Introduction
Psoriasis is a chronic immune-mediated skin disease causing red, scaly plaques on elbows, knees, scalp, and other areas. Skin cells turnover accelerates, building thick silvery scales on inflamed patches.
It affects roughly 2–3% of people worldwide and may begin at any age, often between 15 and 25. Psoriasis is not contagious—it results from genetic and environmental triggers activating immune pathways in skin.
Up to 30% develop psoriatic arthritis. Associated conditions include cardiovascular disease, diabetes, and depression. Treatment ranges from topicals to phototherapy and biologic agents.
This page explains types, symptoms, triggers, diagnosis, and management of psoriasis.
Overview
Plaque psoriasis (psoriasis vulgaris) accounts for about 90% of cases. Other forms include guttate, inverse, pustular, and erythrodermic psoriasis.
TNF, IL-17, and IL-23 pathways are therapeutic targets in moderate-severe disease.
- Chronic immune-mediated skin disorder
- Red plaques with silvery scale
- Elbows, knees, scalp commonly affected
- Not contagious—genetic and trigger related
- Psoriatic arthritis risk up to 30%
- Topicals, phototherapy, biologics available
What happens in the body
T-cells and dendritic cells in skin release cytokines (TNF-alpha, IL-17, IL-23) that drive keratinocyte hyperproliferation. Normal skin matures in ~28 days; psoriatic skin turns over in days.
Triggers—stress, strep infection, skin injury (Koebner phenomenon), medications—flare existing disease in genetically susceptible individuals.
- Immune cytokines accelerate skin turnover
- Thickened epidermis forms scales
- Chronic inflammation affects joints in subset
- Triggers activate flares in predisposed people
- Systemic inflammation links to cardiovascular risk
Signs and symptoms
Skin and nail features include:
- Red raised patches with silvery-white scale
- Itching, burning, or soreness of plaques
- Dry, cracked skin that may bleed
- Scalp scaling resembling dandruff
- Pitting, ridging, or separation of nails
- Joint pain and swelling if psoriatic arthritis develops
- Guttate droplet lesions after strep throat
- Pustules on hands/feet in pustular type
Causes and risk factors
Multifactorial with known triggers:
- Genetic predisposition—family history common
- Immune system dysregulation—not infection
- Stress, skin injury, cold dry weather
- Streptococcal throat infection triggering guttate psoriasis
- Medications: lithium, beta-blockers, antimalarials
- Smoking and heavy alcohol use
- Obesity and metabolic syndrome associations
Diagnosis and evaluation
Clinical diagnosis often sufficient:
- Typical plaque morphology and distribution on exam
- Skin biopsy when diagnosis uncertain
- Nail and scalp exam for psoriatic features
- Screen for psoriatic arthritis symptoms and joint exam
- Differentiate from eczema, fungal infection, seborrheic dermatitis
- PASI score and body surface area for treatment planning
- Evaluate cardiovascular risk factors
Treatment and management
Stepwise by severity and joint involvement:
- Topical corticosteroids and vitamin D analogues for mild disease
- Topical calcineurin inhibitors for face and folds
- Phototherapy (narrowband UVB) for moderate plaque psoriasis
- Methotrexate, cyclosporine for moderate-severe non-biologic options
- Biologics targeting TNF, IL-17, or IL-23 for moderate-severe or psoriatic arthritis
- Co-manage psoriatic arthritis with rheumatology—DMARDs and biologics
- Moisturizers, tar preparations, and salicylic acid for scale removal
- Treat triggers: strep eradication, smoking cessation, weight management
Prevention, self-care, and lifestyle
Not every condition is fully preventable, but the steps below may lower risk or recurrence:
- Cannot fully prevent in genetically predisposed
- Identify and minimize personal triggers
- Skin injury protection to avoid Koebner flares
- Maintain healthy weight and blood pressure
- Regular follow-up for joint symptoms early
Possible complications
Delay, missed care, or unsafe self-medication can raise the chance of complications in some cases:
- Psoriatic arthritis and joint destruction
- Erythrodermic or generalized pustular psoriasis emergencies
- Increased cardiovascular and metabolic disease risk
- Depression and reduced quality of life from visible skin disease
- Side effects of systemic and biologic therapy monitoring needed
When to see a doctor or seek emergency care
Seek prompt medical advice or emergency care if any of the following apply—it is safer not to wait and see:
- Widespread or painful plaques not controlled by topicals
- Joint pain, stiffness, or swelling with skin psoriasis
- Sudden widespread redness covering most of body
- Fever with pustular psoriasis
- Significant impact on sleep, work, or mental health
Living with the condition
Psoriasis is lifelong but controllable for most. Written flare plans and consistent moisturizing reduce day-to-day burden. Sun protection remains important during phototherapy periods.
Open discussion with dermatology about biologics when quality of life suffers despite topicals helps align treatment with goals.
Frequently asked questions
Is psoriasis contagious?
No. You cannot catch it from skin contact—it is an immune-mediated condition.
Will sun help?
Moderate sun exposure helps some patients; avoid burns which can trigger Koebner flares. Medical phototherapy is controlled dosing.
Can diet cure psoriasis?
No cure from diet alone, but weight loss and anti-inflammatory eating may improve severity alongside medical treatment.
Important caution
This article is general health education in English. It is not personal medical advice or dermatology prescription.
Widespread skin failure or pustular psoriasis with fever needs urgent care.
Joint symptoms with psoriasis warrant rheumatology referral.