Hot Tub Folliculitis: Diagnosis and Treatment
Based on your recurrent itchy pustular groin rash following hot tub exposure and prior response to doxycycline, you should be treated with oral ciprofloxacin 500 mg twice daily for 7-10 days, as this represents classic Pseudomonas aeruginosa folliculitis (hot tub folliculitis).
Clinical Diagnosis
Your presentation is pathognomonic for Pseudomonas aeruginosa folliculitis:
- Hot tub exposure 1 week prior is the classic epidemiologic clue, as Pseudomonas folliculitis typically develops 8-48 hours (but can be up to 5 days) after contaminated water exposure 1, 2
- Pruritic pustular lesions in the groin/pelvic area that progressed to scabbing matches the characteristic papulopustular eruption pattern 3, 2
- Recurrence 2 months ago with doxycycline response suggests you had the same infection previously, though ciprofloxacin is the preferred agent 1
- The distribution on trunk, groin, and areas covered by swimwear is typical for hot tub folliculitis 4
Recommended Treatment
Oral ciprofloxacin 500 mg twice daily for 7-10 days is the treatment of choice:
- Ciprofloxacin provides targeted anti-pseudomonal coverage and has documented rapid efficacy in hot tub folliculitis 1
- While most cases resolve spontaneously in 7-10 days, systemic antibiotics are indicated when you have widespread lesions or recurrent disease 1, 2
- Your prior response to doxycycline (which has some anti-pseudomonal activity) supports that antibiotics will be effective 5
Alternative option: Doxycycline 100 mg twice daily for 7-10 days can be used if ciprofloxacin is contraindicated, given your prior response 5
Important Clinical Considerations
Why this is Pseudomonas and not simple cellulitis or acne:
- The hot tub exposure is the critical distinguishing feature—Pseudomonas aeruginosa thrives in warm, inadequately chlorinated water 3, 2
- True acne doesn't spread rapidly over days and isn't associated with water exposure 6
- The pustular follicular pattern with pruritus (rather than painful erythema) distinguishes this from typical cellulitis 5
Common pitfalls to avoid:
- Don't use topical acne medications—these can irritate and worsen folliculitis due to their drying effects 6
- Avoid greasy creams or occlusive ointments that can facilitate folliculitis progression 6
- Don't manipulate or pick at the lesions, as this increases infection risk 6
Supportive Care Measures
While on antibiotics, implement these adjunctive measures:
- Keep the area clean and dry—avoid hot showers and excessive moisture 6
- Apply non-occlusive moisturizers if skin becomes dry from treatment, but avoid greasy formulations 6
- Avoid the hot tub until the infection clears and ensure proper chlorination before future use 2
When to Escalate Care
Seek immediate evaluation if you develop:
- Systemic symptoms including fever, chills, or malaise—some patients with hot tub folliculitis develop low-grade fever requiring closer monitoring 3, 7
- Worsening despite 72 hours of appropriate antibiotics—this may indicate resistant organisms or an alternative diagnosis 5
- Signs of deeper infection such as increasing pain, warmth, or spreading erythema beyond the follicular pattern 5
Prevention of Recurrence
Given your second episode in 2 months:
- Investigate your hot tub's maintenance—inadequate chlorination (should be 2-4 ppm) and pH control are the primary risk factors 2, 4
- Consider having the water tested for Pseudomonas contamination if you own the hot tub 4
- Shower immediately after hot tub use and avoid prolonged immersion in potentially contaminated water 4