Treatment of a Boil on the Foreskin in a Sexually Active Adult Male
A boil (furuncle) on the foreskin should be treated with oral anti-staphylococcal antibiotics, specifically dicloxacillin 250-500 mg every 6 hours for 7-10 days, along with warm compresses and incision and drainage if fluctuance develops. 1
Initial Assessment
The key diagnostic priority is distinguishing a simple boil (furuncle) from other penile conditions that require different management:
Rule out cellulitis: Look for diffuse erythema, warmth, and edema extending beyond a localized abscess. Cellulitis presents with rapidly progressive swelling of the penile shaft and requires urgent treatment. 2, 3, 4
Rule out sexually transmitted infections: In sexually active men, obtain urethral swab for Gram stain (looking for >5 polymorphonuclear leukocytes per oil immersion field) and nucleic acid amplification testing for N. gonorrhoeae and C. trachomatis. 5
Rule out epididymitis: Check for testicular pain, tenderness, and hydrocele, which would require different antibiotic coverage (ceftriaxone plus doxycycline). 5, 6
Assess for trauma: Ask about recent sexual activity or injury that could serve as a portal of entry for bacteria. 2, 4
Antibiotic Selection
For uncomplicated furuncles (boils), oral anti-staphylococcal penicillins are first-line:
Dicloxacillin 250 mg every 6 hours for mild-to-moderate infections, or 500 mg every 6 hours for severe infections 1
Take on an empty stomach (1 hour before or 2 hours after meals) with at least 4 ounces of water, and NOT in the supine position or immediately before bed to prevent esophageal complications 1
Continue therapy for at least 48 hours after the patient becomes afebrile and asymptomatic 1
Alternative regimens if penicillin-allergic:
- Consider cephalexin or clindamycin (though not specifically mentioned in the provided evidence, these are standard alternatives based on general medical knowledge)
Adjunctive Measures
Warm compresses applied to the area 3-4 times daily to promote spontaneous drainage
Incision and drainage if the boil becomes fluctuant (indicates abscess formation)
Avoid sexual activity until the infection has completely resolved to prevent transmission and further trauma 5
Critical Pitfalls to Avoid
Do not mistake this for lichen sclerosus, which presents as porcelain-white plaques on the glans, coronal sulcus, or foreskin and requires topical corticosteroids, not antibiotics. 5
Do not delay treatment if cellulitis is present: Penile cellulitis can progress rapidly and cause skin gangrene if not immediately treated with IV antibiotics and surgical decompression. Group B hemolytic streptococci are the usual causative organisms in cellulitis. 7, 4
Monitor for treatment failure: If no improvement occurs within 3 days, consider alternative diagnoses including abscess requiring drainage, resistant organisms, or underlying conditions like diabetes. 1
Follow-Up
Reassess in 48-72 hours to ensure clinical improvement
If the lesion persists despite adequate antibiotic therapy, consider biopsy to rule out other conditions including neoplastic change, particularly if there is hyperkeratosis, erosion, or unusual appearance 5
Obtain bacterial culture if drainage occurs to guide antibiotic selection 1