Corticosteroids: use in dermatology

Corticosteroids: use in dermatology

Introduction

Corticosteroids have anti-inflammatory and immunosuppressant effects that are useful in a number of skin disorders. Modification of the naturally occurring hydrocortisone molecule has produced a large number of drugs with varying anti-inflammatory potency, for topical or systemic use.

Topical corticosteroids

The potency of topically applied corticosteroids is assayed by the degree of vasoconstriction they produce when applied under an occlusive dressing. This depends on the concentration used, the intrinsic activity of the compound and its ability to penetrate the barrier of the epidermis, which may be influenced by the vehicle in which it is applied. The assay permits topical corticosteroid preparations to be arranged in groups with similar potency. Such a ranking corresponds approximately with clinical effectiveness 

Adverse effects of topical corticosteroids may be due to local effects on the skin or mucosa at the site of application or to systemic effects following absorption of the drug Potential local effects include:

• loss of dermal collagen, leading to skin atrophy, formation of striae, fragility and easy bruising

• telangiectasia (development of prominent blood vessels)

• promotion of infection

• idiosyncratic reactions (eg allergic contact dermatitis, perioral dermatitis)

• purpura (in the elderly).

• The intensity of adverse effects is proportional to the therapeutic effect and thus increases with the potency of the preparation.

• Suggested potencies and preparations for long-term use of topical corticosteroids for chronic dermatoses are:

• face and flexures—hydrocortisone 1%

• trunk—betamethasone valerate 0.02%, triamcinolone acetonide 0.02%

• elbows/knees and palms/soles—betamethasone dipropionate 0.05%, mometasone furoate 0.1%, methylprednisolone aceponate 0.1%.

Penetration of corticosteroid to the dermis is greater on the face, the scrotum, and where conditions mimic application under occlusion such as flexures and intertriginous areas. The use of the more potent corticosteroids on these sites therefore carries greater risk of local damage and they should be used with caution. The only corticosteroids that are safe to use on these sites are hydrocortisone and desonide. In certain circumstances, more potent corticosteroids (eg methylprednisolone aceponate) may be used intermittently on these sensitive areas for up to two weeks; however, the greater the potency the greater the risk of local adverse effects—particularly perioral dermatitis. If improvement does not occur after two weeks, do not persevere with treatment—reconsider the diagnosis and seek expert advice.

With greater potency, there is also an increased risk of rebound on withdrawal.

Absorption of the more potent agents applied to large areas may cause suppression of the hypothalamic pituitary axis and other complications usually associated with systemic corticosteroid administration

Practical issues to consider when prescribing topical corticosteroids are discussed in the Pertinent practical points chapter.

For important issues to consider when using topical corticosteroids in children, 

Systemic corticosteroids

Oral corticosteroids are often used in serious skin diseases or when topical corticosteroids are ineffective. Prednisolone and prednisone are the most commonly used oral corticosteroids in dermatology. The major limiting factor in the use of oral corticosteroids is the development of extensive, dose-related adverse effects.