Psoriasis

psoriasis Zhang Jiang-an Dept. of Dermatology The first affiliated hospital of zhengzhou university

Definition  Psoriasis is a common, genetically

determined, inflammatory and proliferative disease of the skin, the most characteristic lesions consisting of chronic, sharply demarcated, dull-red, scaly plaques, particularly on the extensor prominences and in the scalp.  This disease is enormously variable in duration and extent and morphological variants are common.

Epidemiology(1)  Psoriasis affects 2% population in

Europe and North America.  The low prevalence of psoriasis in oriental people is now well-recognized. In Singapore, it is commoner in Indians than in Chinese or Malays.  The sex incidence is equal.

Epidemiology(2)  The condition may start at any age, even

in the elderly, but the peak onset is in the 2nd and 3rd decades. It is unusual in children less than 8 years old.  Females tend to develop psoriasis earlier than males.  Patients with a family history of psoriasis tend to have an earlier age of onset.

Etiology and pathogenesis(1)  Genetic predisposition  The evidence that psoriasis may be

inherited is beyond doubt.  About 35% of patients show a family history;  Identical twin studies show a concordance of 80%;  There are strong correlations with the HLA antigens CW6, B13, B17.

Etiology and pathogenesis(2)  Provocation and exacerbation  Several factors are now accepted as of

importance in provoking a new episode of psoriasis or in exacerbating preexisting disease.  ①trauma A wide range of injurious local stimuli, including physical, chemical, electrical, surgical, infective and inflammatory insults has been recognized to elicit psoriatic lesions.

Etiology and pathogenesis(3)  ②infection The role of streptococcal

infection, especially in the throat, in provoking acute guttate psoriasis has long been recognized.  ③endocrine factors Many researchers have found that there are peaks of psoriasis incidence at puberty and at the menopause.

Etiology and pathogenesis(4)  ④sunlight Although sunlight is generally

beneficial, a small minority of psoriatics are provoked by strong sunlight and suffer summer exacerbations in exposed skin.  ⑤metabolic factros Hypocalcaemia (e.g. following accidental parathyroidectomy) and dialysis have precipitated psoriasis.

Etiology and pathogenesis(5)

 ⑥drugs Some drugs can induce or

exacerbate psoriasis. The most frequent associations include the administration of lithium, β-adrenergic blocking agents and antimalarials, and the withdrawal of systemically administered corticosteroids.  ⑦psychogenic factors There is evidence that the severity of psoriasis may depend on prior stress, although one controlled questionnaire study did not support this view.

Etiology and pathogenesis(6)  ⑧alcohol and smoking A Finnish study

confirmed that alcohol is a risk factor for psoriasis in young and middle-aged men. The association between smoking and psoriasis has been reviewed; reports suggest an increased risk for both palmoplantar pustulosis and chronic plaque psoriasis.

Clinnical presentation(1)  Psoriasis varies in severity from the

trivial to the life-threatening.  Generally, according to the clinical features, psoriasis is divided into four types: psoriasis vulgaris, pustular psoriasis, psoriatic arthropathy and erythrodermic psoriasis.

Clinnical presentation(2)  psoriasis vulgaris--plaque psoriasis(1)  Plaque psoriasis is the typical

presentation of psoriasis vulgris.  The lesions often involve the elbows, knees, scalp hair margin, sacrum.  The plaques vary in diameter from one to several centimetres and are oval or irregular in shape.

Clinnical presentation(3)  psoriasis vulgaris--plaque psoriasis(2)  There may be any number of lesions or only a

single one, and, when multiple, may be symmetrically distributed.  The red plaques are often surmounted by the very characteristic silvery white scaling. The removal of psoriatic scales usually reveals an underlying smooth, glossy, red membrane with small bleeding points where the thin suprapapillary epithelium is torn off (Auspitz sign).

Clinnical presentation(4) plaque psoriasis(3)

After the removal of scales, smooth, glossy, red membrane

②

①

③ Red plaques covered by silvery white scaling

The small bleeding point

Clinnical presentation(5)  psoriasis vulgaris--guttate

psoriasis(1)  Guttate psoriasis is an acute symmetrical eruption of “drop-like ” lesions usually on the trunk and limbs.  The form mostly occurs in adolescents or adults and may follow a streptococcal throat infection.

Clinnical presentation(6)

Small red drop-like lesions on the trunk and limbs

Clinnical presentation(7) Köbner phenomenon(1)  Köbner phenomenon is that various types of

trauma may elicit the disease in previously uninvolved skin.  The reported incidence has varied between 38 and 76% of patients with psoriasis. The Köbner reaction is often thought to be more frequent in actively spreading severe psoriasis.  The Köbner phenomenon usually occurs 7-14 days after injury.

