Benzoyl peroxide

Benzoyl peroxide (BPO) is an acne treatment. It is available without a prescription and has been used for decades. The big advantage: there is no development of resistance.

Benzoyl peroxide has an antibacterial effect by releasing oxygen, which kills the anaerobic acne bacteria. In addition, it has a mild peeling (keratolytic) effect.

Available in various concentrations (2.5%, 5%, 10%) and formulations (gel, cream, wash lotion). Well-known brands are Benzaknen®, PanOxyl® and Aknefug BP®.

Benzoyl peroxide works by releasing oxygen:

Antibacterial mechanism:

• BPO breaks down on the skin into benzoic acid and oxygen
• The free oxygen oxidizes bacterial proteins
• P. acnes (anaerobic) is killed
• No development of resistance possible!

Keratolytic effect:

• Mild peeling effect
• Dissolves keratin plugs in the pores
• Opens clogged follicles

Why no resistance? The oxidative mechanism is nonspecific – bacteria cannot develop resistance to it. This is why BPO is indispensable for preventing resistance during antibiotic therapy.

Benzoyl peroxide is suitable for:

• Mild to moderate acne
• All forms of acne with inflammation
• As an add-on to antibiotics (prevents resistance)
• For maintenance therapy
• As an OTC treatment without a prescription

Advantages:

• No development of resistance
• Available without a prescription
• Easy to combine

Limitations:

• Can bleach fabrics
• Irritating for sensitive skin
• Dries out the skin

Concentrations:

• 2.5% – mild, for sensitive skin
• 5% – standard
• 10% – strong, for robust skin

Important: Higher concentration = more irritation. 10% is intended for severe acne and for acne in which a lower-concentration preparation has not led to treatment success.

Dosage forms:

• Gel (standard)
• Cream (for dry skin)
• Wash lotion (less irritating)
• Spot treatment

Recommendation: Start with 2.5% and increase only if well tolerated.

Applying gel/cream: 1. Cleanse the skin and let it dry 2. Apply thinly to the affected areas 3. 1-2x daily (start with 1x daily) 4. Let it absorb

Wash lotion (least irritating): 1. Apply to damp skin 2. Leave on for 1-2 minutes 3. Rinse off thoroughly 4. 1x daily

Getting used to it:

• For sensitive skin 1x daily before going to bed
• Pause in case of severe irritation

Caution:

• Bleaches fabrics (towels, pillowcases, clothing)!
• Use white bed linen and old towels
• Wash your hands after application

Do not use in case of:

• Hypersensitivity to benzoyl peroxide
• On injured or severely irritated skin
• In the area of the eyes and mucous membranes

Caution in case of:

• Very sensitive skin
• Atopic dermatitis
• Rosacea (can make it worse)
• Simultaneous use of other irritating products

Pregnancy and breastfeeding: Can be used. Low systemic absorption.

Common:

• Dry skin
• Redness
• Scaling
• Burning during application
• Itching

Uncommon:

• Allergic contact dermatitis
• Increased sensitivity to sunlight

Frequency not known:

• Allergic reactions, including at the application site, up to anaphylaxis
• Swelling of the face

Initial worsening: In the first few days, the acne may briefly appear worse.

Bleaching of fabrics: Not a side effect, but important: BPO bleaches fabrics irreversibly!

Caution when used at the same time as:

• Retinoids (tretinoin, adapalene) – increased irritation
• Other drying products
• AHA/BHA peels

Useful combination:

• With adapalene (Epiduo = fixed combination)
• With topical antibiotics (Duac = fixed combination)
• With retinoids at different times (BPO in the morning, retinoid in the evening)

Stability problem: Tretinoin is inactivated by BPO – do not apply at the same time. Adapalene is more stable.