This case discussion highlights the need to consider the cause of a condition when selecting treatment.
A 31-year-old man presented with patches of a persistent, red and slightly scaly rash over his neck, trunk (particularly the upper half) and proximal arms (Figure 1a). It had been a problem for four years, worsening during the summer months. On one occasion the rash flared while the patient was on holiday for a few weeks in a tropical country. He was also troubled by pale marks left by the rash, mainly on his trunk (Figure 1b).
The patient had been diagnosed with pityriasis versicolor and treated with terbinafine cream twice daily for one month with only partial success. He had then been given a two-month course of 500 mg griseofulvin daily with no effect.