Case 8- psoriasis and eczema Flashcards

1
Q

Psoriasis

A

A chronic inflammatory skin condition characterised by scaly plaques (areas of thickened skin). The most common psoriasis is chronic plaque psoriasis (90%) you also have guttate psoriasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Who does psoriasis effect?

A

Effects 2-4% of the population with equal amounts of males and females. More common in Caucasians but effects any race

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What causes psoriasis- vague

A

The pathophysiology is complex and not fully understood. There is a strong genetic element but also some environmental triggers i.e. stress, smoking and certain medication. The triggers can lead to a flare up. It is an autoimmune response which results in hyperproliferation of keratinocytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mechanism of action of psoriasis

A
  1. Stimulus: genetic susceptibility/environmental trigger.
  2. T cells and dendritic cells infiltrate the skin
  3. There is release of pro-inflammatory mediators i.e. TNF, IL-7
  4. Activation and proliferation of keratincoytes
  5. Keratinocytes are proliferating more quickly and move up through the epidermis in 3-5 days, normally it takes 21 days.
  6. This results in a thick epidermis and scaly skin as it flakes of
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When does psoriasis present?

A

It presents for the first time in people under 35 but is uncommon in children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does psoriasis effect?

A

It has a relapsing course and is quite persistent but can improve with treatment. It tends to affect the scalp and extensor surfaces (particularly knees and elbows), it is usually symmetrical.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The lesions of psoriasis

A

The lesions themselves are elevated areas of thickened skin known as plaques. They are usually well-demarcated and circular/oval in shape. They can be red-pink or dark brown/purple in colour. They have an overlying white, silvery or grey scale. They are usually very itchy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Psoriasis changes associated with nails

A
  • Pitting of the nail
  • Yellowing of the nail
  • Onycholysis- separation of the nail from the nail bed.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Guttate psoriasis

A

Characterised by multiple small scaly plaques, looking like multiple small teardrops on the body. Mostly affects the trunk, upper arms and thighs. It often 2-3 weeks after a streptococcal infection of the upper respiratory tract i.e. tonsilitis, pharyngitis. It usually spontaneously resolves after 3-4 months, although another flare-up can occur following another streptococcal infection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Clinical consequences of psoriasis

A

It is associated with significant psychosocial difficulty. Quality of life can be severly affected by sever itching, dry/peeling skin and side effects of treatment. The lesions can be widespread leading to patients becoming self-conscious about their appearance, this can lead to anxiety and depression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Conditions psoriasis is associated with

A

Psoriatic arthiritis, inflammatory bowel disease, metanolic syndromes (central obesity, hypertension, insulin resistance).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Eczema

A

Also known as atopic dermatitis, is a chronic inflammatory skin condition that is characterised by dry, itchy and inflammed areas of skin. Very common in children, 80% of cases present before 5. It has a complex pathophysiology with no single known cause. Overall it is a result of a weakened skin barrier and predisposition torwards allergic inflammation. This predisposition is atopy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do allergens get through the skin

A

Through the small pores of the skin, this triggers a hypersensitivity reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Mechanism of eczema

A
  • An environmental allergen gets through the skin barrier
  • The allergen gets picked up by an antigen presenting cell (dendritic)
  • This activates a T helper cell which stimulates the B cell to produce IgE antibodies that are specific to the allergen.
  • The IgE antibody binds to a mast cell or basophil, resulting in sensitisation.
  • When there is a second exposure to the allergen, the allergen can bind to the IgE antibodies on the surface of the mast cell/basophil.
  • This binding causes the mast cell/basophil to release pro-inflammatory molecules i.e. histamine
  • This causes dilation of blood vessels (redness) and increased permeability of the skin barrier so more allergens can enter and water is lost from the skin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Eczema- what happens when water is lost from the skin?

A

The water loss causes dry skin which is very itchy, when the patient itches their skin they further damage and breakdown the skin barrier. More allergen is able to get in and the cycle continues.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The two factors that lead to eczema

A

1) Skin barrier failure
2) Role of the immune system
Unclear whether the main cause of eczema is the imbalance in the immune system or the reduced production of fiaggrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Eczema- skin barrier failure

A

A genetic mutation leads to less production of the protein filaggrin (needed to help create corneocytes and the lipid matrix from keratinocytes). This leads to a failure of the skin barrier as its more permeable so more allergens are able to enter and provoke an immune response. More water is also able to leave the skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Eczema- role of immune system

A

Some patients have increased levels of T helper cells due to a genetic mutation. This causes a stronger immune response to allergens so increases inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Eczema triggers

A

Eczema can be stable and then flare up again, triggers include: Shampoos, soaps, shower gels, dust mites, pollens, abrasive fabrics, extremes of temperatue and humidity, stress.

20
Q

Distribution of eczema in babies

A

Lesions are widely distributed over surfaces of arms, legs and face

21
Q

Distribution of eczema in children

A

Tends to affect flexor surfaces of elbows, knees, eyelids and neck

22
Q

Distribution of eczema in adults

A

Tends to be less widespread, affecting mostly flexor surfaces and hands

23
Q

How eczema presents in darker skin

A

It will appear hyperpigmented instead if red. This is because the inflammation caused increased melanin production from melanocytes.

