March 13 - Psoriasis

Question 1

Describe psoriasis

Answer 1

Inflammatory and hyperplastic (increase in cell number/proliferation) disease of the skin. It is characterized by erythema (redness) and elevated scaly plaques. It is a chronic, relapsing condition. The course of the disease is often unpredictable

Question 2

What is the mean age of onset of psoriasis?

Answer 2

Mean age: approximately 23-37 years

Question 3

What is the current theory regarding the age of onset?

Answer 3

There are 2 distinct peaks with possible genetic associations:
Early onset (16-22 years; more severe and extensive and more likely to have affected first-degree family member)
Late onset (57-60 years; milder form and affected first-degree family members are nearly absent)

Question 4

Describe the etiology/risk factors of psoriasis

Answer 4

Most prevalent autoimmune condition. It very rarely affects North or South American aboriginals and Japanese. It affects men just as much as women (no hormonal impact).. Autoimmune disease (most likely): genetic predisposition +/- predisposing factor + precipitating trigger = inappropriate immune response

Question 5

What are some external predisposing factors?

Answer 5

Obesity
Alcohol consumption
Smoking
Stress
Viral/bacterial infections (e.g., HIV) - can predispose to disease onset or trigger relapse

Question 6

Describe the link between infection and psoriasis

Answer 6

Streptococcal pharyngitis (strep throat) can cause a flare of psoriasis or trigger onset
Candida albicans (thrush)
Human immunodeficiency virus (HIV) increases the severity of psoriasis
Staphylococcal skin infections (boils) can cause a flare of psoriasis
Viral upper respiratory infections can cause a flare of psoriasis

Question 7

What are other associated triggers (besides infection, obesity, etc.)?

Answer 7

Drugs (lithium, NSAIDs, beta-blockers, anti-malarials, interferons)
Cold, dry weather
Skin trauma (cuts, bruises, burns, bumps, vaccinations, tattoos - "Koebner phenomenon")

Question 8

Describe the Koebner phenomenon

Answer 8

Occurs in almost half of those who already have psoriasis
Occurs within 7 to 14 days of injury to the dermis layer
Increased risk when psoriatic lesions are already present
Injury can be caused by: physical injury (insect bites, cuts, scrapes, tattoos), chemical burns (chemicl irritants), excessive rubbing (chafing, shaving), sunburns, allergic reactions (adhesives, contact dermatitis)

Question 9

What are the physiological roles of the skin?

Answer 9

Barrier to elements and pathogens
Thermo-regulator protecting the body from excessive heat loss or overheating
Protects from UV radiation
Wound repair and regeneration
Synthesizes vitamin D

Question 10

What are the three layers of the skin?

Answer 10

Epidermis (physical barrier/protects the skin from the environment)
Dermis (layer of connective tissue containing blood vessels)
Hypo-dermis (provides structural integrity to the skin)

Question 11

Describe the role of the epidermis

Answer 11

Provides a physical barrier
Ranges in thickness from 0.4 to 1.5 mm (depending on the location on the body)
Continually renews every 4 to 6 weeks
Outermost layer is the stratum corneum

Question 12

What are the different cell types within the epidermis

Answer 12

Keratinocytes
Melanocytes
Langerhans cells
Merkel cells

Question 13

Describe the keratinocytes

Answer 13

Keratinocytes (80-85%) produce keratin which is the key structural material making up the outer layer (integrity) of the human skin (stratum corneum). They are also the key strutural component of hair and nails. They move from the basal cell layer to the surface (also called basal cells). They differentiate on transit from basal cell to stratum corneum (loose nuclei and cytoplasmic organelles).

Question 14

Describe the melanocytes

Answer 14

Responsible for pigment production (5%)

Question 15

Describe the Langerhans cells

Answer 15

They are responsible for detecting, attacking, neutralizing and eliminating foreign bodies (2-5%)

Question 16

Describe the merkel cells

Answer 16

They are involved in the function of touch (6-10%)

Question 17

What is the current hypothesis regarding psoriasis as a T-cell mediated autoimmune disease?

Answer 17

Unknown skin antigens stimulate immune responses.

This leads to impaired differentiation and hyper-proliferation of keratinocytes

Question 18

What are T cells/T lymphocytes?

Answer 18

White blood cells that protect the body from “invaiders” called antigens. They are normally found in small numbers in the skin

Question 19

What results of the activation of T cells?

Answer 19

Activation of T cells (Th1 and Th17 subtypes) via antigen presenting cells (APCs) results in the release of inflammatory mediators such as cytokines and chemokines that drive the immune system induced repsonse

Question 20

How does T cell infiltration affect the skin?

