1.

From the FDA Drug Label

Clindamycin is also indicated in the treatment of serious infections due to susceptible strains of streptococci, pneumococci, and staphylocci Its use should be reserved for penicillin-allergic patients or other patients for whom, in the judgment of the physician, a penicillin is inappropriate.

For a 4-year-old child allergic to Keflex (Cephalexin) and PCN (Penicillin), clindamycin can be considered as an alternative antibiotic option, as it is indicated for use in penicillin-allergic patients 2.

• The child's specific infection should be evaluated to determine if clindamycin is a suitable treatment option.
• Bacteriologic studies should be performed to confirm the causative organisms and their susceptibility to clindamycin.

From the Research

Antibiotic Options for a 4-year-old Allergic to Keflex and PCN

• Azithromycin is an effective and well-tolerated alternative to first-line agents in the treatment of respiratory tract, skin, and soft tissue infections in children 3.
• It is active against major pathogens responsible for infections in children, including Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae.
• Azithromycin has been shown to be safe in patients with allergy to penicillin and/or cephalosporin, with no reactions reported in a study of 48 patients 4.

Considerations for Penicillin Allergy

• Many patients report allergies to penicillin, but clinically significant IgE-mediated or T lymphocyte-mediated penicillin hypersensitivity is uncommon (<5%) 5.
• Cross-reactivity between penicillin and cephalosporin drugs occurs in about 2% of cases, less than the 8% reported previously 5.
• The frequency of immediate allergic reactions to cephalosporins is considerably lower compared to penicillins, and the degree of cross-reactivity between cephalosporins and penicillins depends on the generation of cephalosporins 6.

Alternative Antibiotics

• Cefazolin is a safe option for patients with a penicillin allergy, including those who experience Immunoglobulin E-mediated reactions such as anaphylaxis, except in cases of severe, life-threatening delayed hypersensitivity reactions 7.
• However, for a 4-year-old child allergic to Keflex (a type of cephalosporin) and PCN (Penicillin), azithromycin may be a more suitable option due to its safety profile and effectiveness in treating various infections 3, 4.