psoriaasis

Psoriasis, often misspelled as psoriaasis, is a chronic inflammatory skin condition driven by immune dysregulation. It causes red, thickened plaques with silvery scales, most commonly on the elbows, knees, scalp, and lower back. The disease is non-contagious and affects about 2-3% of people worldwide. Onset most often occurs in late adolescence or early adulthood but can arise at any age.

The main form is plaque psoriasis, but several other variants exist, including guttate, inverse, pustular, and erythrodermic psoriasis. Triggers include infections, skin injury (Koebner phenomenon), physical or emotional stress, smoking, obesity, and certain medications. Genetic factors contribute to susceptibility, and comorbid conditions such as psoriatic arthritis are commonly associated.

Diagnosis is usually clinical, based on characteristic skin findings. A skin biopsy may be used to distinguish psoriasis from other skin disorders when the diagnosis is uncertain.

Management aims to control symptoms, prevent progression, and improve quality of life. Treatments are tailored to disease severity and affected areas. For mild disease, topical therapies such as corticosteroids and vitamin D analogs (eg, calcipotriol) are first line. Phototherapy with ultraviolet B is effective for broader involvement. For moderate-to-severe psoriasis, systemic treatments may be used, including methotrexate, cyclosporine, or retinoids. Biologic therapies targeting immune pathways (for example TNF inhibitors, IL-17 inhibitors, IL-23 inhibitors, and IL-12/23 inhibitors) are options for more extensive disease or psoriatic arthritis.

Psoriasis can impact mood and daily functioning and is associated with higher risks of psoriatic arthritis, cardiovascular disease, and metabolic syndrome. With appropriate treatment and lifestyle measures, many people achieve good control of symptoms.