Case 8- psoriasis and eczema

Question 1

Psoriasis

Answer 1

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

Question 2

Who does psoriasis effect?

Answer 2

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

Question 3

What causes psoriasis- vague

Answer 3

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.

Question 4

Mechanism of action of psoriasis

Answer 4

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

Question 5

When does psoriasis present?

Answer 5

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

Question 6

What does psoriasis effect?

Answer 6

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.

Question 7

The lesions of psoriasis

Answer 7

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.

Question 8

Psoriasis changes associated with nails

Answer 8

• Pitting of the nail
• Yellowing of the nail
• Onycholysis- separation of the nail from the nail bed.

Question 9

Guttate psoriasis

Answer 9

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.

Question 10

Clinical consequences of psoriasis

Answer 10

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

Question 11

Conditions psoriasis is associated with

Answer 11

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

Question 12

Eczema

Answer 12

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.

Question 13

How do allergens get through the skin

Answer 13

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

Question 14

Mechanism of eczema

Answer 14

• 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

Question 15

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

Answer 15

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.

Question 16

The two factors that lead to eczema

Answer 16

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

Question 17

Eczema- skin barrier failure

Answer 17

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

Question 18

Eczema- role of immune system

Answer 18

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

Question 19

Eczema triggers

Answer 19

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.

Question 20

Distribution of eczema in babies

Answer 20

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

Question 21

Distribution of eczema in children

Answer 21

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

Question 22

Distribution of eczema in adults

Answer 22

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

Question 23

How eczema presents in darker skin

Answer 23

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

Question 24

Appearance of skin in eczema

Answer 24

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).

Question 25

Clinical effects of eczema

Answer 25

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.

Question 26

Life style changes and eczema

Answer 26

• 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

Question 27

Infected eczema

Answer 27

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.

Question 28

What diseases are eczema associated with?

Answer 28

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

Question 29

Eczema herpeticum

Answer 29

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.

Question 30

Cure for psoriasis

Answer 30

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

Question 31

First line psoriasis treatment

Answer 31

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.

Question 32

Psoriasis- Emollients

Answer 32

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

Question 33

Psoriasis- steroids

Answer 33

Hydrocortisone, betamethasone - reduces inflammation

Question 34

Psoriasis - vitamin D analogues

Answer 34

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

Question 35

Psoriasis- coal tar

Answer 35

Reduces inflammation and scale

Question 36

Psoriasis- side effects of steroids

Answer 36

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

Question 37

Criteria for secondary care (dermatologist for psoriasis

Answer 37

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

Question 38

Psoriasis- 2nd and 3rd line treatment

Answer 38

Specialist and should only be started in hospital by dermatologists

Question 39

Psoriasis- main 2nd line treatment

Answer 39

• 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.

Question 40

Psoriasis 3rd line treatment

Answer 40

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.

Question 41

Eczema treatment

Answer 41

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.

Question 42

Eczema- emollients

Answer 42

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.

Question 43

Eczema- Topical steroids

Answer 43

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

Question 44

What steroids are used in areas of thin skin

Answer 44

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

Question 45

What steroids are used in areas of thicker skin

Answer 45

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

Question 46

Eczema- when to refer to secondary care (dermatology)

Answer 46

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

Question 47

Eczema- treatment started in secondary care

Answer 47

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