Mechanism of local skin atrophy caused by intradermally injected corticosteroids.

Different hydrocortisone microcrystal suspensions applied intradermally in rabbits caused skin atrophy. This could be ascribed to secondary tissue degeneration as was ascertained histologically. The degree of degeneration was related to the concentration of the suspension, size of the microcrystals and frequency of the intervals between the injections. The ground substance of the connective tissue changes and is characterized by a basophilic granular mass, homogenized collagen fibers and degeneration of the elastic fibers. The pathomechanism of local skin atrophy not only differs from connective tissue degeneration caused by systemic corticosteroid treatment but also from the degeneration caused by topical treatment.