Sulfacetamide is a sulfonamide antibiotic.
Sulfacetamide 10% topical lotion, sold under the brand name Klaron or Ovace, is approved for the treatment of acne and seborrheic dermatitis. When combined with sulfur, it is sold under the brand names Plexion, Clenia, Prascion, and Avar, which contain 10% sulfacetamide and 5% sulfur. 
Sulfacetamide has been investigated for use in the treatment of pityriasis versicolor and rosacea. It may also have anti-inflammatory properties when used to treat blepharitis or conjunctivitis. It is believed to work by limiting the presence of folic acid which bacteria need to survive. It has been suggested that sulfacetamide may also serve as a treatment for mild forms of hidradenitis suppurativa. Sulfacetamide has antibacterial activity and is used to control acne. Products containing sulfacetamide and sulfur (a keratolytic) are commonly promoted for the treatment of acne rosacea (rosacea with papules, pustules, or both). There are several prescription topical products containing sulfacetamide, such as foams, shampoos, cream and washes.
Some research indicates that sulfacetamide derivatives may act as antifungals by an CYP51A1-independent mechanism.
Adverse effects 
The most common side effects of sulfacetamide/sulfur combination products are local irritation and contact dermatitis. Sulfacetamide should not be used by individuals who have a sensitivity to sulfur or sulfa.