Allergic sensitivity to a topical corticosteroid is usually only picked up when an eczematous dermatitis being treated by a topical corticosteroid fails to respond to treatment or worsens. In cases of persistent or exacerbating dermatitis treated with corticosteroid preparations, corticosteroid sensitivity should be considered. However, it may also be due to irritation from or allergy to other components of the preparation such as preservatives . Lanolin , ethylenediamine , quaternium-15 and the antibacterial agent neomycin , are all known to be potent sensitisers.
Corticosteroids have powerful anti-inflammatory effects because they indirectly inactivate a wide range of transcription factors. Both cytokine production and the expression of adhesion molecules required for the entry of inflammatory cells into target tissues are thus inhibited. Low-dose corticosteroids are often used in a cream form to treat atopic dermatitis, as nose drops to treat rhinitis, or as an inhaled agent to treat asthma. Corticosteroids have very few side effects when used at a low dose to treat atopic conditions, but high-dose, long-term or oral use of corticosteroids can have severe consequences, including general immunosuppression.