What antibiotic would you prescribe for a patient with chronic axillary and groin pustules?

Treatment of Chronic Axillary and Groin Pustules

For a patient presenting with chronic pustules in the axillae and groin, start with oral tetracyclines (doxycycline or lymecycline) for at least 12 weeks, as this presentation is consistent with hidradenitis suppurativa (HS), and tetracyclines are the first-line systemic antibiotic therapy. 1

Initial Antibiotic Management

First-Line Therapy

• Prescribe oral doxycycline 100 mg daily or lymecycline 300-600 mg daily for a minimum of 12 weeks 1
• The British Association of Dermatologists gives this recommendation a strong rating (↑↑), making it the evidence-based starting point for HS management 1
• Consider treatment breaks after the initial course to assess ongoing need and minimize antimicrobial resistance risk 1
• Always combine systemic antibiotics with topical benzoyl peroxide to prevent resistance development 1

Second-Line Therapy for Non-Responders

• If the patient fails to respond to tetracyclines after 12 weeks, escalate to combination therapy with oral clindamycin 300 mg twice daily PLUS rifampicin 300 mg twice daily for 10-12 weeks 1
• This combination also carries a strong recommendation (↑↑) from the British Association of Dermatologists for tetracycline-refractory cases 1

Clinical Reasoning

Why This is Hidradenitis Suppurativa

• The anatomic distribution (axillae and groin) with chronic pustular lesions is pathognomonic for HS 2, 3
• HS characteristically affects apocrine gland-bearing areas with recurrent painful nodules, abscesses, and pustules 2
• The "upper type" HS involves axillary regions while the "lower type" involves inguinal and genital areas; this patient has both 3

Why Tetracyclines First

• Tetracyclines have both antimicrobial activity against secondary bacterial infection AND intrinsic anti-inflammatory properties that address the underlying pathophysiology 4, 5
• Doxycycline specifically inhibits molecular inflammatory pathways beyond its antibiotic effects, making it ideal for chronic inflammatory conditions like HS 5
• The evidence base for tetracyclines in inflammatory skin conditions is robust, with demonstrated superiority over placebo 4

Important Caveats and Pitfalls

What NOT to Do

• Do not prescribe topical antibiotics as monotherapy - this is ineffective for HS and promotes resistance 1
• Do not use isotretinoin - the British Association of Dermatologists specifically recommends against this (↓↓) unless there are concomitant moderate-to-severe acneiform lesions elsewhere 1
• Do not confuse this with simple bacterial folliculitis - chronic recurrent pustules in these specific locations require HS-directed therapy, not short-course antibiotics for acute infection 2

Monitoring Considerations

• Screen for HS-associated comorbidities including depression, anxiety, diabetes, hypertension, and hyperlipidemia 1
• Refer to smoking cessation services if applicable, as smoking is a triggering factor 1, 2
• Refer to weight management services if relevant, as obesity aggravates the condition 1, 2
• Monitor for gastrointestinal symptoms that might indicate inflammatory bowel disease, which is associated with HS 1

Doxycycline-Specific Warnings

• Be aware of dose-dependent phototoxic reactions with doxycycline 4
• Rare cases of symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) can occur with doxycycline, presenting as symmetric pruritic erythematous papules in flexural areas 6
• If SDRIFE develops, discontinue doxycycline and switch to an alternative tetracycline or the clindamycin-rifampicin combination 6

Beyond Antibiotics

When to Escalate

• If both tetracyclines and clindamycin-rifampicin combinations fail, consider non-antibiotic systemic therapies including acitretin, dapsone, or adalimumab 40 mg weekly for moderate-to-severe disease 1
• Topical clindamycin 1% solution can be added as adjunctive therapy 1
• Intralesional corticosteroid injections may be used for individual acute lesions 1

Adjunctive Measures

• Provide appropriate dressings for draining lesions 1
• Address pain management as needed 1
• Educate the patient about the chronic nature of HS and realistic treatment expectations 1