Psoriasis

Diagnosis 

Psoriasis is usually diagnosed based on the appearance of the skin lesions (a clinical diagnosis). Sometimes, a skin biopsy may be required to rule out other causes of a rash.1  

Treatment  

Psoriasis is a chronic (long-lasting, persistent) disorder which may improve or worsen over time. There is no cure at this time. However, treatments may be used very effectively to decrease signs and symptoms.1 

There are several types of treatment available for people with psoriasis which include: 

Topical medications8 

• Topical corticosteroids (creams, ointments or lotions) are recommended for plaque psoriasis. They are recommended as first line for mild psoriasis.9  
• Milder steroid creams may be used in the skin folds (where skin rubs together).  
• Other topical agents include vitamin D analogs, retinoids, and calcineurin inhibitors that can be used alone or in combination with steroids.8 
• Other topical treatments like moisturizers with or without salicylic acid can be used alone or in combination with steroids. 

Ultraviolet (UV) Radiation: Phototherapy 

• In summer months or on sunny winter vacations, individuals often notice improvement of psoriasis with sun exposure.  
• Different types of UV radiation treatment, most commonly narrow band UVB,10 may be available at your dermatologist’s office or at a specialized phototherapy centre. In some places, home phototherapy is available. 
• It is important to note that therapeutic phototherapy is different from tanning beds, which are not recommended. Tanning beds emit mostly UVA radiation which is not effective for psoriasis. The use of tanning beds is associated with an increased risk of skin cancer - therapeutic narrowband UVB is not. 

Systemic medications (oral medications)13 

• Methotrexate may be used to treat moderate to severe psoriasis in adults, including plaque psoriasis, erythroderma, generalized pustular psoriasis, and palmoplantar psoriasis. 
• Methotrexate may also be given as an intravenous, intramuscular, or subcutaneous injection.  
• Acitretin is an oral retinoid that may be used for moderate to severe psoriasis in adults. 
• Apremilast may be used to treat moderate to severe psoriasis in adults. 
• Cyclosporine may be used to treat severe psoriasis, and can also be used for erythrodermic, generalized pustular psoriasis, and palmoplantar psoriasis. Cyclosporine is not recommended for longterm use. 

Biologics      14 

Biologics, which target the individual components of the immune system, work to block the molecules that contribute to inflammation: interleukin 23 (IL-23), interleukin 12/23 (IL-12/23), interleukin 17 (IL-17), and TNF (tumour necrosis factor). They are generally reserved for people who have not responded to other treatments, due to their high cost. However, biologics may have fewer side effects than cyclosporine, methotrexate, and acitretin. They can be very effective as a treatment for moderate to severe psoriasis.  

Biologics include:  

• TNF-alpha inhibitors (etanercept, infliximab, adalimumab, certolizumab) 
• IL-12/IL-23 inhibitors (ustekinumab) 
• IL-17 inhibitors (secukinumab, ixekizumab, brodalumab) 
• IL-23 inhibitors (guselkumab, risankizumab) 

For the treatment of women of child-bearing potential, TNF-alpha inhibitors and IL-12/IL-23 inhibitors have not shown negative maternal-fetal outcomes.15 Data for IL-17 and IL-23 inhibitors is currently limited. All biologics are likely safe during breastfeeding. 

Alternative medicines8 

Due to lack of evidence or conflicting evidence there are no current recommendations for alternative therapies, including:  

• Diet/dietary supplements  
• Mind/body interventions (stress reduction, meditation, hypnosis) 
• Herbal therapies (Aloe Vera and St. John’s Wort) 
• Traditional Chinese Medicine 

Treatments available for children with psoriasis include16:  

• Calcipotriol ointment with or without topical steroids.     17 
• If psoriasis is resistant treatment with creams and ointments narrow band UVB phototherapy may be helpful if it is accessible. Methotrexate may be used when topical treatment and phototherapy have not been successful.  
• Etanercept, adalimumab, and ustekinumab are biologics approved in Canada for the treatment of psoriasis in children.18 

*All information on medical treatments on this site is provided as an overview only. For a complete list of benefits, side effects, warnings and precautions, read the product’s package insert and consult your doctor or a pharmacist. 

**If you are considering an alternative or complementary therapy, discuss it with your doctor first, and always be sure to keep your doctor up to date about any vitamins, supplements, or other forms of alternative treatment you are taking. Like any medication, alternative therapies can interact with other medications/treatments and may have side effects of their own. Remember that “natural” does not necessarily mean “safe.” 

The CPSA gratefully acknowledges Nadia Kashetsky, MSc, MD candidate, Memorial University of Newfoundland, and Cheryl F. Rosen, MD, FRCPC, for assistance in the preparation of this report. October 2021.  

