Over time, affected skin can become resistant to treatment, especially when topical corticosteroids are used. Also, a treatment that works very well in one person may have little effect in another. Thus, doctors commonly use a trial-and-error approach to find a treatment that works, and they may switch treatments periodically (for example, every 12 to 24 months) if resistance or adverse reactions occur. Treatment depends on the location of lesions, their size, the amount of the skin affected, previous response to treatment, and patients perceptions about their skin condition and preferences for treatment. In addition, treatment is often tailored to the specific form of the disorder.

