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In a word, yes.
The standard treatment of asthma, which often includes inhaled corticosteroids, is usually effective. However, some people respond poorly and they may need frequent intermittent courses or, occasionally, long-term oral corticosteroid treatment.
Churg-Strauss syndrome is a form of vasculitis (blood vessel inflammation) that is characterized by late-onset asthma, upper airways disease including allergic rhinitis, sinusitis, and systemic vasculitis. The asthma that is part of Churg-Strauss syndrome makes it quite possible to confuse true asthma and the Churg-Strauss syndrome, and they have indeed sometimes been confused.
Anyone with asthma, especially with late-onset asthma that is hard to control and has features of a multisystem disease, may have the Churg-Strauss syndrome. When corticosteroids are taken by mouth, they can partially treat the Churg-Strauss syndrome and mask it, cover it up.
The fact that steroids may mask cases of the Churg-Strauss syndrome was addressed in an editorial by DP D'Cruz, NC Barnes, and CM Lockwood in the British Medical Journal on February 20, 1999 (BMJ 1999;318:475-476).