Steroid Atrophy - Cause

Cause

Steroids downregulate IL-1 (Interleukin-1), an inflammatory cytokine that causes cornification in skin cells (which induces dermatitis), while the action of fibroblasts, which produce new skin cells, are suppressed. This starts atrophy of the skin.

Within two weeks of starting Topical Steroid treatment, and probably within a few days, microscopic degenerative changes may be seen in the epidermis with a reduction of cell size and the number of cell layers. These effects may be rapidly reversible but with chronic administration dermal changes become apparent. There is inhibition of the mitotic activity of fibroblasts resulting in reduction of collagen and glycosaminoglycan synthesis but probably the earliest evidence of dermal atrophy is a reduction in the diameter of the fibrils and then the collagen bundles become atrophic and separated. The latter effects have been reported to be caused by the inhibition of collagenase by steroids. Elastin fibres in the upper layers of the dermis become thin and fragmented whereas those deeper down compact into a dense network. As a result of atrophic changes such as striae, telangiectasias, purpura and ecchymosis develop. Long-term use of steroids causes irreversible atrophy, while atrophy induced by short-term use may to some extent be reversible except for striae.

Corticosteroids are absorbed at different rates depending on the thickness of the stratum corneum. A mild topical steroid that works on the face may achieve little on the palm. But a potent steroid may quickly cause side effects on the face.

For example:

• Forearm absorbs 1%
• Armpit absorbs 4%
• Face absorbs 7%
• Eyelids and genitals absorb 30%
• Palm absorbs 0.1%
• Sole absorbs 0.05%,

Absorption is greater in an ointment base, in the presence of a keratolytic agent such as salicylic acid and under occlusion. Strong topical steroid (e.g., fluorinated steroids) can induce the condition very quickly, while a weaker steroid can induce it slowly over time. Corticosteroid preparations that contain urea or salicylic acid are more potent than those containing the corticosteroid alone, as these ingredients increase the absorption of the steroid into the skin.