In psoriasis, the immune system drives skin cells to be produced far faster than they can be shed. The result is thickened, red plaques with silvery-white scale, most often on the elbows, knees, lower back and scalp. It affects roughly 2% of people worldwide.
The two things people get wrong
It is not contagious. Psoriasis cannot spread to another person through touch, shared food, shared clothing or living together. Patients are frequently excluded socially over this, and it is based on nothing.
It is not simply “dry skin” or a fungal infection. Treating psoriasis with antifungal creams — which happens often — does not help, and months are lost.
Types we see
- Chronic plaque psoriasis — the commonest form; well-defined scaly plaques
- Scalp psoriasis — thick scale along the hairline, often mistaken for severe dandruff
- Nail psoriasis — pitting, ridging, thickening or separation of the nail; sometimes the only sign
- Guttate psoriasis — sudden shower of small spots, classically after a throat infection
- Flexural (inverse) psoriasis — in skin folds; smooth and red rather than scaly
- Palmoplantar psoriasis — palms and soles; disproportionately disabling for manual work
- Pustular and erythrodermic psoriasis — uncommon but require urgent care
What triggers a flare
- Throat infection, particularly streptococcal
- Stress
- Certain medicines — including some blood pressure tablets, lithium and antimalarials
- Stopping oral steroids — a common cause of severe rebound; this is one reason psoriasis should not be treated with steroid tablets casually
- Smoking and alcohol
- Injury to the skin — plaques can appear at the site of a cut or scratch
- Dry, cold weather
Why we check more than your skin
Psoriasis is a systemic inflammatory condition, not only a skin disease. At consultation we also ask about and assess:
- Joint symptoms — around one in five to one in three patients develop psoriatic arthritis. Morning stiffness, swollen fingers or low back pain must be assessed early, because untreated joint inflammation can cause permanent damage. Always mention it.
- Metabolic health — psoriasis is associated with higher rates of diabetes, high blood pressure, abnormal lipids and cardiovascular disease, so these are worth monitoring.
- Mood — the effect on confidence and daily life is often the most significant part of the condition, and it is treated as relevant rather than incidental.
Treatment options
Treatment is stepped according to how much skin is involved and how much it affects your life:
- Topical corticosteroids with vitamin D analogues — first-line for limited disease; the combination works better than either alone
- Coal tar and salicylic acid preparations — useful for thick, scaly plaques and for the scalp
- Medicated shampoos — for scalp involvement, used with technique that matters: applied to the scalp, not just the hair, and left in place
- Emollients — unglamorous but genuinely reduce cracking, itch and scale
- Narrowband UVB phototherapy — for widespread plaque or guttate psoriasis, given as repeated sessions
- Systemic treatment — methotrexate, acitretin or ciclosporin for extensive or resistant disease, with blood monitoring
- Biologic therapy — highly effective targeted treatment for severe psoriasis; we discuss and arrange referral where it is appropriate
What to expect
Topical treatment usually improves plaques over four to eight weeks. Phototherapy and systemic treatment are judged over two to three months. Nail psoriasis is the slowest of all — nails grow slowly, so six to twelve months is a realistic horizon.
Psoriasis is controlled rather than cured. With the right treatment the skin can be completely clear for long stretches, but the underlying tendency remains and flares can happen. The goal is long periods of clear skin on as little medication as necessary — and a plan you already know how to follow when a flare starts, rather than beginning again from scratch each time.