• It is a Dermatose erythematoussquameuse devolution chronic and recurrent.
  • touching 1 at 2% of the general population.
  • It can occur at all the ages (20 and 30 years +++) but remains rare before dix years (10 at 15%)
  • The psoriasis touch the man and the women at equal frequencies.
  • Diagnostic essentially clinique
  • Dermatose benign, The form usual poses one prejudice aesthetic, but significantly affects the quality of life, however there of the forms graves departure:
  • The scope of the injury.
  • The modification from lesion elementary.
  • The association at of the arthropathies. (erythroderma, psoriasis pustular, rheumatism psoriasique)
  • TRT East symptomatic : repose often sure of the therapeutic locales, the treatments general are reserved to the forms severe

Pathogénie rest times elucidated :

– Psoriasis is characterized by epidermal renewal acceleration

* Turn normal epidermal is over 30 days

* only in psoriasis 7 days

– This is associated with immune disorders

– activation des LT -> secretion of various cytokines (TNF Alpha, IL12, IL23 ... )

* causing psoriatic inflammatory reaction

* responsible for increased keratinocyte proliferation

This is a 'multifactorial' disease – genetic factors

* 30 % of psoriatic are family

* Psoriasis in children is often linked to the histocompatibility antigens (HLA-Cw6) – environmental factors

* alcohol and tobacco : resistance factors TRT

* infections : especially in outbreaks of psoriasis in children

* psychological factors and drugs (lithium salt, beta-blockers, IEC, CTC … ) may induce or aggravate psoriasis


Lesion elementary : plaque erythematoussquameuse rounded and flopn limited. – scaly surface layer

A- Dander surface :

* Color : whitish and dull, sometimes micaceous * Surface : smooth or rough

* these scales are dry, size and of varying thickness

* may mask completely or partially erythema

  • curettage methodical from Brocq ;

Sfire from whitening

Sign from the task from candle

Sign of the peelable film.

Arrachement da film adherente at plan deep

Sign from the dew bloody or sign of Auspitz :

Apparaition from fines gouttlettes hemorrhagic (setting at not of the buds dermal)

B- erythema East underunderlying :

– underneath the squamous layer

Color dew feature, rouge cogestif (earlier es infs)

Disappears at the pressure-vitro. – Surface smooth and dry

not from pain, not infiltration, not from pruritus.

C- Group and topography :

Name :

– Variable,

– rarely isolated psoriasis plaque,

– often multiple or diffuse

Ofmension :

point «Punctata» I in drops "Guttata" of a few mm

Nummulaire (nummulus = coin) a few cm in diameter

In plaque : more or less geometric contours or vine occupying large areas

Universalis : generalized that almost touches the entire integument

topographyAPHY :

– very evocative of diagnosis

At beginning and pendant all the duration from the sickness ; zones from friction :

elbows, knees, edges cubitaux of the forearm, tibial regions, sacral, palms and soles, scalp (refuge area or bastion).

  • Zones from friction of the clothing or manipulation regular a equipment (Koebner phenomenon).

signs functional (pruritus) : the psoriasis East little or not prurigineux


A- According seat :

1- shapes Clasicos : bastion :

2- Psoriasis of the more : Psoriasis inverted.

– red plate glossy and smooth little or no scaly

– seat : interfessier ornaments - inguinaux – genital areas – in breast – axilla

– areas macerated, wet ; erythema micaceous.

Of them diagnostic differential : eczema and mycosis.

3- Psoriasis of please haired :

– erythematous scaly plaque ciconscrites much limited varying sizes covered large dry scales through which the hair (non alopéciant) – real shell covering the entire scalp

  • The thickness of please haired and the presence of the hair mask erythema.
  • Often ; helmet squameux.
  • Of them diagnostics differential : moth of please haired and false moth infectious.

4- Psoriasis of the nails : 3050 % of the case

– sometimes isolated,

– Appearance of depression interspersed cupiliformes (nail thimble)

– onycholysis with distal abruption

– hyperkeratosis subungual

– leuconychie

  • Not from spots erythematoussquameuses.
  • streaks transverse whitish.
  • Pachyonychie : thickening from the nail.
  • Diagnostic differential : onychomycoses.

