At a Glance:
- Psoriasis is a skin condition that leads to red and scaly lesions that can be found anywhere on the skin
- Around 1.6 million Australians are living with psoriasis
- Psoriasis is usually a chronic condition, but those who are affected may have periods of remission
- Psoriatic arthritis affects one in five people with psoriasis
- Psoriatic arthritis is typified by painful, swollen and stiff joints, and sometimes leads to permanent joint deformities
- There is no cure for psoriasis or psoriatic arthritis but there are a number of effective treatments
What is Psoriasis?
Psoriasis is an autoimmune condition that affects the way skin cells develop. In a typical person, new cells develop deep in the skin and slowly rise to the surface. Once the skin cells rise to the surface they die and fall off, to be replenished by a new layer of cells. The typical life cycle of a skin cell is around a month.
In psoriasis there is excess production of new skin cells leading to thick red, scaly plaques, which are at times painful and/or itchy. Psoriasis may affect any part of the body but is most typically found over the knees, on the back of the elbows, and scalp.
Although the condition is chronic, people with psoriasis may experience periods of remission with few or any symptoms between flare-ups.
What is Psoriatic Arthritis?
Around one to two out of every 10 people with psoriasis may also experience a condition called psoriatic arthritis.
Whilst most people who develop psoriatic arthritis will also have skin psoriasis sometimes the arthritis may appear before the skin lesions, or without any skin psoriasis.
Psoriatic arthritis may affect any joint in the body, including the spine. The joints that are impacted do not correlate to where the skin lesions are.
Presentation of Psoriasis
Although all forms of psoriasis are caused by the rapid growth of skin cells, the condition may present in a number of different ways, including:
- Plaque Psoriasis - the most common form of psoriasis, plaque psoriasis causes the skin to form raised red plaques covered in whitish or silver scales. These lesions are typically itchy, and the dry skin may crack and bleed. Plaque psoriasis is most commonly found on the elbows, knees, and scalp but may appear anywhere, including the palms and soles.
- Nail Psoriasis - psoriasis may affect both finger and toenails. Nail changes include pits in the nail, the nail to life from the nail bed (onycholysis) and for them to become abnormal in appearance (onychodystrophy)
- Guttate Psoriasis - guttate psoriasis is usually triggered by throat infection by the bacteria Streptococcus. It usually occurs a few days to weeks following an infection, and there are small plaques often on the limbs and trunk. It usually resolves on its own but sometimes needs treatment.
- Inverse Psoriasis - inverse psoriasis is found in skin folds such as those in the groin, under the arms, buttocks or under the breasts. The condition is typified by patches of smooth red skin that become worse with friction or sweat.
- Hand and Foot Pustular Psoriasis - this type of psoriasis is found on the palms of the hands or soles of the feet. If the lesions present in larger, widespread patches on the body the condition may be referred to as Generalised Pustular Psoriasis.
- Erythrodermic Psoriasis - the rarest form of the condition, erythrodermic psoriasis is when more than 90% of the body is covered with psoriasis. This can be serious and require admission to hospital.
In addition to skin lesions, psoriasis may lead to a number of different complications or increase the risk of developing other conditions, including:
- Cardiovascular disease
- High blood pressure
- Mental health conditions, such as low self-esteem and depression (due to appearance and discomfort)
- Obesity
- Type 2 diabetes
Symptoms of Psoriatic Arthritis
In addition to the potential presence of psoriasis , other symptoms of psoriatic arthritis include:
- Stiffness and low back pain, most often experienced in the morning
- Swollen joints,
- Pain or tenderness in joints
- A reduction in range of joint motion
- Pain in tendons and ligaments
- Swollen, sausage-like fingers and toes (referred to as dactylitis)
- Tiredness
What Causes Psoriasis and Psoriatic Arthritis?
The exact cause of psoriasis and psoriatic arthritis are unknown. Psoriasis is thought to be an immune system problem that causes the skin to regenerate at faster than normal rates. In the most common type of psoriasis, known as plaque psoriasis, this rapid turnover of cells results in scales and red patches. Just what causes the immune system to malfunction isn't entirely clear.
Anyone may develop psoriasis but there appear to be a number of risk factors that increase a person’s chance of developing the condition, including:
- Genetic Predisposition - having a family history of psoriasis may increase your chance of developing psoriasis. Having one parent with psoriasis increases the chance of developing the disease, but if both parents have psoriasis, the chance of a child developing the condition is greatly increased.
- Stress - as stress may affect the immune system, long term stress, or intense stress may increase your risk of developing psoriasis, or make existing psoriasis worse.
- Smoking - not only may smoking increase your chances of developing psoriasis, it appears as though smoking may also increase the severity of the disease.
- Obesity - being obese appears to increase a person’s chance of developing psoriasis and may also increase the severity of psoriasis.
