Psoriasis plaque

Specialty: Skin.

• typical psoriatic plaque
• psoriatic erythematosquamous lesion

Why it occurs

• Chronic inflammatory disorder of genetic and immune-mediated basis characterized by the activation of the IL-23/IL-17/TNF-alpha cytokine axis that stimulates the disordered proliferation of keratinocytes
• Acute psychological stress as a trigger for psoriasis vulgaris outbreaks
• Previous or active infections (streptococcal in eruptive forms, human immunodeficiency virus)
• Mechanical trauma located in the skin (positive Koebner phenomenon)
• Alcohol consumption, active smoking or triggering drugs (beta blockers, lithium, antimalarials).

Initial workup

Systematic clinical inspection (well-defined plaques with an erythematous base covered by pearly scale on the elbows, knees and scalp). Brocq's methodical scraping to confirm Auspitz bleeding dew. Punch skin biopsy reserved for doubtful cases of psoriasis with atypical presentation (erythrodermic, pustular or reverse).

Standard management

• Clobetasol propionate 0.05% or mometasone furoate 0.1% ointment — topical corticosteroids for localized inflammatory management; applied 1-2 times a day
• Calcipotriol 0.005% in ointment — vitamin D analogue for the maintenance and control of cell proliferation
• Methotrexate — systemic treatment of choice in extensive involvement of more than 10% of the body surface, dose of 15 mg/week orally
• Adalimumab or Ustekinumab (highly effective biological therapies directed against TNF-alpha or IL-12/23 respectively, indicated in severe forms refractory to conventional therapy).