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Pathophysiology 2 > March 13 - Psoriasis > Flashcards

March 13 - Psoriasis Flashcards

1
Q

Describe psoriasis

A

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

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2
Q

What is the mean age of onset of psoriasis?

A

Mean age: approximately 23-37 years

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3
Q

What is the current theory regarding the age of onset?

A 
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)
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4
Q

Describe the etiology/risk factors of psoriasis

A

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

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5
Q

What are some external predisposing factors?

A 
Obesity
Alcohol consumption
Smoking
Stress
Viral/bacterial infections (e.g., HIV) - can predispose to disease onset or trigger relapse
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6
Q

Describe the link between infection and psoriasis

A

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

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7
Q

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

A 
Drugs (lithium, NSAIDs, beta-blockers, anti-malarials, interferons)
Cold, dry weather
Skin trauma (cuts, bruises, burns, bumps, vaccinations, tattoos - "Koebner phenomenon")
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8
Q

Describe the Koebner phenomenon

A

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)

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9
Q

What are the physiological roles of the skin?

A 
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
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10
Q

What are the three layers of the skin?

A

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)

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11
Q

Describe the role of the epidermis

A

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

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12
Q

What are the different cell types within the epidermis

A

Keratinocytes
Melanocytes
Langerhans cells
Merkel cells

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13
Q

Describe the keratinocytes

A

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).

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14
Q

Describe the melanocytes

A

Responsible for pigment production (5%)

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15
Q

Describe the Langerhans cells

A

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

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16
Q

Describe the merkel cells

A

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

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17
Q

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

A

Unknown skin antigens stimulate immune responses.

This leads to impaired differentiation and hyper-proliferation of keratinocytes

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18
Q

What are T cells/T lymphocytes?

A

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

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19
Q

What results of the activation of T cells?

A

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

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20
Q

How does T cell infiltration affect the skin?

A

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

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21
Q

What are the four main pathogenic changes associated with psoriasis?

A
  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”
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22
Q

What are characteristic psoriatic changes?

A

Thickened stratum corneum, elongated rete & angiogenesis

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23
Q

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

A

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

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24
Q

What are the different types of psoriasis?

A 
Chronic plaque (psoriasis vulgaris)
Guttate
Flexural
Erythrodermic
Pustular
Local forms (palmoplantar, scalp, nail)
25
Q

Describe guttate “drop” psoriasis

A

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

26
Q

Describe the onset of guttate psoriasis?

A

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.

27
Q

What happens when the plaques of guttate psoriasis?

A

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

28
Q

Where does guttate psoriasis?

A

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

29
Q

Describe flexural psoriasis

A

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

30
Q

Describe the appearance of flexural psoriasis

A

Smooth skinny inflamed patches

Thin, minimally scaly, raw, tender, itchy, well defined plaques

31
Q

Where does flexural psoriasis?

A

Occurs on flexor surfaces

Armpits, groin, under the breasts, skin folds of the buttocks

32
Q

Describe erythrodermic psoriasis

A

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

33
Q

Why does erythrodermic psoriasis occur?

A

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

34
Q

Where does erythrodermic psoriasis occur?

A

Covers about 75-90% of the skin surface

35
Q

What are complications associated with erythrodermic psoriasis?

A

Infections, malabsorption and anemia

36
Q

Describe pustular psoriasis

A

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

37
Q

Describe the appearance of pustular psoriasis. Where is it localized

A

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

38
Q

What is the most common form of psoriasis?

A

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

39
Q

How does psoriasis vulgaris appear?

A

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

40
Q

Where is psoriasis vulgaris typically located?

A

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

41
Q

Describe palmo-plantar psoriasis

A

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

42
Q

Describe scalp psoriasis

A

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

43
Q

Where is scalp psoriasis typically located?

A

Along the hairline of the scalp

Forehead, back of neck and around the ears

44
Q

Describe nail psoriasis

A

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

45
Q

What is nail psoriasis typically associated with?

A

Smoking

46
Q

What are co-morbid conditions

A

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)

47
Q

Describe psoriatic arthritis

A

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

48
Q

What are the general goals of treatment?

A

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

49
Q

What are the measures of treatment success?

A

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

50
Q

What are the measures of treatment failure?

A

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)

51
Q

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

A

Stress, smoking, alcohol, trauma, drugs, infections

52
Q

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

A

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

53
Q

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

A

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.

54
Q

Describe keratolytics as a general topical treatment measure for psoriasis

A

Soften plaques by promoting cellular desquamation

Also help to promote corticosteroid penetration

55
Q

What are treatment options for psoriasis?

A 
Topical agents (most commonly used)
Systemic therapy (moderate to severe conditions)
Phototherapy (UVB light, which decreases cells involved in psoriasis pathogenesis)
56
Q

What are topical treatment options for psoriasis?

A

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

57
Q

What are systemic treatment options for psoriasis?

A

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

58
Q

How should treatment be planned?

A

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

Pathophysiology 2 (15 decks)

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