Antibiotic Treatment for Skin and Soft Tissue Infections

Introduction to Antibiotic Options

The Infectious Diseases Society of America (IDSA) recommends dicloxacillin 250-500 mg four times a day orally for the treatment of impetigo and skin infections caused by Staphylococcus aureus and Streptococcus, with a strength of evidence based on clinical trials 1
Both dicloxacillin and cefalexin demonstrate good activity against methicillin-susceptible Staphylococcus aureus (MSSA) and Streptococcus species, making them appropriate options for skin and soft tissue infections caused by these pathogens, as supported by studies 2, 3, 1

Dicloxacillin is active against Staphylococcus aureus, including penicillinase-producing strains, but not MRSA, as reported in clinical studies 1
The IDSA guidelines recommend cefalexin 250-500 mg four times a day (or 25-50 mg/kg/day in 3-4 divided doses in children) for the treatment of impetigo, with a moderate strength of evidence 1

Neither dicloxacillin nor cefalexin is active against MRSA, highlighting the need for alternative treatments in cases of suspected MRSA infection, as emphasized by the IDSA 2, 3, 1
For purulent infections with suspected MRSA, consider clindamycin, doxycycline, or trimethoprim-sulfamethoxazole as alternative treatments, based on clinical guidelines 1
The IDSA guidelines note that first-generation cephalosporins, including cefalexin, have higher rates of therapeutic failure when used for DAIR strategies compared to other agents, with a low strength of evidence 4
For severe or complicated infections, consider initial parenteral therapy, as recommended by the IDSA 1

The American College of Physicians recommends dicloxacilina for skin and soft tissue infections caused by Staphylococcus aureus sensitive to methicillin (MSSA) and beta-hemolytic streptococci, with a dosage of 250 mg four times a day orally in adults and 12 mg/kg/day divided into 4 doses in children 5
The Infectious Diseases Society of America suggests dicloxacilina 500 mg four times a day orally as a first-line agent for empirical coverage of beta-hemolytic streptococci in non-purulent cellulitis 6, 7
Dicloxacilina 500 mg four times a day orally is recommended for mild diabetic foot infections, according to the International Working Group on the Diabetic Foot 8, 9

The World Health Organization recognizes that dicloxacilina and flucloxacilina have better oral bioavailability than cloxacilina within the class of anti-staphylococcal penicillins 8, 9
For purulent cellulitis, dicloxacilina is not appropriate as initial monotherapy because these infections are frequently caused by community-acquired MRSA, and alternative agents such as clindamycin or trimethoprim-sulfamethoxazole should be considered 6, 7

Dicloxacilina 500 mg four times a day orally may be used as chronic suppression therapy after initial intravenous treatment for MSSA osteomyelitis, as recommended by the Orthopaedic Infectious Diseases Society 10
For prosthetic joint infections, dicloxacilina 500 mg three or four times a day orally is recommended for indefinite chronic antimicrobial suppression in infections caused by oxacillin-sensitive staphylococci 10