Psoriasis
What is psoriasis?
Psoriasis is a chronic, inflammatory disorder that mainly affects the skin, causing it to develop raised, red, scaly patches, called plaques. These plaques typically appear on the elbows, knees, scalp, chest and lower back, but can appear anywhere on the body.
Psoriasis is one of a group of conditions known as autoimmune diseases. In psoriasis, the immune system becomes overactive and speeds up the growth cycle of skin cells. This abnormal growth leads to the rapid buildup of cells on the surface of the skin, resulting in the characteristic plaques.
Who is affected?
Psoriasis is one of the most common chronic skin conditions in Canada. For every 100 Canadians, three are living with psoriasis. That totals to one million people.
Although the condition can affect people of all ages, it usually begins in those between 15 and 35 years of age. People of all genders and races may develop psoriasis.
What causes psoriasis?
While it isn’t entirely clear exactly what causes the immune system to malfunction in people with psoriasis, researchers have discovered genes that are linked to the development of the condition, and it is believed that environmental triggers also play a role.
There are several factors which could contribute to the onset and exacerbation of psoriasis, including:
- Genetics: Studies have shown a positive family history in up to 40% of people with psoriasis
- Medications: Numerous medications may trigger psoriasis, including lithium, nonsteroidal anti-inflammatory drugs, antimalarials, beta-blockers and angiotensin-converting enzyme inhibitors
- Infection: Streptococcus, bacterial and viral infections have been found to trigger or exacerbate psoriasis
- Lifestyle: Being overweight, smoking and stress are triggers which are thought to make flare-ups more frequent and severe
What are the different types of psoriasis?
The most common form of psoriasis is plaque psoriasis, affecting approximately 90% of people with the condition. It usually starts with red, scaly patches and plaques that can vary from mild to severe.
- Nail psoriasis: Can cause fingernails and toenails to become pitted, discoloured or to grow abnormally. Psoriatic nails may become loose and separate from the nail bed (onycholysis), which in severe cases may cause the nail to crumble
- Guttate psoriasis: Primarily affects young adults and children and is often following an infection or other trigger
- Inverse (flexural) psoriasis: Mainly affects the skin folds, such as under the breasts, armpits, groin or buttocks
- Pustular psoriasis: Can occur in widespread patches or in smaller areas on the hands or feet, causing pus-filled lesions
- Erythrodermic (exfoliative) psoriasis: The least common but most severe type of psoriasis, can cover the entire body with a red, peeling rash that can itch or burn intensely
What are the symptoms of psoriasis?
Psoriasis can flare up anywhere on the body and can be severe or mild. Symptoms occur most often on the lower back, knees, elbows, legs, soles of the feet, scalp, face and palms but can also affect the hands, nails, skin folds and genital area.
Symptoms can vary from person to person but often include:
- Raised, red to violet patches of skin, often covered with silvery scales
- Cracked, dry or flaking skin that may bleed
- Itching or pain, sometimes severe
- Nail abnormalities, such as thickening or discolouration
In approximately 30% of people living with psoriasis, it can also affect the joints, leading to a related condition called psoriatic arthritis.
In the past 15 years, breakthroughs in the understanding of how psoriasis develops have resulted in the advancement of targeted and effective therapies. However, unmet needs remain in the treatment of psoriasis; a population-based survey identified that approximately one in three psoriasis patients reported that their primary goals of therapy, including keeping symptoms under control, reducing itching and decreasing flaking, were not met with their current treatment.
For people with mild psoriasis, topical agents remain the mainstay of treatment. Moderate to severe plaque psoriasis should be treated systemically, and biologics are recommended as an option for first-line treatment.