Answer 20

Following a stimulus (antigen presentation) T cells (Th1 and Th17) and dendritic cells become activated. Activation leads to release of cytokines, chemokines and other mediators of inflammation. The epidermis is infiltrated by activated T cells. Activated T cells induce keratinocyte proliferation. This results in faster maturation than normal (3-5 days vs >30 days) thereby reducing differentiation which promotes build up of skin plaques. Plaques contain 30x more keratinocytes than healthy skin

Question 21

What are the four main pathogenic changes associated with psoriasis?

Answer 21

1. Abnormal keratinocytes proliferation and differenation = epidermal thickening
2. Abnormal angiogenesis (formation of new blood vessels) & increased capillary permeability = bright erythema
3. Accumulation of parakeratotic keratinocytes and neutrophils in stratum corneum = silvery psoriatic scales
4. Elongated “rete ridges”

Question 22

What are characteristic psoriatic changes?

Answer 22

Thickened stratum corneum, elongated rete & angiogenesis

Question 23

What are the most frequently experienced symptoms of psoriasis in order of frequency?

Answer 23

Scaling, itching, skin redness, tightness of skin, bleeding, burning sensation, fatigue

Question 24

What are the different types of psoriasis?

Answer 24

Chronic plaque (psoriasis vulgaris)
Guttate
Flexural
Erythrodermic
Pustular
Local forms (palmoplantar, scalp, nail)

Question 25

Describe guttate "drop" psoriasis

Answer 25

Also known as "eruptive psoriasis" is a type of psoriasis that presents as a small (0.5-1.5 cm in diameter) lesions over the upper trunk and proximal extremities; it is found frequently in young adults. It is classically triggered by a bacterial infection, usually an upper respiratory tract infection

Question 26

Describe the onset of guttate psoriasis?

Answer 26

For some people it starts as a throat infection, or strep throat. After the throat infection has cleared up the person can feel fine for several weeks before noticing the appearance of red spots. They appear small at first, like a dry red spot which is slightly itchy.

Question 27

What happens when the plaques of guttate psoriasis?

Answer 27

When scratched or picked the top layer of dry skin is removed, leaving dry, red skin beneath with white, dry areas marking where flakes of dry skin stop and start.. In the weeks that follow the spots can grow to as much as an inch in diameter

Question 28

Where does guttate psoriasis?

Answer 28

It occurs on any part of the body, particularly the legs, arms, torso, eyelids, back, bottom, bikini-line and neck. Generally the parts of the body the most affected are seen on the arms, legs, back and torso

Question 29

Describe flexural psoriasis

Answer 29

It is a non-infectious auto-immune disease, caused by the activation of T cells within the skin. It is a form of psoriasis found in the armpits, groin, under the breasts and in other flexion creases such as those around the genitals and buttocks. It often results in the redness and inflammation, with scaly, dead skin on the surface

Question 30

Describe the appearance of flexural psoriasis

Answer 30

Smooth skinny inflamed patches | Thin, minimally scaly, raw, tender, itchy, well defined plaques

Question 31

Where does flexural psoriasis?

Answer 31

Occurs on flexor surfaces | Armpits, groin, under the breasts, skin folds of the buttocks

Question 32

Describe erythrodermic psoriasis

Answer 32

It is a particularly inflammatory form of psoriasis that often affects most of the body surface. It may occur in association with von Zumbusch pustular psoriasis. It is rare type of psoriasis, occurring once or more during the lifetime of 3 percent of people who have psoriasis. This means the lesions are not clearly defined. Widespread, fiery redness and exfoliation of the skin characterize this form. Severe itching and pain often accompanies it

Question 33

Why does erythrodermic psoriasis occur?

Answer 33

It may occur because of drug reactions, trauma, emotional stress or illness. It may evolve slowly from chronic plaque psoriasis or appear as eruptive phenomenon

Question 34

Where does erythrodermic psoriasis occur?

Answer 34

Covers about 75-90% of the skin surface

Question 35

What are complications associated with erythrodermic psoriasis?

Answer 35

Infections, malabsorption and anemia

Question 36

Describe pustular psoriasis

Answer 36

It is an uncommon form of psoriasis. It is clearly defined, raised bumps that are filled with a white, thick fluid composed of white blood cells, also known as pus. The skin under and around these bumps is red. Although pus is often as sign of infection, there is no evidence that infection plays any role in pustular psoriasis

Question 37

Describe the appearance of pustular psoriasis. Where is it localized

Answer 37

White pustules surrounded by red skin (blisters of non infectious pus) Intense itching and burning Typically localized to the hands and feet

Question 38

What is the most common form of psoriasis?

Answer 38

Chronic plaque/Psoriasis vulgaris (80-90% of patients)

Question 39

How does psoriasis vulgaris appear?

Answer 39

Red/pink, scaly plaques at least 0.5 cm in diameter Raised, well defined flat topped plaques with sharp borders (symmetrical) Typically covered with silvery white scales that constantly shed

Question 40

Where is psoriasis vulgaris typically located?

