Symptoms and treatment of Psoriasis

Definition
Chronic skin disease, benign, characterized by an erythematous, scaly rash, which evolves in spurts, predominantly on the elbows, knees, scalp.
Psoriasis is characterized by an abnormal proliferation and differentiation of keratinocytes associated with infiltration of the dermis and epidermis by T cells and neutrophils forming microabscesses in the stratum corneum.

Prevalence
Psoriasis is a chronic skin disease which affects around 2% of the population.

Etiology
The etiopathogenesis is still unknown:
- Existence of hereditary factors in particular admitted with an attack family (inconstant connection to certain HLA groups),
- Role of psychological trauma (hormonal changes, stress ..) and infections in the determination of relapses (streptococcal infections),
- Some research suggests that psoriasis results from immune abnormalities.

Symptoms and signs
Psoriasis manifests itself in several ways, most often by the appearance of red or pink skin patches covered with dry scales and whitish more or less thick material that detach discovering a red skin and saignottante.
The plates, especially those present on the scalp, crumble and lamellae white, similar to dandruff, become detached from the epidermis.
Psoriasis is sometimes accompanied by itching and fissures (particularly on the hands and feet).
Particularly serious forms exist:
- Because of the localization: face, folds, genitals, scalp, with palmoplantar or nail,
- Pustular in character: it is localized amicrobiennes pustules on the hands and feet and diffuse or generalized,
- By their extension: generalized forms bearing the clinical features of psoriasis (psoriasis universalis) or taking on the appearance of erythroderma,
- Because of inflammatory joint diseases: psoriatic arthritis, psoriatic spondylitis, inflammatory joint flare accompanying forms generalis

Location

Psoriasis affects certain specific areas of the body:
- The most frequently: The scalp, elbows, knees, back
- The less frequently: the groin, armpits, the palms, soles, nails (which have multiple punctate depressions giving a corner "in thimble"), buttocks, around the navel The inside of the cheeks, the external genitalia.

Diagnosis
The diagnostic elements:
- Location at the extensor surface of the members
- Raised red, scaly plates
- The scales removed with a curette, which gives a whitish spot "in the task of candle"
- Itching is variable and inconstant

In most cases, the diagnosis does not pose a problem. However, some atypical forms and certain locations are more difficult to diagnose:
- Folds psoriasis (inverse psoriasis) that realizes an aspect of chronic intertrigo resistant to usual treatment,
- Nail psoriasis may be mistaken for onychomycosis (in half the cases the two are related),
- Psoriasis of the scalp and face that is very similar to seborrheic dermatitis,
- Guttate psoriasis, eruptive child and adolescent who may be mistaken for a viral rash or pityriasis rosea.
In these particular forms, the biopsy provides only rarely a definitive diagnosis. This is essentially the presence of typical lesions remote, and especially the evolution of chronic lesions that are useful for diagnosis.

Evolution
The age of onset is highly variable, the evolution is undefined, unpredictable, made outbreaks and remissions of varying length and more or less complete (persistence of lesions of the elbows and knees) in which the lesions disappear without scars, hyperpigmentation at best or a stain amelanotic transient.
Some medications worsen psoriasis (blockers, inhibitors of angiotensin converting enzyme - ACE inhibitors, lithium).

Treatments
In the current state of knowledge, there is no treatment that can cure psoriasis and all treatments can only claim a suspensive action. The hopes of radical treatment are related to the discovery of genes responsible for disease.
First look for triggers: infections, drugs.
The treatment of psoriasis limited to a few spots, called first-line derivatives of vitamin D that can be associated with local corticosteroid.
There are also topical retinoid (Tazarotene)
In the most extensive psoriasis, phototherapy is the treatment of choice, whether ultraviolet B (usually narrow spectrum - 311 nm) or PUVA introduces these ultraviolet A decision of psoralen (Méladinine most often).
Finally in severe (generalized psoriasis, erythrodermic or pustular) should be called to Methotrexate, retinoids (Soriatane) or cyclosporin.
These therapies are not without major side effects and require a complete pre-therapeutic and regular monitoring in specialized settings.