Skincare While on Antibiotics: What to Know

Antibiotics affect the skin through several mechanisms — some directly therapeutic, some as side effects that require routine adjustment. Oral antibiotics (doxycycline, minocycline, erythromycin) are commonly prescribed for moderate-to-severe acne. They work by reducing C. acnes colonisation and suppressing inflammatory mediators. Side effects relevant to skincare include: Photosensitivity: This is the most important and most frequently under-communicated side effect. Tetracyclines (doxycycline, minocycline) significantly increase UV sensitivity — photosensitivity reactions can occur with very limited sun exposure that would normally cause no reaction. SPF 50+ every day is not optional while on these antibiotics. Microbiome disruption: Oral antibiotics reduce not just pathogenic bacteria but also the commensal bacteria that normally compete with Malassezia yeast. This is why fungal acne (Malassezia folliculitis) frequently appears during or after antibiotic courses. If you develop new small, uniform papules on the forehead or chest during antibiotic use, suspect fungal acne. Dryness and sensitivity: Some antibiotics, particularly doxycycline, cause increased skin dryness and sensitivity in some users. This is not universal, but it's worth being aware of.

Based on the mechanisms above, here's how to adjust your routine: Non-negotiable changes: • SPF 50 broad-spectrum every single morning, regardless of weather. If on tetracyclines, consider reapplying midday for the duration of the course. • Reduce or eliminate sun exposure during peak UV hours (11am–4pm) where possible. Precautionary changes: • If you use any exfoliating acids, consider reducing frequency — the combination of antibiotic-induced sensitivity and AHA/BHA exfoliation can increase irritation. • Have an antifungal shampoo available (ketoconazole 2%) in case Malassezia folliculitis develops. A 2-week course as soon as you notice suspicious uniform papules will resolve it faster than waiting for confirmation. What doesn't need to change: • Your general routine — cleanser, moisturiser, core serums • Topical acne treatments, unless skin becomes reactive • Tretinoin, unless irritation increases significantly

Topical antibiotics for acne work differently from oral antibiotics and have less systemic impact, but there are still routine considerations. Clindamycin (1%) and erythromycin (2–4%) are the most commonly prescribed topical antibiotics for acne. They're usually combined with benzoyl peroxide in modern prescribing to reduce antibiotic resistance development. Routine integration: • Topical antibiotics are usually applied once or twice daily to acne-affected areas after cleansing • Do not layer directly on top of BPO — apply to different areas or at different times • Standard moisturiser and SPF are still required and compatible Resistance consideration: Dermatological guidelines recommend using topical antibiotics for no longer than 3 months. Always combined with BPO or another non-antibiotic anti-acne treatment. Long-term monotherapy with topical antibiotics creates resistant C. acnes populations that then fail to respond to future antibiotic treatments. After completing an antibiotic course: Transitioning to a maintenance regime with BPO, BHA, and/or retinoid keeps acne managed without antibiotic dependence. Most dermatologists outline a transition plan — if yours didn't, ask specifically.