Answer 40

Arms, legs, elbows, knees, gentialia, lower back and buttocks Occurs on the extensor surfaces

Question 41

Describe palmo-plantar psoriasis

Answer 41

Can be hyperkeratotic or pustular Limited to palms of hands and soles of feet Can be quite difficult to treat Possibly aggravated by trauma

Question 42

Describe scalp psoriasis

Answer 42

Difficult to differentiate between dandruff and seborrhea Can occur alone or with other psoriasis types Mild form appears as dry, fine scales whereas more severe forms appear as thick, crusted plaques

Question 43

Where is scalp psoriasis typically located?

Answer 43

Along the hairline of the scalp | Forehead, back of neck and around the ears

Question 44

Describe nail psoriasis

Answer 44

May be present in patients with any type of psoriasis Can take several forms: Pitting (discrete, well-circumscribed depressions on nail surface) Subungual hyperkeratosis (silvery white crusting under free edge of nail with some thickening of nail plate) Onycholysis (nail separates from nail bed at free edge) "Oil-drop sign" (pink/red colour change on nail surface

Question 45

What is nail psoriasis typically associated with?

Answer 45

Smoking

Question 46

What are co-morbid conditions

Answer 46

Inflammatory bowel disease (Crohn's, ulcerative colitis) Type 2 diabetes Cardiovascular disease (increased risk; stroke atherosclerosis, heart attacks) Obesity Depression (significant; affects patients quality of life)

Question 47

Describe psoriatic arthritis

Answer 47

May appear 7 to 10 years after psoriasis appears on the skin Affects patients most often with nail and scalp psoriasis between the ages of 30 to 50 years Can affect up to 30% of individuals with psoriasis Appearance: joint deformity, red, warm and inflammation Location: distal joint of fingers, wrists, ankles, knees, back and neck

Question 48

What are the general goals of treatment?

Answer 48

Tailor management to individual and address both medical and psychological aspects Improve quality of life Achieve long-term remission and disease control Minimize drug toxicity Evaluate and monitor efficacy and suitability of individual treatments Remain flexible and respond to changing needs

Question 49

What are the measures of treatment success?

Answer 49

Clearance: disease is controlled with no signs or symptoms Control: response to therapy that satisfies both the patient and the physician Remission: disease is controlled for an extended time period either partially or completely without treatment other than routine skin care

Question 50

What are the measures of treatment failure?

Answer 50

Exacerbation: worsening of the disease Flare: exacerbation occurring while on therapy and the condition is different than the original disease (size of area covered, more severe) Rebound: exacerbation of the condition due to treatment discontinuation (usually within 3 months of stopping treatment)

Question 51

What are potential trigger factors that should be reduced/eliminated for treatment?

Answer 51

Stress, smoking, alcohol, trauma, drugs, infections

Question 52

What are general topical treatment measures for all plaque psoriasis that should be used with or without other topical/systemic treatments?

Answer 52

Emollients/moisturizers (protective film to lessen dehydration) Keratolytics (ex. urea, salicylic acid, lactic acid)

Question 53

Describe emollients/moisturizers as a general topical treatment measure for psoriasis

Answer 53

Prefers creams or ointments to lotions (increased viscosity, lipid richness and "staying power") Hydration of stratum corneum = enhanced penetration of corticosteroid products Includes petrolatum, ointment/creams, bath oils, etc.

Question 54

Describe keratolytics as a general topical treatment measure for psoriasis

Answer 54

Soften plaques by promoting cellular desquamation | Also help to promote corticosteroid penetration

Question 55

What are treatment options for psoriasis?

Answer 55

``` Topical agents (most commonly used) Systemic therapy (moderate to severe conditions) Phototherapy (UVB light, which decreases cells involved in psoriasis pathogenesis) ```

Question 56

What are topical treatment options for psoriasis?

Answer 56

Corticosteroid (anti-inflammatory, reduces production of cytokines, reduces scaling and itching) Vitamin D3 analogues (inhibit proliferation of keratinocytes and reduces inflammation)

Question 57

What are systemic treatment options for psoriasis?

Answer 57

Traditional: methotrexate, which decreases the rate of proliferation of keratinocytes), and/or cyclosporine, which inhibits activation of T cells Biologics (target the immunological causes) Systemic treatments are usually only used when psoriasis covers most of the body and patient doesn't respond to topical treatment

Question 58

How should treatment be planned?

Answer 58

It should be based on the severity of the disease (assessed using several different tools) Determine previous therapies (success/failure?) Treatment should be in a step-wise manner Therapies are often combined to attain desired outcomes Consider patient feasibility (i.e., phototherapy = 3-5x weekly) Remember psychological aspect of illness too