Biologics are drugs that are made from ‘living’ human or animal proteins, a bit like insulin for diabetics. They are designed to target a specific process or reaction in the body that is currently causing problems.
Biologics treat psoriasis and psoriatic arthritis by ‘blocking’ the overactive cells in the immune system. Most biologics are only licensed for adults, and therefore you usually have to be over-18 before your Dermatologist will prescribe them. People are prescribed biologics when topical, UV and systemics have failed to have a good enough effect on their psoriasis. Biologics that may be available to treat over 18s with severe psoriasis include adalimumab (or Humira), brodalumab (or Kyntheum), etanercept (or Enbrel), infliximab (or Remicade), ixekizumab (or Taltz) secukinumab (or Cosentyx) and ustekinumab (or Stelara).
Three of these medications, however, can be used to treat under-18s; Stelara can be prescribed to people over the age of 12, Enbrel can be prescribed to people over the age of eight, and Humira to people over the age of four. In all of these cases, this would only be when the psoriasis is severe or none of the other treatments have worked. These treatments work in slightly different ways, but all interfere with specific parts of the processes in the immune system that cause inflammation, which in turn causes psoriasis or psoriatic arthritis to occur.
Biologic treatments are taken via an injection, often in a 'pen' device. How often varies depending on which treatment you are on. As with some systemic treatments, you will have blood tests before starting treatment, and regularly whilst using your treatment, to make sure you don't have any infections or anything else that might mean the treatment isn't working as it should.
For further information on psoriasis, or for a list of resources used in the production of this information resource, please contact the Psoriasis Association. October 2018 (Review: Jun 2020).