Cellulitis is a bacterial skin infection that affects the deeper layers of the skin and the tissue underneath. It can cause redness, swelling, warmth, pain, and tenderness in the affected area.
Antibiotics for cellulitis are prescribed to fight the bacteria causing the infection and prevent it from spreading. The choice of antibiotic depends on the severity of symptoms, the suspected bacteria, allergies, and whether there is a risk of MRSA.
Also recommended: Cellulitis: Symptoms, Diagnosis, Causes & Treatment tuasaude.com/en/cellulitisTreatment should always be guided by a doctor, especially if symptoms are severe, spreading quickly, or accompanied by fever. Some people may need oral antibiotics at home, while others may need IV antibiotics in the hospital.
List of antibiotics
Antibiotics that a doctor may prescribe for cellulitis include:
1. Cephalexin
Cephalexin is an oral cephalosporin antibiotic commonly used as a first-line treatment for uncomplicated non-purulent cellulitis. It helps treat infections caused by streptococci and methicillin-sensitive Staphylococcus aureus, also known as MSSA.
Dosing: The usual adult dose is 500 mg by mouth every 6 hours for about 5 days, although treatment may be extended if symptoms improve slowly.
Side effects: Diarrhea, nausea, vomiting, abdominal pain, rash, hives, angioedema, rare anaphylaxis, Stevens-Johnson syndrome, toxic epidermal necrolysis, and Clostridioides difficile-associated diarrhea or colitis.
Contraindications: Cephalexin should not be used by people with known hypersensitivity to cephalexin or other cephalosporins. It should be used with caution in people with serious immediate-type penicillin allergy or significant kidney impairment.
2. Dicloxacillin
Dicloxacillin is an oral penicillin-type antibiotic used for mild to moderate cellulitis caused by streptococci or MSSA. It may be especially useful when penicillinase-producing staphylococci are suspected.
Dosing: The usual adult dose is 500 mg by mouth four times daily for 5 to 7 days.
Side effects: Nausea, vomiting, diarrhea, rash, hives, angioedema, anaphylaxis, rare liver toxicity, and blood-related abnormalities.
Contraindications: Dicloxacillin should not be used by people with a history of serious hypersensitivity to penicillins, such as anaphylaxis or severe skin reactions. It should be used with caution in people with liver impairment.
3. Amoxicillin-clavulanate
Amoxicillin-clavulanate is an oral antibiotic that may be used for cellulitis when broader bacterial coverage is needed. It may be considered in cases such as animal bites, mixed infections, or facial cellulitis.
Dosing: The usual adult dose is 875/125 mg by mouth twice daily, or 500/125 mg by mouth three times daily, for about 5 to 7 days, with adjustments based on severity and kidney function.
Side effects: Diarrhea, nausea, vomiting, Clostridioides difficile infection, rash, hives, rare anaphylaxis, Stevens-Johnson syndrome, cholestatic jaundice, and liver toxicity.
Contraindications: Amoxicillin-clavulanate should not be used by people who previously had cholestatic jaundice or liver dysfunction linked to this medication. It should also be avoided in people with serious beta-lactam allergy and used with dose adjustment in significant kidney impairment.
4. Penicillin
Penicillin, such as oral penicillin V or IV penicillin G, can be used for cellulitis caused by group A streptococci. It may also be used in some cases to prevent recurrent cellulitis.
Dosing: Oral penicillin V is commonly given as 250 to 500 mg two to four times daily for mild infections, while IV penicillin G may be used for more severe streptococcal infections in hospital settings.
Side effects: Rash, hives, anaphylaxis, serum sickness-like reactions, stomach upset, diarrhea, and Clostridioides difficile infection.
Contraindications: Penicillin should not be used by people with previous immediate hypersensitivity reactions to penicillin or other beta-lactam antibiotics. Dose adjustment may be needed in significant kidney impairment, especially with parenteral forms.
5. Cefazolin
Cefazolin is an IV cephalosporin antibiotic often used in hospitalized people with moderate to severe non-purulent cellulitis. It targets streptococci and MSSA.
Dosing: The usual adult dose is 1 to 2 g IV every 8 hours, generally for about 5 days or until symptoms improve enough to switch to an oral antibiotic.
Side effects: Diarrhea, nausea, injection site reactions, rash, and Clostridioides difficile colitis.
