Intralesional fluorouracil (50 mg per mL, two to three times per week) appears to shrink keloids safely while avoiding the tissue atrophy and telangiectasia that may occur with repeated corticosteroid injections. 30 Combining fluorouracil with corticosteroid injections and pulsed dye laser produced superior results more rapidly than corticosteroid injections alone or corticosteroids with fluorouracil. 13 Good to excellent responses at 12 weeks as rated by a blinded observer were 15 percent for triamcinolone acetonide, 40 percent for triamcinolone plus fluorouracil, and 70 percent for all three modalities (all significant). Combining corticosteroids and fluorouracil diminished the adverse effects of corticosteroids. Rare skin complications of fluorouracil may include hyperpigmentation and wound ulceration. No systemic adverse effects (., anemia, leucopenia, thrombocytopenia) occurred in this study.
It is widely suspected that the anaerobic bacterial species Propionibacterium acnes ( P. acnes ) contributes to the development of acne, but its exact role is not well understood.  There are specific sub-strains of P. acnes associated with normal skin, and moderate or severe inflammatory acne.  It is unclear whether these undesirable strains evolve on-site or are acquired, or possibly both depending on the person. These strains have the capability of changing, perpetuating, or adapting to the abnormal cycle of inflammation, oil production, and inadequate sloughing of dead skin cells from acne pores. Infection with the parasitic mite Demodex is associated with the development of acne.   It is unclear whether eradication of the mite improves acne.