Clinnical presentation(8) Köbner phenomenon(2)

After tattoo, the Köbner phenomenon is presented.

Clinnical presentation(9)  Modification by

site--scalp  Often, very thick plaques develop, especially at the occiput, with the fascicle-like hair.

Clinnical presentation(10)  Modification by site—nail involvement  This is seen in association with all types of

psoriasis of the skin, and is frequently present with psoriatic arthropathy.  Although pitting is the most frequent change seen, discoloration, subungual hyperkeratosis and onycholysis are common, and splinter haemorrhages occur.

Clinnical presentation(11) Fingernail pitting in psoriasis Subungual hyperkeratosis in psoriasis

Clinnical presentation(12) Erythrodermic psoriasis(1) Two forms exist.  The first form can be regarded as extensive plaque psoriasis involving all, or almost all, the cutaneous surface. There are usually some areas of uninvolved skin. The psoriatic characteristics are retained, mild treatment is well tolerated, and the prognosis is good.

Clinnical presentation(13) Erythrodermic psoriasis(2)

 Extensive chronic

plaque psoriasis with coalescence of lesions and the potential to evolve into an erythrodermic form.

Clinnical presentation(14) Erythrodermic psoriasis(3) The second form is part of the spectrum of 'unstable' psoriasis. It can be precipitated by infections, hypocalcaemia, antimalarials, tar and withdrawal of corticosteroids. It is more frequent in arthropathic psoriasis. Generalized pustular psoriasis may revert to an erythrodermic state.

Clinnical presentation(15) Erythrodermic psoriasis(4) The characteristics of the disease are often lost, the whole skin is involved, the patient may be febrile and ill, the course is often tumultuous or prolonged, relapses are frequent, and there is an appreciable mortality. In contrast to the stable form, itching is often severe.

Clinnical presentation(16) Erythrodermic psoriasis(5)

 Acute, unstable,

erythrodermic psoriasis.

Clinnical presentation(17) Psoriatic arthropathy (1)  Psoriatic arthritis is a chronic inflammatory

arthritis that is commonly associated with psoriasis.  Approximately 5% of patients with psoriasis develop psoriatic arthritis.  the exact etiology is unknown and is probably multifactorial, including immune-mediated, genetic, and environmental causes. Environmental factors may include trauma, infection, and stress.

Clinnical presentation(18) Psoriatic arthropathy (2)  Psoriatic arthritis usually develops in the fourth to sixth decades of life, but it can occur at almost any age.  Psoriasis appears to precede the onset of psoriatic arthritis in 60-80% of patients. Occasionally, arthritis and psoriasis appear simultaneously. In addition, cutaneous eruptions may be preceded by the arthropathy.

Clinnical presentation(19) Psoriatic arthropathy (3)  Nail pitting, Beau lines, leukonychia, onycholysis, oil spots, subungual hyperkeratosis, splinter hemorrhages, spotted lunulae, and cracking of the free edge of the nail all support the diagnosis of psoriatic arthritis, especially of the distal interphalangeal (DIP) joint type.

Clinnical presentation(20) Psoriatic arthropathy (4)  Scaly, erythematous plaques; guttate lesions; lakes of pus; and erythroderma are all types of psoriatic skin lesions that may be seen in the context of psoriatic arthritis.  Joint findings may include dactylitis (sausage digits), enthesopathy (reflecting inflammation of the insertion points of tendon into bone), tendonitis, and spondylitis.

Clinnical presentation(21) Psoriatic arthropathy (5)  Psoriatic arthritis is a chronic inflammatory condition for which no specific laboratory tests are available.  The main differential diagnosis is RA, which is negative in psoriatic arthritis, but positive (85% of patients) in rheumatoid arthritis.

Clinnical presentation(22) Psoriatic arthropathy (5)  Psoriatic arthritis,

showing peripheral oligoarthropathy with sausage-like digital swelling.

Clinnical presentation(23) Pustular psoriasis (1)  Pustular psoriasis is an uncommon form of psoriasis consisting of pustules on an erythematous background.  Cutaneous lesions characteristic of psoriasis vulgaris may be present before, during, or after an acute pustular episode.

Clinnical presentation(24) Pustular psoriasis (2)  The following have reportedly triggered an        

eruption: ①Withdrawal of systemic steroids ② Drugs, including salicylates, iodine, et al ③ Strong, irritating topicals, including tar, anthralin, et al ④ Infections ⑤ Sunlight or phototherapy ⑥ Cholestatic jaundice ⑦ Hypocalcemia ⑧Idiopathic in many patients

Clinnical presentation(25) Pustular psoriasis (3)  Generally, pustular psoriasis may be classified into two types depending on the clinical course, localized pustular psoriasis (including palmoplantar pustulosis and acrodermatitis continua) and generalized pustular psoriasis.

