- Psoriasis is a serious chronic inflammatory disorder of the immune system
- It affects more than 90m people worldwide: 1.2m in Britain, 7.5m in the US
- The condition runs in families
- Symptoms include red patches of skin covered with silvery scales that itch and burn
- 30 to 40% of people with psoriasis may experience psoriatic arthritis, which may lead to chronic pain, disability and sometimes; mutilating joint disease
- New drugs are changing the prospects for people with psoriasis and psoriatic arthritis
- Dr. Sonya Abraham, Imperial College London, and British Psoriatic Arthritis Consortium describes some of the causes of psoriasis, and prospects for future therapies
At war with my skin and joints
The novelists John Updike and Vladimir Nabokov, among others, suffered from psoriasis, which significantly influenced and shaped their respective lives.
Psoriasis affects more than 100m people worldwide: 1.2m in Britain, and 7.5m in the US. 30 to 40% of these can experience psoriatic arthritis. In 2014, the WHO recognized psoriasis as a serious chronic non-communicable disease, and suggested that people with the condition suffer needlessly because of, “incorrect or delayed diagnosis, inadequate treatment options and insufficient access to care, and because of social stigmatization”.
Therapies for psoriasis include a range of topical and systemic medications as well as phototherapy. Many of the systemic therapies can also reduce the pain and disability from arthritis and other manifestations of the condition.
Health professionals have been somewhat constrained by the limited therapies specifically for psoriasis, but this is beginning to change. New treatments are improving the prospects for people with psoriasis, and psoriatic arthritis. “The outlook is good for the millions of people with the conditions”, says Dr. Sonya Abraham of Imperial College London, and a member of the British Psoriatic Arthritis Consortium (Brit-PACT):
Psoriasis is a serious chronic inflammatory disorder triggered by an immune systems fault that causes the over production of skin cells. It runs in families, and has an unpredictable course of symptoms. It mainly presents in adults, usually before the age of 35.
Psoriasis mostly affects the skin and joints, and usually occurs on the scalp, knees, elbows, hands and feet. It also may affect the fingernails, the toenails, the soft tissues of the genitals and the inside of the mouth. The condition is characterized as ‘mild’, ‘moderate’, and ‘severe’ according to the amount of body surface area (BSA) affected and the severity of redness, thickness, and scaling of the skin. Approximately 80% of those affected have mild to moderate disease, while 20% have moderate to severe psoriasis affecting more than 5% of the body surface area. The most common form of psoriasis affecting about 80 to 90% of psoriasis patients, is ‘plaque psoriasis’, which is characterized by patches of raised, reddish skin covered with silvery-white scale. There are other forms of psoriasis, including inverse, erythrodermic, pustular, guttate and nail disease.
Psoriatic arthritis and associated conditions
Below Sonya Abraham describes some of the causes of psoriatic arthritis and the effects that the condition may have on various organs of the body. Up to 40% of people with psoriasis experience joint inflammation that produces symptoms of arthritis. Psoriatic arthritis can lead to chronic pain and change in physical appearance. Patients suffering from psoriatic arthritis have reduced physical fitness, compared to psoriasis patients without arthritis. Typically, psoriatic arthritis occurs in conjunction with longstanding skin lesions, but it can occur in the absence of psoriasis.
Psoriasis and psoriatic arthritis may be associated with other diseases and conditions. The incidence of Crohn’s disease and ulcerative colitis, two types of inflammatory bowel disease, is 3.8 to 7.5 times greater in psoriasis patients than in the general population. Patients with psoriasis also have an increased incidence of lymphoma, heart disease, obesity, type-2 diabetes and metabolic syndrome. Depression and suicide, smoking, and alcohol consumption are also more common in psoriasis patients.
Causes of psoriatic arthritis
What does psoriatic arthritis do to the body?
Living with psoriasis
Updike was affected by psoriasis throughout his whole life, and his writings provide a vivid insight into the significant physical and psychological challenges that sufferers face. In his book Self Consciousness he devotes a chapter to the condition, and in 1985 he wrote a personal history of his psoriasis for The New Yorker entitled, “At War with My Skin”.
Updike says that he became a writer because of his psoriasis: “writers do not have to be presentable”. He married young because he found a person “who forgave” his skin, and moved to a small town in Massachusetts near a beach where he could swim and sunbath to relieve his symptoms. During the cold New England winters Updike moved to the Caribbean where he could continue to swim and sunbathe. The stress of leaving his wife in 1974 aggravated his condition, which resulted in a failure of his salt water and sun therapy. Consequentially, he enrolled in what was then an experimental light therapy, which, together with some systemic medication cleared his skin.
Nabokov was deeply disturbed by his psoriasis, which he tried to conceal, except to people close to him. In 1937, after suffering a bad attack, he wrote to his wife describing his agony, "I continue with the radiation treatments every day, and am pretty much cured. You know, now I can tell you frankly, the indescribable torments I endured before these treatments, drove me to the border of suicide; a border I was not authorised to cross because I had you in my luggage”.
Treatment options for psoriasis
Updike and Nabokov’s descriptions provide insights of the devastating impact that psoriasis can have on the quality of life. Until recently, there has been few drugs specifically targeted for psoriasis, but this is beginning to change and the outlook for people with psoriasis and psoriatic arthritis looks promising. Here we describe some of the new medications that have recently come to market. But before doing so, we briefly describe current therapies.
