Benzoyl peroxide is an acne medication that comes in many forms, including a soap that's impregnated with the medication. Benzoyl peroxide treats your acne in three ways: by killing bacteria, peeling away dead skin cells and drying excess skin oil. It is sold over the counter and by prescription.
While benzoyl peroxide is readily available in soap form, it isn't safe for everyone. If you have an allergic skin disorder like eczema or seborrheic dermatitis, you should talk with your doctor before using soap with benzoyl peroxide. Benzoyl peroxide also interacts with other drugs, tobacco, alcohol and some foods, so it's important to discuss its use with a healthcare professional before buying the medicated soap. Benzoyl peroxide soaps also can be irritating if they're used on sunburned or wind-burned skin.
It's important to remember that soap with benzoyl peroxide is considered a medication to be used according to label directions. According to Drugs.com, you should wash acne lesions with the benzoyl peroxide soap for one to two minutes, rinse thoroughly with water and pat dry with a towel. If you miss a dose of benzoyl peroxide, use the medicated soap as soon as you can. However, if it's almost time for your next dose, skip the one you missed and resume your normal schedule.
Benzoyl peroxide can cause significant skin irritation if it's not applied correctly, explains Medline Plus. When using soap containing the drug, keep it away from your lips or eyes, sensitive skin on your neck and the inside of your nose. Don't apply products that contain alcohol or other ingredients that dry out the skin. Because benzoyl peroxide makes your skin more sensitive to light, limit your exposure to sunlight, tanning booths and sunlamps. Drugs.com states that benzoyl peroxide can interact with sunscreens that contain para-aminobenzoic acid, or PABA, to cause temporary discoloration of the skin.
Benzoyl peroxide can cause temporary side effects including mild redness, peeling, stinging or warmth of the skin area where it's applied. In some cases, it may cause more severe burning, blistering, crusting, swelling or marked redness of the skin. You should let your doctor know if the temporary effects don't go away or if you have any of the more severe side effects.
Soap with benzoyl peroxide may irritate your skin for several weeks, making your acne worse before it gets better. However, according to Drugs.com, you should see a significant improvement in your acne symptoms within two to three weeks.