Corticosteroids (CSs) play a major role in the dermatological treatment due to their potent anti-inflammatory and immunosuppressive properties. They are used as first line in most autoimmune bullous dermatoses, autoimmune connective tissue diseases, neutrophilic dermatoses and vasculitis. Systemic CSs are usually administered orally, but intravenous and intramuscular preparations are also available. CSs differ in their relative anti-inflammatory and mineralocorticoid effects and duration of ACTH suppression. CSs with minimal mineralocorticoid effects and an intermediate half-life are usually selected to decrease sodium retention and reduce adverse effects. Adverse effects are mainly due to the alteration of electrolyte and water balance, the inhibition of tissue repair process, the activation of gluconeogenesis, the increase of infection risk, the inhibition of the secretion of ACTH and the risk of growth retardation in children. Prednisolone is commonly the oral medication of choice because it has a sufficiently prolonged action to ensure the sustained effectiveness of a single daily dose, has minimal mineralocorticoid activity and is biologically active, differently from other CSs that need to be transformed into their active forms in the liver. The daily dose of prednisone varies depending on the severity of the dermatological condition and ranges from 0.5 to 2 mg/kg/day. A single daily dose is preferable, given in the morning when there is maximal adrenocortical cortisol secretion. Treatments that last longer than 4 weeks should not be stopped abruptly to avoid acute adrenal insufficiency and a flare of the dermatological condition. In conclusion CSs provide an effective response for several dermatological conditions and dermatologists should be aware of their therapeutic properties and their side effects to prevent serious complications.