Mild to moderate psoriasis
Mild to moderate psoriasis is managed with topical therapies, which are not very effective. These include coal tar, emollients, salicylic acid, topical retinoids and corticosteroids, and forms of vitamin D, which can sometimes be used together with other medications.
People with moderate to severe psoriasis may be treated with traditional systemic medications, phototherapy or biologic agents. In cases of more extensive psoriasis, topical agents may be used in combination with phototherapy, or traditional systemic or biologic medications. Phototherapy includes narrowband and broadband ultraviolet B (UVB), and furocoumarins plus UVA (PUVA), which have to be used sparingly because light therapies may increase the risk of skin cancer.
Psoriatic arthritis therapies
In the video below, Sonya Abraham describes some of the conventional therapies for psoriatic arthritis. Medical treatment regimens for the condition include the use of non-steroidal anti-inflammatory drugs (NSAIDs), and disease-modifying anti-rheumatic drugs (DMARDs). Conventional therapy usually consists of NSAIDs and local corticosteroid injections, with DMARDs being reserved for NSAID-resistant cases. However, because 40% of patients may develop erosive and deforming arthritis the early use of more aggressive treatment with DMARDs may be warranted.
DMARDs include methotrexate, sulfasalazine, cyclosporine, and leflunomide, as well as biologic agents, such as monoclonal antibodies targeting tumour necrosis factor therapies (TNF) - alpha, interleukin-12/23 (IL-12), IL-17, or IL-23.
In September 2013, the US Food and Drug Administration (FDA) approved ustekinumab, an IL-12/23 inhibitor, for the treatment of active psoriatic arthritis in adults who have not responded adequately to previous treatment with non-biologic DMARDs. The drug was already approved in Europe and the US for treatment of moderate to severe psoriasis plaques in adults.
A monoclonal antibody is an antibody produced by a single clone of cells, and is therefore a single pure type of antibody. Monoclonal antibodies can be made in large quantities in a laboratory, and are a cornerstone of immunology, and increasingly are being introduced as therapeutic agents. The anti-Tumour necrosis Factor Therapies, (anti-TNF) monoclonal antibody biologics include adalimumab, certolizumab, golimumab, infliximab, and the fusion protein, etanercept. All have FDA and EU approvals. Immunology is a branch of biomedical science that covers the study of all aspects of the immune system in all organisms.
Secukinumab is an immunosuppressant that reduces the effects of a chemical substance in the body that can cause inflammation. It works by blocking a certain natural protein in your body (interleukin-17A) that may cause inflammation and swelling. Marketed by Novartis as Cosentyx®, it is the first drug to target psoriatic arthritis, and could help those who suffer from the worst effects of the condition. The therapy is self-administered by a monthly injection, and is aimed at the parts of the immune system known to make proteins called interleukins, which are believed to be faulty in the amounts of serum they release. Up to 84% of psoriatic arthritis patients treated with Cosentyx® at two years had no radiographic progression in their joints. Clinical studies found 80% of patients saw a 75% improvement after using the drug for 12 weeks. 70% saw a 90% improvement by week 16. 405 found their symptoms disappeared completely.
Mark Tomlinson, from Novartis, the drug manufacturer, said: “In those without psoriasis, the immune system is like an orchestra; each section perfectly balanced and working harmoniously together. When a person has psoriasis, it is like one violinist in the orchestra playing out of tune. It dominates the sound and rhythm. IL-17A is like a maverick violinist”.
Apremilast is a recently licenced oral drug for psoriasis and psoriatic arthritis, which inhibits the phosphodiesterase enzyme, which in turn has affects on regulating pro and anti-inflammatory cytokines and proteins such and TNF and IL-17. In randomised control studies, Apremilast has shown improvement in psoriasis skin and arthritis disease activity assessments.
Another new anti-IL-17 drug, ixekizumab a cloned antibody, has been approved for treating adult patients with moderate to severe plaque psoriasis (covering 10% or more of the body) who are candidates for phototherapy or medications that are absorbed into the blood stream (systemic therapy). Ixekizumab has been shown to clear symptoms in 80% of people. Research published in the New England Journal of Medicine in 2016, suggests that Ixekizumab neutralises the inflammatory effects of an interleukin, a protein in the skin that carries signals to cells.
To test the drug's efficacy over time, three studies enrolled 3,736 adult patients at more than 100 study sites across 21 countries. Researchers assessed whether the drug reduced the severity of the symptoms of psoriasis compared to a placebo, and evaluated its safety by monitoring any side effects. By 12 weeks, 76 to 82% of people in the study had their condition classified as 'clear' or 'minimal'; compared to 3.2% of patients in the placebo. By 60 weeks, 69 to 78% showed their improved condition had been maintained. Kenneth Gordon, professor of dermatology at Northwestern University, and the first author of the study, said: 'Based on these findings, we expect that 80% of patients will have an extremely high response rate to ixekizumab, and about 40% will be completely cleared of psoriasis.”
None of these new drugs represent a magic bullet, but they do appear to provide significant relief for a substantial percentage of sufferers of psoriasis and psoriatic arthritis.