Summary
Psoriasis affects 1 to 5 p. 100 of the population depending on the regions of the world, but it is difficult to estimate the percentage precisely because many patients do not treat their symptoms, either because they consider that the treatments cause more discomfort than the disease itself, or through discouragement.
Uncomplicated psoriasis plaques are red, typically covered with micaceous scales. Removal of the scales with a curette leads to redness and bleeding. The scales which are always present may differ considerably in appearance. They may be ostreaceous, forming a helmet on the scalp, for example, or scurfy, closely resembling those observed in patients with seborrhoeic dermatitis.
1 - HISTOLOGY
Psoriasis is characterised histologically by acanthosis and papillomatosis, indicative of excessively rapid renewal of the epidermis, associated with a differentiation disorder leading to continuous or discontinuous parakeratosis.
These abnormalities are associated with inflammatory cell infiltration at a very early stage of plaque development. The cell infiltrate originally consists of polynuclear neutrophils, which often accumulate to form micro-abscesses under the horny layer of the epidermis leading to major alterations of the membranes of the keratinocytes in the vicinity due to the release of lysosomal enzymes. These alterations permanently activate epidermal renewal. The other cells making up the infiltrate of the skin lesions consist of T lymphocyte subpopulations, particularly CD4 cell in the dermis and CD8 cells in the epidermis. The T lymphocytes play a major role in the pathophysiology of psoriasis although it is not known which roles the CD4 and CD8 cells play respectively, or how they participate in the maintenance of local inflammation and hyperproliferation.
Histologically, the lesions may be atypical in some areas of the body, particularly the palms of the hands or soles of the feet where spongiosis is often observed. Therefore, it is pointless to perform a skin biopsy to differentiate between psoriasis and eczema on the palms of the hands or soles of the feet.
2 - LINKS
EADV leaflets published in 2019, produced by the EADV Psoriasis Task Force:
- Psoriasis a closer look - What, how, where
- Chronic disease, chronic frustations
World directory of Psoriasis Medical Resources for patients
2.1 - INTERNATIONAL
International Federation of Psoriasis Associations / IFPA
2.2 - NATIONAL PATIENTS ASSOCIATIONS
ARGENTINA
AUSTRALIA
AUSTRIA
BELGIUM
BULGARIA
CANADA
CHILE
Corporación de Psoriasis de Chile
CHINESE TAIPEI
COLOMBIA
Fundación Colombiana de Psoriasis
Fundacion de Apoyo al Paciente con Psoriasis (FUNDAPSO)
CZECH REPUBLIC
Psoriatic and Atopic Eczema Association Czech Republic (SPAE CZ)
DENMARK
EL SALVADOR
Psonuves, Psoriasis Nueva Vida El Salvador
ESTONIA
EPsoL- Estonian Psoriasis Association
FINLAND
GERMANY
Psoriasis Selbsthilfe Arbeitsgemeinschaft e.V. (PSOAG)
Deutscher Psoriasis Bund e. V.
HONG KONG
Hong Kong Psoriasis Patients Association
HRVATSKA/CROATIA
Croatian Psoriasis Association
HUNGARY
Psoriasis Club of Szeged (Szegedi Pszoriázis Klub)
ICELAND
Samtök Psoriasis og Exemsjúklinga (SPOEX)
INDONESIA
Indonesian Psoriasis Care Foundation
IRELAND
ISRAEL
ITALY
JAPAN
KENYA
REPUBLIC OF KOREA
MALAYSIA
Psoriasis Association of Malaysia
MALTA
MEXICO
Asociación Mexicana contra la Psoriasis
NETHERLAND
Psoriasis Vereniging Nederland
NORWAY
The Psoriasis and Eczema Association of Norway (PEF)
The Psoriasis- and Eczema Youth Association of Norway (PEF-ung)
PANAMA
PHILIPPINES
Psoriasis Philippines (PsorPhil)
POLAND
PORTUGAL
PSOPortugal - Associacao Portuguesa da Psoríase
PUERTO RICO
Asociación Puertorriqueña de Ayuda al Paciente de Psoriasis, APAPP
ROMANIA
SPERANTA - Asociatia Pacientilor cu Psoariazis din Romania
RUSSIA
Interaction - Regional Public Organization of the Help to People Having Psoriasis
The Interregional Charitable Non Governmental Organization
"Society of Patients with Psoriasis"
SCOTLAND
SINGAPORE
Psoriasis Association of Singapore
SLOVAKIA
Slovak Psoriatics and Atopics Association
SLOVENIA
SOUTH AFRICA
South African Psoriasis Association
SPAIN
SWEDEN
SWITZERLAND
Schweizerische Psoriasis und Vitiligo Gesellschaft
TURKEY
Türkiye Sedef Hastalan Dayanisma Dernegi
UKRAINE
Ukrainan Psoriasis Association
UNITED KINGDOM
www.psoriasis-association.org.uk
www.britishskinfoundation.org.uk/psoriasis
www.papaa.org (psoriasis and psoriatic arthritis alliance)
UNITED STATES
National Psoriasis Foundation/USA
VIETNAM
PsorViet, Vietnam Psoriasis Network
×
N.B. : This limited content is for the general public. If you are a health professional, click here to register for free and gain access to a dedicated deeper content.
If you already have an account, log in!
Therapeutics in Dermatology, Fondation René Touraine © 2001-2013
