Psoriasis Explained: Causes, Types and Treatment

What psoriasis actually is

Normally, skin cells are made deep in the skin and slowly rise to the surface over about a month, where they are shed unnoticed. In psoriasis, the immune system becomes overactive and speeds this process up dramatically, so new cells reach the surface in a few days. They pile up before the old ones can fall away, forming the raised, scaly patches known as plaques. This is why psoriasis is described as an immune-mediated condition, not simply a skin complaint. Understanding this helps explain two things: why it tends to come and go in flares rather than being constant, and why some treatments work by calming the immune system rather than just moisturising the skin.

The main types

Psoriasis comes in several forms. The most common by far is plaque psoriasis, causing well-defined patches often on the elbows, knees, lower back and scalp. Guttate psoriasis appears as many small, drop-shaped spots, frequently in children or young adults after a throat infection. Inverse psoriasis affects skin folds such as the groin or under the breasts, looking smooth and shiny rather than scaly. Pustular and erythrodermic psoriasis are rarer and more serious forms that need urgent medical attention. Psoriasis can also affect the nails, causing pitting and thickening, and the scalp. Recognising the type matters because it influences which treatment is likely to help most.

Triggers and linked health

Psoriasis often runs in families, so genes play a part, but flares are usually set off by triggers. Common ones include stress, skin injury such as a cut or sunburn, certain infections, smoking, heavy alcohol use, and some medicines. Cold, dry weather can worsen it, while sunlight often helps. Importantly, psoriasis is more than skin deep. Up to a third of people develop psoriatic arthritis, causing joint pain, stiffness and swelling, so any new joint symptoms should be reported. Psoriasis is also linked to a higher risk of heart disease, diabetes, and low mood or depression. For this reason, care in the UK increasingly looks at the whole person, not just the visible patches.

How it is treated

Treatment is stepped, starting with the simplest measures. For many people, creams and ointments applied to the skin control things well, including moisturisers to reduce scaling and treatments that calm inflammation or slow skin cell growth. If these are not enough, light therapy using controlled ultraviolet light under hospital supervision can help. For more severe or widespread psoriasis, or when the joints are involved, tablets or injections that work on the immune system, including modern biologic medicines, may be used. These stronger treatments are supervised by a specialist and monitored carefully. No single treatment suits everyone, so finding the right approach is often a process of working with your GP or a dermatologist over time.

Living well with psoriasis

Because psoriasis is long-term and comes in flares, day-to-day management matters as much as medical treatment. Using moisturiser regularly, even between flares, keeps the skin comfortable and reduces scaling. Identifying and reducing personal triggers, such as stress or smoking, can lessen how often flares happen. Looking after general health, including heart health and mood, is part of good psoriasis care, not separate from it. The emotional impact is real and valid; many people find support groups or talking therapies genuinely helpful. If your psoriasis is not controlled, is spreading rapidly, or is affecting your joints, mood or daily life, it is worth returning to your GP, as treatment can nearly always be stepped up.