What information should I give a patient about folliculitis and how many days should I prescribe Cephalexin (Keflex) for treatment?

Folliculitis: Patient Information and Cephalexin Treatment Duration

For uncomplicated folliculitis, prescribe cephalexin 500 mg four times daily for 7-10 days, with 5 days being sufficient if clinical improvement is evident by day 5.

What is Folliculitis?

Folliculitis is an inflammatory infection of the hair follicle, typically caused by bacteria (most commonly Staphylococcus aureus). 1 It presents as small pustules, papules, or vesicles around hair follicles, and can range from superficial inflammation to deeper involvement of surrounding tissue. 1

Patient Education Points

Key Information to Share:

• Appearance: Small red bumps or white-headed pimples around hair follicles that may be tender or itchy 1
• Cause: Usually bacterial infection, most often from staph bacteria that normally live on the skin 1
• Contagiousness: Can spread to other areas through scratching or shaving 1
• Expected course: Most cases improve within the first week of treatment, with complete clearing typically by 7-10 days 2

Self-care measures:

• Keep the affected area clean and dry
• Avoid shaving or irritating the area until healed
• Do not squeeze or pick at lesions
• Use warm compresses to promote drainage if needed

Cephalexin (Keflex) Prescription Details

Dosing:

• Adults: 500 mg orally four times daily (every 6 hours) 3, 4
• Alternative: 250 mg every 6 hours for milder cases 4
• Pediatric: 25-50 mg/kg/day divided into four doses 4

Duration:

• Standard course: 7-10 days 4
• Shortened course: 5 days is as effective as 10 days if clinical improvement has occurred by day 5 3
• For streptococcal infections specifically, continue for at least 10 days 4

Important Warnings for Patients

When to call back or return:

• Fever develops or worsens 3
• Redness spreads beyond the initial area 3
• Increased pain, swelling, or warmth 3
• No improvement after 3-5 days of antibiotics 3
• Development of severe diarrhea (may indicate C. difficile infection) 4

Medication instructions:

• Take the full course even if feeling better early—stopping early increases antibiotic resistance risk 4
• Can be taken with or without food 4
• If using liquid suspension, refrigerate after mixing and discard after 14 days 4
• Common side effects include diarrhea (most common), nausea, and stomach upset 3, 4

Clinical Decision-Making for Prescribers

When cephalexin is appropriate:

• Non-purulent folliculitis without systemic signs 3
• Mild to moderate skin and soft tissue infections 3
• No risk factors for MRSA (no IV drug use, no purulent drainage, no known MRSA colonization) 3

MRSA considerations:

• β-lactams like cephalexin are successful in 96% of typical cellulitis/folliculitis cases, even in settings with high MRSA prevalence 3
• MRSA coverage is usually unnecessary for non-purulent folliculitis 3
• Consider adding MRSA coverage (TMP-SMX, doxycycline, or clindamycin) only if: purulent drainage present, penetrating trauma, IV drug use, or treatment failure with β-lactam 3

Treatment duration rationale:

• The IDSA guidelines explicitly state that 5-day courses are as effective as 10-day courses for uncomplicated skin infections if improvement occurs by day 5 3
• This applies to cellulitis and by extension to folliculitis, which is a more superficial infection 3
• Longer courses (10 days) remain appropriate for more severe cases or when improvement is slower 4

Common pitfall to avoid:

• Do not routinely prescribe MRSA-active antibiotics for typical folliculitis—this contributes to resistance and is usually unnecessary 3
• Cultures are not needed for typical cases 3