Psoriasis

Question 1

Do we fully understand the pathophysiology of psoriasis? Discuss.

Answer 1

The pathogenesis of psoriasis is unclear. There are a multitude of factors that can contribute to this immune-mediated inflammatory disease.
-Genetic factors
-Immune factors and inflammatory cytokines
-Environmental factors.

Question 2

Explain what abnormal skin processes occur that contribute to redness, inflammation and skin thickening in psoriasis?

Answer 2

Inflammatory processes in the dermis (proliferation and dilation of blood vessels), hyperproliferation (increased cell turnover), abnormal maturation of cells in the epidermis and a delayed shedding of the skin cells.

Question 3

What are some signs and symptoms of psoriasis?

Answer 3

Psoriasis usually presents as:
-well defined
-raised red patches or plaques with a thick silvery scale.
-usually lifelong and fluctuating in extent and severity.
-can occur in the nails -> thick, rigid and pitted.

Question 4

What are the five classifications of psoriasis?

Answer 4

Plaque, scalp, nail, gluttate and flexural

Question 5

Discuss plaque psoriasis (most common type:
-Presentation
-Location

Answer 5

Well-demarcated, pink plaques with silvery scale, can be single or numerous lesions.
Often asymptomatic but can be itchy.
Common sites:
Outside of elbows, knees, sacrum, and lower back.

Question 6

Discuss scalp psoriasis:
-Presentation
-Location

Answer 6

-Generally presents as thick patches that can cover the entire scalp and may extend slightly beyond the hairline (facial psoriasis)
-May cause temp mild hair loss in severe cases
-may be first/only site, or coexist with other psoriasis.

Question 7

Discuss nail psoriasis:
-Presentation
-location
-common ailment alongside

Answer 7

-Presents as: pitting, yellowing and ridging on nails, Onycholysis sometimes
-Often affects multiple nails compared to 1 or 2 as seen with tinea (tinea also generally doesn’t affect fingernails just toes)
-Location: arises from the nail matrix.
-Commonly seen with:
Most patients also have chronic plaque psoriasis and or psoriatic arthritis.

Question 8

Discuss Guttate Psoriasis:
-Presentation
-Location
-Demographic

Answer 8

-Shower of red, scaly tear drops on the skin
-Usually on trunk, upper arms and thighs.
-Scaly may be less noticeable than in other psoriasis forms.
-May be triggered by Strep
-Occurs at any age but most often in teenagers and y/adults
-Spontaneous resolution

Question 9

Discuss Flexural Psoriasis:
-Presentation
-Location

Answer 9

• Localised to body folds and genitals
  -Appearance can vary due to different moisture environments of skin folds.
  -Sometimes called inverse psoriasis
  -Smooth, well defined - often has little scale but may be shiny
  -May be colonised by Candida species.

Question 10

What is the name of the class of psoriasis that is considered a medical emergency?

Answer 10

Generalised Pustular Psoriasis - very rare, medical emergency.

Question 11

Describe how palmoplantar pustulosis presents:

Answer 11

Presents as a crop of pustules, red, scaly, thickened skin localised to the palms and soles.

Question 12

What are some differential features between seborrhoeic dermatitis and scalp psoriasis?

Answer 12

They will have a very similar appearance, especially in how they present around the scalp and ears. Overtime, some patients may progress from dermatitis to psoriasis,
Key distinguishing feature -> psoriasis won’t respond to the antifungal treatments used for seborrhoeic dermatitis.

Question 13

Psoriasis cycles between acute flares and remissions. What are the treatment goals for psoriasis?

Answer 13

-Induce remission
-reduce extent and severity of psoriasis
-relieve symptoms (pain and itch).

• Also consider psychological impacts and other comorbidities.

Question 14

Discuss what Keratolyitcs are and what forms they come in, and an example.

Answer 14

Keratolytics are compounds that breakdown the outer layer of the skin and can decrease the thickness of psoriatic plaques.
-Example = salicylic acid
-Can be cream/ointment etc
-Varied strengths (2-6% used for psoriasis- applied thin layer 2-3 x d)

Question 15

What is a counselling point for keratolytic use in psoriasis?

Answer 15

-May cause stinging or irritation to surrounding skin.

Question 16

Discuss Coal Tar Preparations:
What they do, and
Avhow they are used?

Answer 16

• Coal Tar (crude) or LPC (liquid coal tar)
  -1% crude coal tar is equivalent to 5% LPC
  -Can be compounded to make creams, ointments and other formulations (0.5-6%)
  -THOUGHT to reduce epidermal thickness, antipruritic, may be weakly antiseptic.

Question 17

Important counselling points for coal tar:

Answer 17

The preparation (cream etc..) may smell funny and it can also stain clothes, skin and fine hair.
Avoid contact with eyes - mild irritation.
Use at night (and if using adjunct treatment i.e. corticosteroids- use these in morning)

Question 18

What action do steroid creams have in treating psoriasis?

Answer 18

-Anti-inflammatory
-Antimitotic (reduce skin turn over)
-Most common in initial control of psoriasis.

Question 19

What are some key counselling points for specialist prescribed Dithranol?

Answer 19

-Apply thin layer to plaques only. Avoid sensitive areas.
-Keep in a dark place for storage (colour change to brown/purple = expired)
-Will stain - use gloves
-THOUGHT to be an antimitotic, exact MOA unknown.
-Time on skin depends on strength.

Question 20

Name a vitamin D analogue, what it is often combined with and called, and key counselling points for patient.

Answer 20

Calcipotriol (000.5%)
-Available in combo w/ betamethasone 0.05% (Daviobet and Enstilar foam)
-Avoid sunlight, and application on face or delicate skin (folds)
-Apply 1d for up to 4 weeks.

Question 21

Discuss Calcineurin inhibitors:
What is the MOA?
What are they used for?
Provide an example.

Answer 21

• Anti-inflammatory. Inhibits calcineurin, thus blocking T cell proliferation and preventing the release of inflammatory cytokines.
• Use for atopic dermatitis (eczema)
• Elidel (Pimecrolimus)