Psoriasis which is resistant to topical treatment and phototherapy is treated by medications that are taken internally by pill or injection.

  1. As a first step, medicated ointments or creams are applied to the skin. This is called topical treatment.
  2. If topical treatment fails to achieve the desired goal then the next step would be to expose the skin to ultraviolet (UV) radiation. This type of treatment is called phototherapy.
  3. The third step involves the use of medications which are ingested orally or by injection. This approach is called systemic treatment.
  4. Over time, psoriasis can become resistant to a specific therapy. Treatments may be periodically changed to prevent resistance developing (tachyphylaxis) and to reduce the chance of adverse reactions occurring. This is called treatment rotation.