Psoriasis, explained without alarm
The two things patients most need to hear about psoriasis are that nobody can catch it from them, and that treatment has improved dramatically. Both get lost under a great deal of misinformation.
Psoriasis is a chronic immune-mediated condition in which skin cells multiply far faster than normal — days instead of weeks — producing thick, scaly plaques. It affects roughly 2 to 3 percent of people worldwide, and it has a strong genetic component.
Three things to be clear about
- It is not contagious. Nobody can catch psoriasis by touching you, sharing a towel, or swimming in the same water. This misunderstanding causes more social distress than the disease itself in many patients.
- It is not caused by poor hygiene or by anything you did wrong.
- It is a systemic condition, not just a skin one. That matters for your general health, as below.
Recognising it
Classic plaque psoriasis: well-defined, raised, red plaques with thick silvery-white scale, symmetrically distributed on elbows, knees, lower back and scalp. Often itchy, sometimes painful, and plaques may crack and bleed.
Distinguishing features from eczema: sharper borders, thicker and more silvery scale, typical locations on extensor surfaces (elbows, knees) rather than flexures, and associated nail changes — pitting, thickening, or the nail lifting from its bed.
Other types include scalp psoriasis (thick plaques extending past the hairline, often mistaken for dandruff), guttate psoriasis (small drop-like lesions, classically after a streptococcal throat infection), inverse psoriasis (smooth, shiny, in skin folds), pustular and erythrodermic psoriasis (both uncommon and both medical emergencies).
Why it is more than skin
Associations worth screening for
- Psoriatic arthritis affects up to a third of patients. Joint pain and stiffness, particularly morning stiffness lasting over 30 minutes, or swollen fingers and toes, need assessment promptly — joint damage can be permanent, and early treatment prevents it. Please mention joint symptoms even if you came about your skin.
- Cardiovascular disease, diabetes, obesity and fatty liver are all more common in psoriasis, because chronic inflammation is systemic. Blood pressure, sugar and lipid checks are part of proper care.
- Depression and anxiety are substantially more common, and not simply because of appearance. This deserves treating in its own right.
Common triggers
- Streptococcal throat infection — a classic trigger for guttate psoriasis
- Stress, which is genuinely bidirectional
- Skin injury, including scratching, tattoos and sunburn (the Koebner phenomenon)
- Certain medications: beta-blockers, lithium, antimalarials, and abrupt withdrawal of oral steroids
- Smoking and alcohol, both of which worsen severity and reduce treatment response
- Obesity
- Weather — usually better in sun and humidity, so many patients in Kerala do comparatively well, with winter and air-conditioned environments being worse
Treatment, which has changed a great deal
Mild to moderate — topical
Topical steroids of appropriate potency for the site; vitamin D analogues such as calcipotriol, often combined with a steroid; coal tar; salicylic acid to reduce scale; calcineurin inhibitors for the face and folds; and generous moisturisers, which genuinely reduce cracking and itch.
Moderate to severe
- Phototherapy (narrowband UVB) — effective, well established, requires clinic visits two or three times weekly.
- Methotrexate — long-standing, effective, needs blood monitoring. Absolutely contraindicated in pregnancy, for both partners.
- Ciclosporin — rapid effect, used short term, needs blood pressure and kidney monitoring.
- Acitretin — a retinoid; not for women who may conceive, with a long exclusion period afterwards.
- Apremilast — oral, generally well tolerated.
- Biologics — targeted injections against TNF-alpha, IL-17, IL-23 or IL-12/23. These have genuinely transformed severe psoriasis; many patients achieve almost clear skin. They require screening for tuberculosis and hepatitis before starting, which matters particularly in India, and they are expensive — though biosimilars have improved access.
What to expect long term
Psoriasis is a lifelong condition that comes and goes, and it is controlled rather than cured. That sounds discouraging, but the practical reality for most patients today is quite good: with the right treatment, long periods of clear or nearly clear skin are a realistic goal, in a way they were not a decade ago.
Two things I ask patients to avoid: stopping oral steroids abruptly, which can trigger a severe flare, and unregulated "herbal" treatments that turn out to contain undeclared steroids — a common and avoidable cause of rebound. If your psoriasis is widespread, painful, affecting your joints, or affecting your mood, that is a reason to be seen rather than to manage alone.
Frequently asked questions
No. Psoriasis is an immune-mediated condition, not an infection, and nobody can catch it from touching you, sharing towels or swimming together. This misunderstanding causes many patients more distress than the disease itself.
It cannot be cured, but it is controlled well. With modern treatment, including biologics for severe disease, long periods of clear or almost clear skin are a realistic goal in a way they were not ten years ago.
Psoriasis has sharper borders, thicker silvery scale, typically appears on elbows, knees, lower back and scalp, and often causes nail pitting or thickening. Eczema is itchier, less well defined, and favours skin creases such as the inner elbows and behind the knees.
Up to a third of patients develop psoriatic arthritis. Morning stiffness lasting over 30 minutes, joint pain, or swollen fingers and toes need prompt assessment, because joint damage can be permanent and early treatment prevents it.
Streptococcal throat infection, stress, skin injury including scratching and sunburn, certain medications such as beta-blockers and lithium, abrupt withdrawal of oral steroids, smoking, alcohol and obesity. Many patients improve in sun and humidity.
Unregulated ones often are not. Some contain undeclared steroids, which produce quick improvement followed by a severe rebound flare when stopped. Any treatment that clears psoriasis dramatically within days is worth having checked.