5- Psoriasis of the palms and of the plants :

– often bilateral -> keratodermia in islands or diffuse

Of them diagnostics differential :

  • Durillons and verrues plantar.
  • hearts at pied.

6- psoriasis of face :

Rare, the can to take l’aspect d'a dermatitis seborrheic (sebopsoriasis)

7- psoriasis of the mucous :

– On the tongue :

* geographic tongue especially in pustular psoriasis

* langue scrotale

– On the glans : well limited spots, purely erythematous

B- By age :

– may be early : Psoriasis nappies (napkin psoriasis)

– in children : often sharp drops and can follow a nasopharyngeal infection The face is usually achieved in adults

C- Psoriasis caused :

– pharmaceuticals : they can induce or worsen psoriasis or be responsible for resistance to TRT ( lithium salts, beta-blockers, IFN alpha ) – Koebner phenomenon : characterized by the appearance of psoriatic lesions on a skin trauma : scraping ridges, surgical scars ...

D- severe :

1- Psoriasis pustular :

  • Lesion elementary : pustule blancyellowish asked sure a base erythema diffuse which dries quickly and exfoliates.
  • Fever 40°C and alteration from the state general.
  • This psoriasis simulate a sickness infectious and son prognosis spontaneous East grave which can lead to death of the patient.
  • The psoriasis pustular can to be limit to the mains and to the feet and simulate a eczema : is acromegaly.
  • The psoriasis pustular East often the complication a psoriasis vulgar treaty through corticosteroids.

2- Psoriasis erythrodermic :

  • Erythema diffuse edematous infiltrated with skin and cardboard and accented wrinkles.
  • the elderly Button.
  • Fluid and electrolyte loss due to edema ; life-threatening game.
  • Superinfection and thermoregulation disorders
  • Complication corticosteroids

3- Psoriasis arthropathique :

  • 25% of the psoriasis develop a arthropathie.
  • Mono or trace arthritis, arthritis seronegative, SPA.


  • Sickness chronic evolving through outbreaks.
  • Prognosis functional and vital born are what in Game.
  • repercussion sociopsychological.
  • Existence from pharmaceuticals inducers from outbreaks or from forms graves of psoriasis : AINS, APS, beta-blockers, lithium salts, corticosteroids.
  • Environment :
  • the vacation, been and the soleil ; improvement.
  • Winter ; aggravation.


A- Diagnostic positive :

1- Clinique : +++

2- histology in case from doubt diagnostic :

a)- ISepidermis :

  • hyperkeratosis parakératosique.
  • Hyperacanthose.
  • Microabscess amicrobiens.

b)- Dermis :

  • thickening and dilatation of the buds dermal.
  • vessels turgescents.
  • Infiltration from cell mononuclées.

c)- Hypoderme and annexes : Absence from modifications

B- Diagnostic differential :

  1. Eczema microbial.
  2. epidermismycoses.
  3. Lichen plan : Dermatose papulosquameuse very CASTROTHEODORICIENNE up also the mucous.
  4. Hématodermie (lymphoma associate).


A- Psoriasis limit :

1- keratolytic :

  • Vaseline salicylate 0,5 at 10%.
  • Intoxication ; dyspnea, stop lavage from the skin.

2- Gearboxes :

  • Tar from coal.
  • Oil from cade.
  • Dermocorticoïdes.
  • derivatives vitamin D : Calcipotriol, Daïvonex.

B- Psoriasis expanded :

  • PUVA ; adults.
  • PUVB with tar ; children.

C- Psoriasis grave : extended or refractory :

  • derivatives from the vitamins A acid ; retinoid, Soriatane.
  • Association retinoid with PUVA.
  • If not antimitotic : methotrexate in injectable.

D- Psoriasis arthropathique :

  • The AINS and corticosteroids against-indicated.
  • Means physique if not retinoid or methotrexate.
  • cyclosporin.