Psoriasis
Psoriasis looks like patches of thickened skin covered in firm scale, usually on the elbows, knees, scalp and lower back.
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Medicines commonly prescribed for Psoriasis
For informational purposes only. Always consult a doctor before using any medicine.
Dosage form: INJECTABLE PERFUSION, 130 mg/26 mlActive substance: ustekinumabManufacturer: Biosimilar Collaborations Ireland LimitedPrescription requiredDosage form: INJECTABLE, 130 mgActive substance: ustekinumabManufacturer: Fresenius Kabi Deutschland GmbhPrescription requiredDosage form: INJECTABLE, 45 mgActive substance: ustekinumabManufacturer: Amgen Technology (Ireland) Unlimited CompanyPrescription required
Psoriasis looks like patches of thickened skin covered in firm scale, usually on the elbows, knees, scalp and lower back. It is not contagious: you cannot catch it from a handshake, a shared towel or a swimming pool, and that is the first thing worth knowing yourself and saying to the people around you. It affects roughly two people in a hundred and tends to start either in the twenties or closer to sixty. What follows is how it looks and why it happens, which forms of it need an ambulance rather than an appointment, how it is treated today, and what else is going on beyond the skin.
What appears on the skin
The classic picture is a dry raised plaque with a sharp edge. On pale skin it looks pink or red with white or silvery scale; on brown and black skin it tends towards purple or dark brown and the scale looks grey, which is why psoriasis on darker skin is often recognised later. Lift a scale carefully and underneath there is a shiny pink surface that beads with tiny spots of blood.
The favourite sites are predictable: the outer surface of the elbows and knees, the scalp, the lower back, around the navel, the skin behind the ears. But plaques can turn up anywhere, including the groin, under the breasts, on the palms and on the genitals.
How it feels varies. Some people notice nothing beyond dryness; in others the plaques itch or hurt, and the skin over the joints cracks and bleeds. The nails deserve a separate look: in about half of people with psoriasis they develop pinprick dents, the nail plate clouds over, yellows, thickens or lifts away from the bed. Nails are often the only clue when the skin is almost clear.
Psoriasis runs in waves: weeks or months of quiet, then a flare, then relief again. The waves cannot be fully predicted, but most people work out in time what sets theirs off.
Why the skin renews faster than it should
Normally a skin cell is born in the deepest layer, travels upwards, dies and sheds unnoticed, and the whole journey takes three to four weeks. In psoriasis it takes three to seven days. Immature cells have no time to shed and pile up on one another, and that pile is the scaly plaque.
What drives the production line is the person's own immune system. T cells, whose job is to hunt bacteria and viruses, mistake healthy skin for an enemy and keep it permanently inflamed. So psoriasis is not dirty skin or the result of poor washing, and an antibiotic cream will not clear it.
The tendency runs in families: a close relative with psoriasis raises the odds. But there is no single gene, there are dozens, and carrying an unlucky set does not mean the condition will ever show itself. Something usually has to push it into the open.
The different types of psoriasis
The type shapes both the look of the rash and the approach to treatment, which is why it is named in the diagnosis.
- Plaque psoriasis. The commonest by far, nine cases in ten. Those firm scaly plaques on the elbows, knees and lower back.
- Scalp psoriasis. A variant of the plaque type. Thick scale in the hair, often creeping onto the forehead and behind the ears, and easily mistaken for stubborn dandruff. Hair can thin temporarily, usually from scratching rather than from the condition itself.
- Guttate psoriasis. A sudden shower of small spots under a centimetre across the trunk, arms and legs. It appears mainly in children and young adults one to three weeks after a sore throat and in many cases clears completely within a few weeks.
- Flexural or inverse psoriasis. Smooth, shiny red patches with no scale in the armpits, under the breasts, in the groin and between the buttocks. Friction and sweat make it worse, and it mimics a fungal rash so closely that it spends months being treated as the wrong thing.
- Palmoplantar pustulosis. Yellowish pus-filled blisters on the palms and soles that dry into brown crusts. The pus is sterile; this is not an infection. It is hard to live with and closely tied to smoking.
- Nail psoriasis. It can be the only sign there is. It is also the feature that most often heralds trouble in the joints.
When it becomes an emergency
Two rare forms of psoriasis are life-threatening, and it pays to recognise them early.
- Erythrodermic psoriasis. Almost the whole skin turns red and starts to peel. Through skin like that the body loses heat, water and protein, so shivering, swinging temperature, swelling, weakness and a racing heart follow. Older people tolerate it especially badly.
- Generalised pustular psoriasis. Over hours or days tiny pustules erupt across wide areas of skin and run together into lakes of pus. At the same time the temperature climbs, chills set in and exhaustion takes over.
Both need admission to hospital rather than a dermatology appointment in a fortnight: call an ambulance (in Spain, Italy, Portugal, Poland and Ukraine the single European number 112 applies). Note one common trigger for such a flare as well: steroid tablets or injections stopped abruptly. That is precisely why systemic steroids are not prescribed for psoriasis, because when they are withdrawn the disease returns far worse. If such medicines have been prescribed to you for another reason, never stop them on your own.