Clinnical presentation(26) Pustular psoriasis (4)  Palmoplantar pustulosis(1)  Palmoplantar pustulosis is a common condition in which erythematous and scaly plaques studded with sterile pustules persist on the palms or soles. The disease is chronic and very resistant to treatment.

Clinnical presentation(27) Pustular psoriasis (5)  Palmoplantar

pustulosis(2)  Within the red plaque, numerous pustules are present, usually 2-5mm in diameter.

Clinnical presentation(28) Pustular psoriasis (6)  Acrodermatitis continua (1)  A chronic, sterile, pustular eruption affecting initially the tips of fingers or toes which tends slowly to extend locally but which, in adults, may evolve into generalized pustular psoriasis. Onset is often related by the patient to minor trauma, or infection at the tip of the digit.

Clinnical presentation(29) Pustular psoriasis (7)  Acrodermatitis

continua (2)  Acrodermatitis continua with destruction of nail plate and numerous pustules on the erythematous backgroud.

Clinnical presentation(30) Pustular psoriasis (8)  Generalized pustular psoriasis(1)  Generalized pustular psoriasis is a rare but serious and even life-threatening form of psoriasis.  Sheets of small, sterile yellowish pustules develop on an erythematous backgroud and may rapidly spread.  The onset is often acute.  The patient is unwell, with fever and malaise.

Clinnical presentation(31) Pustular psoriasis (9)  Generalized

pustular psoriasis(2)  Sheets of small, sterile yellowish pustules develop on an erythematous backgroud.

Diagnosis and differential diagnosis(1)  The characteristics already defined are

usually sufficient to enable the diagnosis to be made, but doubt may arise in atypical cases, and in particular sites, and when psoriasis is complicated by or alternates with other diseases. Therefore, psoriasis should be differentiated from some diseases.

Diagnosis and differential diagnosis(2)  Psoriasis vulgaris should be

differentiated from the following:  Seborrheic dermatitis, eczema, lichen planus, pityriasis lichenoides chronica, candidiasis, tinea cruris, pityriasis rubra pilaris, secondary syphilis, et al.

Diagnosis and differential diagnosis(3)  Erythrodermic psoriasis should be

differentiated from the erythroderma from other reasons, such as eczema, lymphoma, drug eruption, bullous ichthyosiform erythroderma, et al.

Diagnosis and differential diagnosis(4)  Psoriatic arthritis should be

differentiated from the following:  rheumatoid arthritis, ankylosing spondylitis, reiter's disease.

Diagnosis and differential diagnosis(5)  Localized pustular psoriasis should be

differentiated from the following:  Tinea, eczema, chronic allergic contact dermatitis, et al.  Generalized pustular psoriasis should be differentiated from the following:  Subcorneal pustular dermatosis, herpes gestation, acute generalized eruptive pustulosis, et al.

Treatment(1)  General advice (therapy)  Topical therapy  UV phototherapy  Systemic therapy

Treatment(2) General advice (therapy)  Rest, mild sedation, removal from a troublesome environment, a holiday or a short stay in hospital may all help to turn the therapeutic tide.  Harmless placebos may give comfort and should not be despised.  Diet is unimportant. Diets rich in zinc and low in tryptophan, protein do not influence the disease.

Treatment(3) Topical therapy  Topical medicaments include  Tar  Dithranol (anthralin)  Topical corticosteroids  Intralesional corticosteroid therapy  Vitamin D analogues  Topical or intralesional cytostatic therapy  Occlusive dressings alone

Treatment(4) UV phototherapy  UV phototherapy include:  UVB  PUVA

Treatment(5) Systemic therapy  Methotrexate  Hydroxyurea  Retinoids (Etretinate, Isotretinoin,

Acitretin)  Cyclosporin A  Systemic corticosteroids  6-Thioguanine

Treatment(6)  Most stable discoid psoriasis should first

be approached with outpatient topical therapy, which disrupts the patient's routine as little as possible.  Tar preparations and vitamin D analogues are appropriate, but corticosteroids can be used for localized psoriasis. If necessary, dithranol can be introduced later but is more difficult to handle.

Treatment(7)  If sunlight or UVB phototherapy are

available, light can be added at this stage or earlier.  If the psoriasis is severe and extensive and the above initial measures have failed, more intensive tar or dithranol therapy should be considered, in a daycare unit or a hospital if such facilities exist, with or without UV phototherapy.

Treatment(8)  The indications for intralesional

corticosteroid injections, PUVA therapy, retinoids, cytotoxic drugs and cyclosporin should be restricted to those patients whose psoriasis is physically, socially, economically or emotionally disabling, and in whom conventional and conscientious topical therapy has failed.

key points  Definition of psoriasis  Four types of psoriasis  Clinical presentation of psoriasis vulgaris  Köbner phenomenon