Complex sentence: For secondary erythromelalgia, treatment of the underlying primary disorder is the most primary method of treatment, though aspirin has been thought to reduce symptoms of erythromelalgia it is rare to find evidence that this is effective.
Split into simpler sentences: For secondary erythromelalgia, treatment of the underlying primary disorder is the most primary method of treatment. Although aspirin has been thought to reduce symptoms of erythromelalgia, it is rare to find evidence that this is effective.