Complex sentence: In severe cases of PM and DM with systemic signs, an initial three to five days on intravenous corticosteroid (methylprednisolone) may be used; otherwise, treatment begins with a single daily (after breakfast) high dose of oral corticosteroid (prednisone).
Split into simpler sentences: In severe cases with systemic signs, an initial three to five days on intravenous corticosteroid (methylprednisolone) may be used. Otherwise, treatment begins with a single daily (after breakfast) high dose of oral corticosteroid (prednisone).