Psoriasis is a common chronic inflammatory skin disorder causing areas of the skin to become thickened and often covered with silvery scales.1 In individuals with darker skin tones, areas with psoriasis may look purple, dark brown, dark gray, or red as compared to red in individuals with lighter skin tones.2–4  

Psoriasis occurs mainly in adults, however children and adolescents can develop psoriasis too.1 Females and males are equally affected, and psoriasis is not contagious or an infection.1 Psoriasis affects between 0.2% to 4.8% of the population.5 There are several types of psoriasis as described below.3 

Plaque psoriasis  

• The most common type of psoriasis, 80-90% of cases.1 
• Skin plaques are usually 1-10cm in diameter but may be larger.  
• It can occur at any age but tends to begin in young to middle aged adults. 
• The severity varies between individuals and over time from mild, moderate, to severe. 
• It may occur in a few small areas or may cover a large part of the body. 
• The most commonly affected locations include the back of the elbow, the front of the knee (extensor surfaces), and the lower back.  
• Psoriasis may or may not be itchy. 
• Plaques of psoriasis may occur on the scalp.  Psoriasis does not cause hair loss. 

Further anatomical classification of plaque psoriasis6 

Inverse psoriasis  

• Named “inverse” because the presentation is on the flexor surfaces or skin folds.1  
• Can occur in the armpits, groin, genitals, buttocks and under the breasts.  

Nail psoriasis  

• May cause tiny pits in the nails, brown or salmon-coloured spots, or cause the nails to separate from the nailbed.  
• If severe, nails may thicken and crumble.  
• Seen in 60-80% of patients with psoriasis.  

Palmoplantar psoriasis 3 

• Occurs on the palms of the hands and soles of the feet.  
• Like other types of psoriasis, the skin can crack, bleed and be painful.  
• There is also a variant of palmoplantar psoriasis that results in pus-filled bumps, called palmoplantar pustulosis. 

Guttate psoriasis 

• A sudden eruption of small scaly papules primarily on the trunk. 
• Tends to affect children or young adults.  
• May occur after a recent streptococcal infection.  

Other Types of Psoriasis  

Pustular psoriasis  

• May be generalised (spread out over the body) or localised (on smaller, specific areas of the body).  
• The generalized type is rare and may be severe with a rapid onset of multiple small pustules (pus-filled bumps) which may join to form larger pustules.  
• With generalized pustular psoriasis, people may have fever, chills, malaise, and enlarged lymph nodes. 
• Palmoplantar pustulosis is a localised form of pustular psoriasis located on the palms of the hands and soles of the feet.  

Erythrodermic psoriasis7 

• Rare 
• The entire skin surface becomes red (erythematous) and scaly.  
• People may have fever, chills, malaise, enlarged lymph nodes, joint pain, and a faster heart rate. 

Comorbidities (conditions associated with psoriasis) 

Psoriatic arthritis1 

• An inflammatory arthritis (joint pain and swelling).  
• About 1 in 3 people who have psoriasis will develop psoriatic arthritis. 
• Psoriasis develops first in 85% of people, however 15% of people experience arthritis first. 
• About 80-90% of people with psoriatic arthritis may have nail involvement

Depression 

The prevalence of depression is higher in people with psoriasis.  

Obesity, heart disease, diabetes, and metabolic syndrome  

There is an increased incidence of these conditions in people with psoriasis.  

What is the cause of psoriasis? 

The exact cause of psoriasis has not yet been identified. However, psoriasis is thought to develop from a combination of genetic, immune, and environmental factors.1  

Genetic Factors  

Although there is no genetic test to tell you whether you will develop psoriasis, about 40% of individuals with psoriasis or psoriatic arthritis have family members with the disorder.   

Immune Factors 

In psoriasis, immune cells produce molecules (Interleukin 23, interleukin 12/23, TNF) that contribute to inflammation. These molecules enter the skin through blood vessels, and cause the outer layer of skin (the epidermis) to become thicker, growing very fast without time to develop correctly, leading to surface scaling. Blood vessels in the middle layer of skin (the dermis), dilate which causes redness. 

Environmental Factors 

Environmental factors that have been linked to psoriasis include: 

• Bacterial and viral infections 

• Alcohol  
• Certain medications (beta blockers, lithium, antimalarial drugs)  
• Smoking  
• Trauma 

Signs and symptoms of psoriasis may include1: 

• Raised areas of skin (plaques) that appear red, purple, brown, or gray depending on the person’s skin colour 
• Silvery scales 
• Itchiness and/or pain of affected areas may be present 
• Pitting, discolouration, or crumbly nails  

If you are living with psoriasis or know someone who is, you may want to stay up to date on the condition as well as current treatments and news.   

Our Partner Organization 

Canadian Association of Psoriasis Patients: www.canadianpsoriasis.ca  

Our Affiliate Members 

Canadian Psoriasis Network www.canadianpsoriasisnetwork.com 

Resources

The Painting Psoriasis Project Volume 8 Issue 3 (click image to view)	Psoriasis: Mild, moderate, severe Volume 4 Issue 1 (click image to view)