Psoriasis

DR. HADAF ALJUNAIYEH

Psoriasis

A common inflammatory disease of skin
Chronic relapsing condition
Unpredictable course
Has a great impact on patient’s life





Emotional impact: patients with psoriasis often display: 1-Depression 2- Feeling of unattractiveness 3-Fear about future & prognosis

Wrongly assumed to be contagious

Embarrassment in public places & hair dressers

Epidemiology

Prevalence is 2-3 % of the population
Ranging between 0.91% in the US to 8.5% in Norway
Equal male & female ratio
Estimated incidence 60 per 100000 per year

Age of onset

Mean age of onset 23-37, with 2 peaks with possible genetic associations:
1- Early onset 16-22 years: more severe & aggressive presentation & possible first degree relative affection
2_ Late onset 57-60 years: milder & absent first degree relative involvement

pathogenesis

Two key pathophysiological aspects:
1) Increased rate of keratincytes proliferation+ parakeratosis
2) Large inflammatory cell infiltrate as polymorphs, T cells, & others.
Familial component, many relatives affected, increased in successive generations, multifactorial inheritance

* Psoriasis is a T cell mediated auto-immune disease *

Current hypothesis:
Unknown skin antigen stimulate immune response
Antigen-specific memory T cells are primary mediators
Leading to impaired differentiation & hyper proliferation of keratinocytes

Triggering factors in susceptible patients

1-Infection:
β hemolytic strept. throat infection
precede guttate psoriasis.

2-Trauma: positive Kobner’s phenomenon

4- Drugs:

antimalarials, lithium,
β blockers worsen
psoriasis, stopping
steroids causes
rebound of the rash.

Metabolic

5-

6-Hormonal:

as in pregnancy

Role of obesity

Doubles the risk of psoriasis
BMI correlate with psoriasis severity

Clinical features

• Well-demarcated, sharply defined
• erythematous (salmon pink)
• plaques covered by silvery
• white scales
• Usually symmetrical

Scalp psoriasis

Koebner’s phenomenon

The commonest complaint isscaling

scaling

Followed by:

Itching

Third is

Redness of skin

Next is

Tightness of skin

Bleeding is the 5th

Burning the 6th complaint

Last is

• Fatigue
•

Clinical types of psoriasis

Psoriasis vulgaris

Chronic plaque psoriasis
The commonest type 85%
Can be extensive

Guttate psoriasis

Numerous small lesions about 1cm
Usually less scaly
Trunk & proximal limbs
Usually patients less than 30
Often preceded by strept URTI.

Flexural psoriasis

In body folds
Less scaly
Often miss DX if no
other signs of psoriasis






Napkin psoriasis
2-8 months old babies
disappear by topical treatment
Might reappear in adult life.

Erythrodermic psoriasis

Uncommon
More than 90% of skin surface
Can evolve from chronic or eruptive
Fever, hypo & hyperthermia,
dehydration
Complications: Heart failure,
infections, malabsorption, & anaemia

Pustular psoriasis

1- Localized:
more common
On palms & soles
2- Generalized:
Associated with fever

Palmoplantar psoriasis

Can be hyperkeratotic or
pustular
Difficult to distinguish from
chronic eczema or tinea
May be aggravated by trauma

Psoriatic arthritis

In 5-10% of psoriatics
Rare before age 20
Rheumatoid factor (–ve) arthritis
5 types either peripheral or central, often
overlap

Nail changes in psoriasis

1) Distal onycholysis.
2) Random pitting from parakeratosis of proximal matrix.
3) Oil spots which are yellow areas of subungual parakeratosis
4) Salmon patches due to nail bed psoriasis.
5) Subungual hyperkeratosis resembling onychomycosis.

Nail psoriasis

Treatment

Reassurance, explanation are vital
Psoriasis is not contagious
No cure, so the aim is to induce remission or making it more tolerable
Spontaneous remission in 50% of cases
Quit smoking

Three main modalities of treatment

Topical
Physical
systemic

calcipotriol

vitamin D agonist, only reduce thickness & scaling of the plaques
It is irritant so better combined with steroid to get a greater response, fewer S.E., plus steroid sparing

Topical corticosteroids

Most commonly used, clean & effective
but frequent S.E.; such as:
1- dermal atrophy
2-tachyphylaxis
3-early relapse
4- precipitation of pustular type

• Indications of topical steroids:

1)On face, ears & flexures2) Patients can’t tolerate tar, dithranol, etc, due to allergic or irritant reaction3)Unresponsive psoriasis of scalp, palm & sole4) Patients with minor, localized type5) In combination with other modalities

Physical treatment 1- Light therapy

Most patients benefit from sunlight
UVR is the main treatment for moderate to severe psoriasis
S.E. include sunburn & increased risk of skin CA
Artificial UVB by fluorescent bulbs, either narrow band(311nm.) or broad band
Max. effect achieved is at MED (min. dose to induce erythema in a test patch after 24h)

2-PUVA

Psoralens are natural phtosensitizers
High intensity, long wave UVR( UVA), given 2 hours after ingestion of 8-methoxy psoralen, twice weekly
20-25 sessions are needed, +maintenance doses
Clearance ‘ll occur in 75% of patients
Not for young patients
UVR resistant glasses worn for24 hours

Systemic treatment 1- Methotrexate

• Folic acid antagonist, inhibit DNA synthesis in S phase
• Given orally or parentally , 7.5-15mg, once weekly
• Minor S.E. nausea & malaise in 1st.24hr.
• Serious S.E. are liver toxicity, marrow suppression, teratogenicity & male oligospermia
• Should monitor liver, renal & marrow function, before & during treatment

2-Neotigasone (=Acitretin)

Acitretin is vitamin A analougue
Especially effective in pustular psoriasis of palms& soles, & plaque psoriasis
Frequent minor S.E. as dryness of skin & m.m., pruritis, hair fall, & paronychia.
Serious S.E. are hyperlipidemia especially of triglycerides & teratogenicity
Can be combined with PUVA= RE-PUVA

3-Cyclosporine

Inhibits cell mediated immunity
Very effective in psoriasis
Serious S.E. as hypertension, renal damage, persistent viral warts & a risk of skin cancer.

4- Biologics

Biologics: new, monoclonal antibodies to key pathological pathways in psoriasis
Against T.N.F. α(alpha)
Against receptors involved in T-cell trafficking as interleukin 12/23(IL-12/IL-23) blockade agents
Interleukin 17-A
Expensive, requires careful consideration of medical Hx, disease severity & monitoring of infections