People with a predisposition to developing psoriasis may not show any signs of the condition until it is triggered. Anything may trigger an outbreak or flare-up of psoriasis, but there appear to be a number of common triggers, including:
- Bacterial infections, such as Streptococcal throat or skin infections
- Skin injuries
- Stress may be both an underlying cause to develop psoriasis and be a trigger for a flare-up
- Weather or changes in environment. Cold and dry climates are an especially common trigger
- Smoking
- Heavy alcohol consumption
- Obesity
- Medications, including lithium, high blood pressure medications such a beta-blockers, antimalarial drugs or withdrawal from oral corticosteroid medications
Similar underlying causes and triggers may also be responsible for the development of psoriatic arthritis. While any form of psoriasis may trigger the development of psoriatic arthritis, there appears to be a greater risk of developing the condition if you have nail psoriasis.
If you have a red, scaly rash that just won’t go away, or have swollen joints (or both) you may need to make an appointment to see a doctor .
Living With and Treatment for Psoriasis and Psoriatic Arthritis
Psoriasis and psoriatic arthritis are incurable but there are a number of possible treatment options available to help people manage outbreaks or discomfort. Treatments are broken into three main groups - topical, phototherapeutic and oral or injected treatments.
The choice of treatments differs from case to case and is based on the severity of the psoriasis, location, and how you respond to different treatments. Finding a suitable treatment may take time to trial different methods. In Australia, to be eligible for subsidised treatments, such as biologics, you must have previously undergone and failed a number of other treatment options.
Topical Treatments
A topical treatment is something that is applied directly to the affected area, such as lotions, ointments and creams. Commonly used topical treatments for psoriasis include:
- Corticosteroids - the most common form of treatment for mild to moderate cases of psoriasis, corticosteroids are typically used to treat flare-ups as well as manage remissions. Long term use of corticosteroids may lead to reduced effectiveness in combating symptoms as well as thinned skin.
- Vitamin D - synthetic vitamin D may be used to help slow skin growth and may be prescribed to be used in conjunction with corticosteroids, or as a replacement for use in sensitive areas.
- Coal Tar - tar therapy is an old but still commonly used treatment for psoriasis as tar based creams or lotions may effectively reduce the scaling, itch and inflammation associated with a psoriasis lesion. Coal tar products are quite cheap and readily available, but tar has a pungent smell and can stain anything it comes in contact with.
- Moisturisers - hydrating dry scaly skin may help keep it from cracking, peeling or tearing.
Phototherapy
Exposure to natural or artificial light is one of the front line treatments used for treatment of psoriasis. Typically phototherapy is an ongoing treatment, with patients needing frequent light exposure to gain the benefits of the treatment.
- UVB Exposure - both broadband and narrowband UVB light may be used as a treatment for psoriasis. This form of phototherapy requires the use of specialised UVB light machines and regular treatments. Typically a person undergoing UVB phototherapy will be treated two or more times a week (for around 30 minutes at a time) until remission, at which time the frequency of treatment may drop.
- Excimer Laser - a strong UVB light (laser) is used to more directly target and aggressively treat affected areas. Excimer laser therapy only targets the affected skin and due to the power of the light typically requires fewer treatment sessions to be effective.
- PUVA - psoralen plus ultraviolet A (PUVA) treatment involves the use of psoralen, a topical treatment that increases sensitivity to UVA in conjunction with UVA light. The psoralen allows the UVA to penetrate deeper into the skin for aggressive treatment of severe psoriasis. The treatment may be effective but it also has a number of potential side effects including dry, wrinkled or freckled skin, nausea, headache and an increased risk of melanoma.
- Heliotherapy - brief, clinically advised daily exposure of the affected areas to sunlight.
Oral or Injected Treatments
Oral or injected treatments are often only prescribed after topical or phototherapeutic treatments have failed. Most oral or injected treatments require the patient to have regular blood tests as a number of them may affect liver function and blood count.
- Retinoids - derivatives of vitamin A, retinoids (such as Acitretin) are pills used to reduce the production of skin cells.
- Immunosuppressant Medications - Methotrexate is a commonly used immunotherapy for the control of psoriasis. The pill is typically taken once per week and suppresses the immune system in an effort to slow the production of new skin cells and reduce inflammation.
More powerful immunosuppressants, such as cyclosporine, may be used to combat severe cases of psoriasis. Unlike methotrexate, cyclosporine may not be used as an ongoing treatment and should not be used for more than a year. Before starting immunosuppressant therapy, people are required to be up to date with immunisations.
- Biologics - these drugs are usually administered via injection and are typically reserved for people who have not responded to front line treatments like topical therapies, phototherapy and methotrexate. Biologics, such as ustekinumab (Stelara) may improve symptoms in weeks but repeat injections are required to maintain effectiveness. This is typically done on an eight or 12 week schedule.
Both immunosuppressant therapies and biologics may be effective in treating psoriatic arthritis as well as lesions. Other treatments for psoriatic arthritis depend on the severity and location of the inflammation. Treatment options include steroid injections, NSAIDS (non-steroidal anti-inflammatory drugs) and pain relievers.