Psoriasis
Chronic inflammatory skin condition — plaques, triggers and management
Psoriasis is a chronic immune-mediated skin condition that affects around 2% of the UK population. It causes skin cells to build up rapidly on the surface of the skin, forming scales and red or silvery plaques that can be itchy and sometimes painful. While there is no cure, many effective treatments are available to help control symptoms.
What is Psoriasis?
Psoriasis occurs when the immune system mistakenly attacks healthy skin cells, speeding up the skin cell production cycle dramatically. Normal skin cells are replaced every 28–30 days; in psoriasis, this happens in just 3–5 days. The result is a build-up of cells on the skin surface, forming the characteristic plaques. Psoriasis is not contagious. It follows a relapsing and remitting course, with periods of flare alternating with periods of relative remission. The condition can have a significant impact on quality of life, including emotional wellbeing and mental health.
Types of Psoriasis
There are several forms of psoriasis: Plaque psoriasis is the most common, affecting about 80–90% of people with the condition — it presents as raised, red patches covered with a silvery-white scale, most commonly on the elbows, knees, scalp and lower back. Guttate psoriasis presents as small, teardrop-shaped lesions, often triggered by a streptococcal throat infection, and is more common in younger people. Scalp psoriasis affects the hairline and behind the ears. Nail psoriasis causes pitting, discolouration and thickening of the nails. Palmoplantar psoriasis affects the palms and soles. Pustular and erythrodermic psoriasis are less common but more severe forms.
Causes & Triggers
Psoriasis has a strong genetic component — having a first-degree relative with psoriasis significantly increases your risk. The immune system plays a central role, with T-cells mistakenly activated against skin cells. Common triggers that can provoke or worsen psoriasis include: streptococcal throat infections (especially guttate psoriasis), stress, skin injury (the Koebner phenomenon), smoking, excessive alcohol consumption, and certain medications including lithium, beta-blockers, NSAIDs and antimalarials. Obesity is also associated with more severe psoriasis.
Assessment & Impact
The impact of psoriasis is measured using standardised scoring tools. The PASI (Psoriasis Area and Severity Index) assesses the extent and severity of skin involvement, while the DLQI (Dermatology Life Quality Index) captures the impact on daily life and emotional wellbeing. A thorough evaluation of psoriasis severity is essential to guide treatment decisions — mild psoriasis affecting small areas may be well-managed with topical treatments, while moderate-to-severe disease affecting quality of life may benefit from phototherapy or systemic therapy. Psoriasis is also associated with psoriatic arthritis in up to 30% of patients, which causes joint pain and stiffness.