Long-term antibiotic usage can induce ecologic shifts in the cutaneous microflorawhich are of therapeutic importance. Suppression of a portion of the microflora is followed by the void being filled with new organisms, some of which may be pathogens. Clinical exacerbations, after initial improvement, should alert the physician to the possibility of such ecologic successions. Examples of this principle are documented in five chronic dermatoses in which antibiotics are frequently used.
Leyden JJ, Marples RR. Ecologic Principles and Antibiotic Therapy in Chronic Dermatoses. Arch Dermatol. 1973;107(2):208-211. doi:10.1001/archderm.1973.01620170020006