What You Have: Most Likely Scalp Folliculitis (possibly Folliculitis Decalvans)

What Is It?

Causes

1. Staphylococcus aureus (Staph A bacteria) - This is the most frequently identified organism. It colonizes the follicles and triggers repeated infection cycles.
2. Abnormal immune response - The body mounts an exaggerated inflammatory response against its own follicles.
3. Predisposing factors that make flares worse:
   • Excess scalp oiliness or sweating
   • Occlusion and poor scalp hygiene
   • Shaving or scratching the scalp
   • Hot, humid weather
   • Diabetes mellitus
   • Prolonged use of topical steroids
   • Atopic dermatitis (eczema background)

Treatment Options

First-Line (Most Effective for Chronic/Recurrent Cases)

• Clindamycin + Rifampicin (oral antibiotics, 10-week course) - This combination has shown the longest remission periods in studies. It targets Staph A bacteria synergistically.
• Doxycycline (100 mg twice daily) - Also effective, though remission is shorter than the combination above.

Second-Line

• Azithromycin - useful but shorter remission
• Trimethoprim-sulfamethoxazole (TMP-SMX) - another option if culture confirms susceptibility
• Isotretinoin (0.5-1.5 mg/kg/day for 6-12 months) - can be very effective for persistent cases; start low (10 mg/day) to avoid a flare

Add-On / Supplemental

• Topical corticosteroids or calcineurin inhibitors to reduce inflammation
• Intralesional triamcinolone (steroid injections) directly into lesions
• Mupirocin 2% nasal ointment (twice daily for 5 days) to eradicate nasal Staph A carriage, which can be a source of reinfection

Newer Options (for resistant cases)

• TNF inhibitors like adalimumab or infliximab
• JAK inhibitors, secukinumab, apremilast
• Photodynamic therapy or Nd:YAG laser

Important Warnings

• Do NOT squeeze or pop the pustule - this can push infection deeper, cause an abscess, or lead to permanent scarring and hair loss.
• Longstanding untreated folliculitis decalvans can cause permanent bald patches where the follicles scar over and hair cannot regrow.
• A dermatologist may do a swab culture to identify the specific bacteria and its antibiotic sensitivity before prescribing.
• Rule out tinea capitis (fungal scalp infection), which can look identical and requires antifungal treatment instead - this is an important step.

What You Should Do Now

1. See a dermatologist - ideally get a swab or culture of the pus, and possibly a scalp biopsy to confirm the diagnosis.
2. Ask about a clindamycin + rifampicin course if Staph A is confirmed.
3. Use a medicated antifungal/antibacterial shampoo (e.g. ketoconazole or chlorhexidine) as a gentle cleanser in the meantime.
4. Avoid anything that irritates the scalp - tight hairstyles, harsh products, or picking at the lesions.

Note: This information is for educational purposes only and does not replace a consultation with a licensed dermatologist. The recurring nature and pain you describe make in-person evaluation important.