What sets off a flare
The trigger differs from person to person, but the list of repeat offenders is short:
- damage to the skin from a cut, a graze, a tattoo, a bite or sunburn, with a plaque appearing on that very spot one to three weeks later;
- a streptococcal sore throat, particularly in teenagers and young adults;
- heavy or prolonged stress and lack of sleep;
- smoking and regular alcohol, which also get in the way of treatment working;
- excess weight, since fat tissue sustains inflammation in its own right;
- hormonal shifts at puberty, after childbirth and around the menopause;
- certain medicines: lithium, beta blockers, antimalarials, ACE inhibitors, and the withdrawal of systemic steroids;
- cold dry winter air and indoor heating.
Spotting your own triggers is easier if you spend a couple of months noting what came before each downturn. Go through the medicine list with a doctor rather than stopping anything yourself: the benefit of a beta blocker after a heart attack may well outweigh a spoiled patch of skin.
How it is treated
The diagnosis is made by eye, from the look and the distribution of the rash; a skin biopsy is rarely needed. There is no cure, but clear or almost clear skin is now a realistic outcome for most people. Treatment is chosen by type, by how much skin is involved and by how far the condition interferes with daily life.
- Topical treatments. First line when the area is small. Steroid creams and ointments of varying strength, vitamin D analogues, combinations of the two, salicylic acid preparations to soften the scale, and coal tar. Strong steroids are not put on the face, in the skin folds or on the genitals; there you use mild ones in short courses, or calcineurin inhibitors. Do not judge the effect before a month to six weeks have passed.
- Phototherapy. Narrowband ultraviolet light given at a clinic, usually two or three times a week as a course. It works well for widespread plaques and for the guttate form. A sunbed is not a substitute: the spectrum is different and the risk to the skin is higher.
- Systemic tablets. For severe disease: methotrexate, ciclosporin, the retinoid acitretin, and newer drugs that damp the inflammation from within. All of them call for regular blood tests and monitoring of the liver and kidneys. Methotrexate and acitretin harm an unborn baby: time has to pass after stopping them before trying to conceive, and the intervals differ for men and women. If pregnancy is a possibility, say so before the first prescription rather than after.
- Biological medicines. Injections that block specific links in the inflammatory chain. A specialist prescribes them when earlier lines have not worked. Latent tuberculosis and hepatitis are screened for beforehand, and during treatment any infection with a high temperature should be shown to a doctor sooner than you otherwise would.
Everyday skin care
Between courses of treatment it is routine that keeps the skin in order, and it matters more than it looks.
- Emollients are the foundation. Use them generously and every day, even when the skin is clear: a moisturised plaque itches less, cracks less and responds better to medicines. After a shower, apply within the first few minutes onto damp skin.
- Wash in warm rather than hot water and swap ordinary soap for an unperfumed product.
- Soften scale with cream instead of picking it off: damaging the skin breeds a fresh plaque.
- Moderate sunshine helps many people, but sunburn reliably makes things worse.
- Stopping smoking is worth the effort; in palmoplantar disease it is sometimes the only thing that turns the tide.
- Losing weight noticeably improves both the skin and the response to medication.
- Keep using treatment as prescribed even once things improve: on-and-off use is the commonest reason an ointment seems to have stopped working.
Joints, blood vessels and mood
Psoriasis does not live in the skin alone. In roughly one person in five the joints eventually become inflamed, which is psoriatic arthritis, and the damage it does is permanent if it is left alone. Tell your doctor and ask to be referred to a rheumatologist if any of the following turns up:
- pain and swelling in a joint lasting more than six weeks;
- morning stiffness of more than half an hour that eases with movement;
- a whole finger or toe swollen like a sausage;
- pain in the heel or in the sole right beside the heel;
- back pain that bites at night and towards morning, wakes you, and loosens off by the middle of the day.
Psoriasis also carries a slightly higher risk of high blood pressure, diabetes and heart disease, so it makes sense to have blood pressure, glucose and cholesterol checked regularly. And one more thing that is not always said out loud: a condition people can see takes a toll on self-esteem. Anxiety and low mood here are not weakness but a common part of the picture, and they are treated as readily as the skin is.
Online consultation
A great deal of what psoriasis raises does not need a face-to-face visit. Online it is easy to show the rash in a photograph and work out whether it looks like psoriasis or more like eczema or a fungal infection; to understand why an ointment is not working, whether the drug is failing or the way it is applied; to weigh up asking for phototherapy or a dermatology referral for systemic treatment; to check whether a flare lines up with a new medicine; to decide what to do about the joints and whom to see. A face-to-face examination is still needed if the rash changes in an unusual way, and an ambulance if almost the whole skin suddenly reddens or a pustular rash comes with a fever.
This material is for information only and does not replace medical advice.
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