Psoriasis
Symptoms, Causes & Treatment
Understanding psoriasis: what causes flares, how it is graded, and the full treatment pathway from topical agents to biological therapies.
What Is Psoriasis?
Psoriasis is a chronic, immune-mediated inflammatory skin condition characterised by well-defined, raised, red or salmon-pink plaques covered with silvery-white scales. It affects approximately 2% of the UK population -- around 1.3 million people.
Psoriasis occurs because the immune system mistakenly attacks healthy skin cells, accelerating their production. Normal skin cells take approximately 28 days to mature and shed; in psoriasis, this process is compressed to 3–5 days. The rapid turnover causes cells to accumulate on the skin surface, forming the characteristic thickened, scaly plaques.
Psoriasis is not just a skin condition. It is a systemic inflammatory disease associated with an increased risk of psoriatic arthritis, cardiovascular disease, metabolic syndrome, diabetes, depression, and inflammatory bowel disease. Recognising and managing these comorbidities is an important part of psoriasis care.
Psoriasis is not contagious. It is a lifelong condition that follows a relapsing-remitting course, but effective treatments are available to control symptoms and improve quality of life. Advances in biologic therapies have transformed outcomes for people with moderate to severe disease.
What Are the Symptoms of Psoriasis?
Psoriasis symptoms vary by type and severity. Understanding the different forms helps ensure accurate diagnosis and appropriate treatment.
Raised, silvery-white scaly plaques on elbows, knees, scalp, and lower back · Dry, cracked skin that may bleed · Nail changes (pitting, ridging, onycholysis) · Itching, burning, or soreness · Psoriatic arthritis: joint pain, stiffness, swelling in some patients
Erythrodermic psoriasis: red, inflamed skin covering most of body (life-threatening temperature dysregulation) · Pustular psoriasis: pus-filled blisters · Psoriatic arthritis with rapidly progressive joint damage · Severe flare triggered by medication (lithium, beta-blockers, antimalarials)
Seek urgent assessment if psoriasis becomes suddenly widespread and red (erythrodermic), or if you develop new joint pain, stiffness, or swelling alongside psoriasis — possible psoriatic arthritis requiring early treatment.
What Causes Psoriasis?
Psoriasis is an immune-mediated condition with strong genetic and environmental triggers. Understanding what drives flares helps manage them.
Psoriasis is an immune-mediated chronic inflammatory skin disease. T-cell activation drives rapid keratinocyte proliferation (3–5 days instead of 28–30), producing the characteristic thickened plaques.
Multiple psoriasis triggers are recognised: streptococcal throat infection (especially guttate psoriasis), medications (lithium, beta-blockers, antimalarials, NSAIDs), stress, trauma (Koebner phenomenon), alcohol, and smoking.
Around 30% of people with skin psoriasis develop psoriatic arthritis — an inflammatory arthropathy with joint erosions, enthesitis, and dactylitis. It can be severe and requires DMARD treatment to prevent joint destruction.
Urticaria (hives) occurs when mast cells release histamine in response to allergens, physical triggers, infections, or medications. Most acute urticaria is idiopathic; chronic urticaria (>6 weeks) is often autoimmune.
Drug reactions cause a wide range of rashes: morbilliform (measles-like), urticaria, fixed drug eruption, and the severe Stevens-Johnson syndrome / toxic epidermal necrolysis (SJS/TEN) from antibiotics, anticonvulsants, and allopurinol.
Viral exanthems from EBV, CMV, enterovirus, rubella, and roseola cause widespread, symmetrical, non-specific rashes. Diagnosis is usually clinical. EBV rash dramatically worsens with amoxicillin.
Key Risk Factors
How Is Psoriasis Diagnosed?
Psoriasis is diagnosed clinically based on the characteristic appearance of plaques. PASI and DLQI scores grade severity. Joint X-ray or MRI investigates psoriatic arthritis. Skin biopsy confirms diagnosis in atypical cases.