Contraindications: Cefazolin should not be used by people with hypersensitivity to cefazolin or other cephalosporins. It should be used with caution in people with serious penicillin allergy and may require dose adjustment in kidney impairment.
6. Ceftriaxone
Ceftriaxone is an IV or IM cephalosporin antibiotic that may be used for moderate cellulitis. It is often chosen when once-daily parenteral treatment is preferred, including outpatient parenteral antibiotic therapy.
Dosing: The usual adult dose is 1 to 2 g IV or IM once daily, often for around 5 days or until clinical improvement, sometimes followed by oral antibiotics.
Side effects: Diarrhea, nausea, rash, injection site pain, biliary sludge or pseudolithiasis, and Clostridioides difficile infection.
Contraindications: Ceftriaxone should not be used by people with hypersensitivity to ceftriaxone or other cephalosporins. It should not be used with calcium-containing IV solutions in neonates and should be used with caution in severe liver and kidney impairment.
7. Clindamycin
Clindamycin is an oral or IV antibiotic that can cover streptococci and community-acquired MRSA. It may be used when MRSA coverage is needed or when a person has a beta-lactam allergy.
Dosing: The usual adult oral dose is 300 to 450 mg every 6 to 8 hours for 5 to 7 days, while IV dosing is often 600 to 900 mg every 8 hours for more severe infections.
Side effects: Diarrhea, nausea, vomiting, abdominal pain, Clostridioides difficile-associated diarrhea or colitis, rash, and rare severe hypersensitivity reactions.
Contraindications: Clindamycin should not be used by people with a history of clindamycin-associated colitis or severe hypersensitivity to the medication. It should be used with extreme caution in people with previous Clostridioides difficile infection, significant gastrointestinal disease such as colitis, or severe liver impairment.
8. Trimethoprim-sulfamethoxazole
Trimethoprim-sulfamethoxazole, also called TMP-SMX, is an oral antibiotic commonly used for purulent cellulitis or cellulitis with MRSA risk factors. It may be used alone in some MRSA-predominant infections or combined with a beta-lactam antibiotic when streptococcal coverage is also needed.
Dosing: The usual adult dose is 1 to 2 double-strength tablets, containing 160/800 mg, by mouth twice daily for about 5 to 7 days.
Side effects: Rash, hives, photosensitivity, nausea, vomiting, loss of appetite, leukopenia, thrombocytopenia, megaloblastic anemia, hyperkalemia, increased serum creatinine, Stevens-Johnson syndrome, toxic epidermal necrolysis, and DRESS.
Contraindications: TMP-SMX should not be used by people with known hypersensitivity to sulfonamides or trimethoprim. It is also contraindicated or generally avoided in pregnancy near term, infants under 6 weeks, significant liver damage, severe kidney insufficiency when kidney function cannot be monitored, and documented megaloblastic anemia due to folate deficiency.
9. Doxycycline
Doxycycline is an oral tetracycline antibiotic used for MRSA-associated skin infections. It may also be considered in some cases of cellulitis when beta-lactam antibiotics cannot be used or when local tetracycline resistance is low.
Dosing: The usual adult dose is 100 mg by mouth twice daily for about 5 to 10 days, either alone for purulent MRSA-predominant infections or combined with a beta-lactam antibiotic to ensure streptococcal coverage.
Side effects: Stomach irritation, esophagitis, nausea, vomiting, diarrhea, photosensitivity reactions, tooth discoloration, and effects on bone growth in children with prolonged use.
Contraindications: Doxycycline is generally avoided during pregnancy and in children under 8 years old due to effects on teeth and bone. It should be used with plenty of water, avoided right before lying down, used with caution in severe liver impairment, and not taken with isotretinoin due to the risk of pseudotumor cerebri.
10. Vancomycin
Vancomycin is an IV antibiotic used for severe cellulitis when MRSA is suspected or when there are systemic signs of infection. It may also be used in severe infections when beta-lactam antibiotics cannot be used.
Dosing: The usual adult dose is 15 to 20 mg/kg IV every 8 to 12 hours based on actual body weight, with dosing guided by blood levels, kidney function, and infection severity.
Side effects: Kidney toxicity, red man syndrome with flushing and low blood pressure during rapid infusion, and hearing toxicity, especially at high concentrations or with other ototoxic medicines.
Contraindications: Vancomycin should be used with caution in people with pre-existing kidney impairment, as dose adjustment and therapeutic drug monitoring are often needed. Rapid infusion should be avoided to reduce infusion-related reactions.