24
Q

Appearance of skin in eczema

A

The skin appears very dry, itchy and red. Constant scratching/rubbing of the skin causes it to become lichenfied (thickened). This is more common is older children/adults as the scratching has occurred over a longer time period. Well-demarcated, there are circular/oval plaques (elevated areas of thickened skin).

25
Q

Clinical effects of eczema

A

Can have severe psychosocial effects on the patient. Rashes are often on highly visible areas of skin leading to poor self-image and low self-esteem. Children can be bullied leading to social isolation and poor school performance. The severe itch can impair sleeping leading to sleep deprivation and associated emotional problems such as impaired thinking.

26
Q

Life style changes and eczema

A
  • May be restricted in what types of clothing can be comfortably worn
  • May be restricted in owning certain pets (if trigger flare-ups)
  • Can impact on activities such as swimming/outdoor exercise
27
Q

Infected eczema

A

Patients are at risk of developing bacterial infections of their eczema, as scratching leads to the breakdown of the skin barrier, allowing bacteria to enter. The lesions usually become crusted, weepy and can be surrounded by areas of cellulitis.

28
Q

What diseases are eczema associated with?

A

Other atopic diseases: asthma, hay fever. Can be associated with depression

29
Q

Eczema herpeticum

A

Complication of eczema due to a viral infection, usually with herpes simplex virus 1 or 2. Causes clusters of painful, itchy blisters. Can have punched out erosions (circular, ulcerated lesions) as well as fever, tiredness and feeling unwell. It can progress with a superimposed bacteria infection and become very serious so requires urgent admission to hospital.

30
Q

Cure for psoriasis

A

Can be improved with treatment but there is no cure, so patients often have relapses

31
Q

First line psoriasis treatment

A

Topical treatments, they are usually prescribed and monitored by GP’s. Emollients and vitamin D analogues are useful in long-term management. Steroids are useful for short term use in flare ups.

32
Q

Psoriasis- Emollients

A

Diprobase, E45- provides moisture to the skin, reduces itch

33
Q

Psoriasis- steroids

A

Hydrocortisone, betamethasone - reduces inflammation

34
Q

Psoriasis - vitamin D analogues

A

Calcipotriol - helps normalise keratinocyte proliferation (reducing thickness/scaliness of plaques)

35
Q

Psoriasis- coal tar

A

Reduces inflammation and scale

36
Q

Psoriasis- side effects of steroids

A

Avoid prolonged use of steroids as they can cause side-effects i.e. thinning of skin, bruising, acne. For prolonged use they can get absorbed into the blood stream causing internal side effects like increased infection risk, weight gain, hyperglycaemia

37
Q

Criteria for secondary care (dermatologist for psoriasis

A

The disease is very extensive, it is not controlled by topical treatment, it has a significant impact on the patients wellbeing.

38
Q

Psoriasis- 2nd and 3rd line treatment

A

Specialist and should only be started in hospital by dermatologists

39
Q

Psoriasis- main 2nd line treatment

A
  • Phototherapy (using UV radiation) - helps stop hyperproliferation of keratinocytes. Side effects include risk of sunburn, skin ageing, and skin cancer.
  • Non-biological oral medications e.g. methotrexate - work by suppressing the immune system.
40
Q

Psoriasis 3rd line treatment

A

3rd line treatment is biological therapies i.e. infliximab. They are very powerful immunosuppressants that target specific components of the immune system. Usually given as injections under the skin or infusions into a veins. The patient has a higher risk of infection. Only used in severe disease.

41
Q

Eczema treatment

A

60-70% of cases are resolved by early teens but some are more persistent. Patients should avoid contact with known triggers. Counselling offered to those with psychosocial difficulties. Treatment involves regular emollients and topical steroids for flare ups.

42
Q

Eczema- emollients

A

Should be applied 3-4 times a day, even when skin is clear. Helps provide moisture to skin, restores skin barrier function and prevent water loss.

43
Q

Eczema- Topical steroids

A

Used for managing flare-ups as it reduced the immune response in that area of the skin. Used only for flare ups due to side effects. Different strength of steroids used depending on the area of skin affected

44
Q

What steroids are used in areas of thin skin

A

Face and in babies- mild steroids i.e. hydrocortisone

45
Q

What steroids are used in areas of thicker skin

A

Limbs, trunk, scalp, any lichenidies area- more potent steroids are used i.e. betamethasone

46
Q

Eczema- when to refer to secondary care (dermatology)

A

For severe cases not managed by emollients/steroids, or if there is a sever psychosocial impact on the patient.

47
Q

Eczema- treatment started in secondary care

A
  • Wet wraps - bandages wrapped over emollient and steroid. Help to cool and moisturise skin and prevent scratching.
  • Phototherapy
  • Oral immunosuppressants