How Is Psoriasis Treated?
Treatment is stepwise and matched to severity. Topical agents for mild disease; phototherapy and systemic agents for moderate; biologics for severe, treatment-resistant disease.
Supportive Measures
Emollients reduce scaling and itch. Coal tar-based products reduce inflammation. Vitamin D analogue creams (calcipotriol) are the first-line topical treatment. Avoid harsh skin products and tight clothing. Moderate sun exposure is beneficial.
Long-Term Psoriasis Management
Psoriasis is a relapsing-remitting condition. Proactive therapy between flares, identifying and avoiding personal triggers, and considering systemic or biological therapy for frequent severe flares are all part of long-term management. Psoriatic arthritis must be monitored and treated separately.
When Should You Seek Medical Advice for Psoriasis?
Erythrodermic psoriasis (widespread redness covering >90% of skin) or pustular psoriasis with systemic illness — both are dermatological emergencies requiring hospital admission.
Psoriasis significantly affects your quality of life or body image · You have joint pain alongside psoriasis · Topical treatments are not working · You wish to discuss phototherapy or biologic therapy.
How Can You Reduce Psoriasis Flares?
Psoriasis cannot be prevented, but flare frequency and severity can be reduced with lifestyle modification and trigger management.
Psoriasis is a lifelong condition that requires long-term management. Attend regular reviews, monitor for psoriatic arthritis symptoms (joint pain, stiffness), and do not stop treatments abruptly as rebound flares can occur.
Mediterranean diet reduces systemic inflammation. Weight loss of 5% significantly improves psoriasis severity. Stopping smoking and reducing alcohol each reduce plaque severity independently.
Ultraviolet (UV) phototherapy (narrow-band UVB) is highly effective for moderate-to-severe psoriasis and works well in combination with topical treatments. It is available at NHS dermatology departments.
Speak to a Clinician About Psoriasis
Through The GP Service, a licensed clinician can assess your psoriasis, prescribe appropriate treatment, and refer to dermatology for phototherapy or biologics where indicated.
Expert clinical advice, when you need it.
Psoriasis FAQs
Psoriasis is a chronic autoimmune condition and cannot be cured, but it can be very effectively managed with the right treatment. Biological therapies can achieve clear or almost-clear skin in the majority of patients with moderate-to-severe disease.
Psoriatic arthritis occurs in up to 30% of people with psoriasis. It can develop at any time — sometimes before skin symptoms appear. Joint pain, stiffness, or swelling in someone with psoriasis should always be assessed promptly to prevent joint damage.
Common triggers include stress, infections (particularly streptococcal throat infections), certain medications (beta-blockers, lithium, NSAIDs), skin injury (Köbner phenomenon), alcohol, and smoking. Identifying and managing triggers helps reduce flare frequency.
Yes. Sun exposure (in moderation, avoiding burning) is beneficial for psoriasis. UV light suppresses the overactive immune response in the skin. Phototherapy (controlled UV treatment) is an effective second-line treatment for widespread psoriasis.
Biologics (such as adalimumab, secukinumab, ixekizumab) are highly effective for moderate-to-severe psoriasis. They target specific immune pathways and can achieve clear or nearly clear skin. They are initiated by a dermatologist and require monitoring.
While psoriasis is not primarily caused by diet, an anti-inflammatory diet (Mediterranean-style), weight loss in overweight individuals, and reducing alcohol consumption all have evidence for modest improvement in disease activity.
Scalp psoriasis is treated with medicated shampoos (containing coal tar, salicylic acid, or ketoconazole), topical corticosteroids in scalp-formulation, and vitamin D analogues. Persistent cases may benefit from phototherapy or systemic treatment.
Yes. Psoriasis is associated with significantly higher rates of depression, anxiety, and social isolation. The impact on quality of life should be routinely discussed with a clinician, and psychological support should be offered where appropriate.