psoriasis CT scan preparation

Overview

Psoriasis is a skin condition where skin cells grow too fast, causing thick, scaly patches. A CT scan is a type of X-ray that makes detailed cross-section images of the body. This article explains why you might have a CT scan for psoriasis and how to prepare for it safely.

Psoriasis is common, affecting between 2 and 3 out of every 100 people worldwide.

Psoriasis can start at any age, but most often appears between the ages of 15 and 35. It affects men and women equally.

Symptoms

Common symptoms

• Red or pink patches of skin with silvery-white scales
• Dry, cracked skin that may bleed or itch
• Thickened, pitted, or ridged nails
• Joint pain, stiffness, or swelling (if psoriatic arthritis is present)

Symptoms in children

• Smaller, thinner patches on the scalp, elbows, or knees
• Sometimes patches appear in skin folds like the diaper area
• May be mistaken for cradle cap or nappy rash

Symptoms in older adults

• Skin may look less red and have finer scales
• More likely to have joint symptoms or other health conditions
• Skin is often thinner, so dryness and cracking can be more painful

Causes

Main causes

• Psoriasis happens when the immune system mistakenly attacks healthy skin cells, speeding up their growth.
• Genetics play a role — it often runs in families.
• Environmental factors such as stress, infections, skin injuries, and some medicines can trigger or worsen flare-ups.

Risk factors

• Family history of psoriasis
• A trigger such as stress, throat infection, or skin injury
• Smoking or heavy alcohol use
• Certain medications — ask your doctor which ones may affect you

When to see a doctor

See a doctor urgently if:

• If you have severe skin symptoms that spread quickly and make you feel very unwell, seek medical care the same day.
• If you have any reaction to CT contrast dye, tell the radiology team immediately and follow their advice.

Book a routine appointment if:

• If you notice new or changing skin patches that last more than a few weeks, make an appointment with your doctor.
• If you have joint pain or swelling along with psoriasis, ask for a referral to a specialist.

Diagnosis

Your doctor will examine your skin, nails, and joints, and ask about your symptoms and family history. They may also take a small skin sample (biopsy) to confirm the diagnosis. A CT scan can be used to look at your joints or internal organs if there is concern about psoriatic arthritis or other complications.

Tests that may be done

• Physical exam
• Skin biopsy (a small sample of skin examined under a microscope)
• Blood tests
• CT scan (with or without contrast) to check for joint or internal organ involvement
• X-ray or ultrasound — sometimes used to look at joints

What to expect at your appointment

During a CT scan, you lie flat on a table that slides into a large ring-shaped machine. The scanner takes pictures as the table moves through. If contrast dye is needed, it is given through a small tube in your arm. You may be asked to hold your breath for a few seconds. The scan is painless and usually over in 15 to 30 minutes. Afterward, you can return to normal activities unless your doctor tells you otherwise.

Treatment

Treatment for psoriasis focuses on slowing skin cell growth and reducing inflammation. It usually includes skin creams, light therapy, and medicines that help calm the immune system. Preparing for a CT scan is separate but important: you may need to fast for a few hours, avoid caffeine, and tell your radiologist about your psoriasis, any medications, and any allergies.

Self-care at home

• Moisturise your skin daily to reduce dryness and flaking.
• Take lukewarm showers and use gentle, fragrance-free cleansers.
• Follow your CT preparation instructions: fast if told, drink only clear fluids, and stop certain supplements if requested.
• Wear comfortable, metal-free clothing to the CT scan — you'll be asked to remove jewellery, glasses, and anything with metal.

Medical treatments

Your doctor may prescribe topical creams or ointments to apply to your skin, light therapy (ultraviolet light), or oral and injectable medicines that work throughout the body to control inflammation. Never stop or change a medication without speaking to your doctor, especially before a CT scan.

When is surgery considered?

Surgery is not a standard treatment for psoriasis. If psoriatic arthritis has severely damaged a joint, joint replacement surgery might be an option, but this is only after other treatments have been tried.

Living with this condition

Living with psoriasis means taking care of your skin and your overall health. For routine scans like CT, always inform the radiology team that you have psoriasis, and tell them about any joint pain or new skin symptoms.

Lifestyle tips

• Manage stress through relaxation, hobbies, or counselling.
• Stop smoking and limit alcohol — both can trigger flare-ups.
• Protect your skin from cuts, scratches, and sunburn, which can make psoriasis worse.

Diet and exercise

No special diet cures psoriasis. Eating a balanced diet and staying physically active can support your immune system and joint health. Before a CT scan with contrast, follow your doctor's eating and drinking instructions.

Mental health and emotional wellbeing

Psoriasis can make you feel self-conscious, anxious, or down. It is normal to feel this way. Talk to your doctor or a mental health professional — support helps.

Prevention

Psoriasis itself cannot be prevented, but you may be able to reduce flare-ups by avoiding your known triggers, such as stress, alcohol, and skin injuries.

Vaccines

Some vaccines are safe and recommended for people with psoriasis. Before a CT scan, discuss your vaccination status with your doctor.

Screening programmes

There is no routine screening test for psoriasis. But if you have psoriasis, your doctor may check you regularly for psoriatic arthritis and related health conditions.

Complications

If left untreated

• Psoriatic arthritis can progress and cause permanent joint damage.
• Severe psoriasis can be painful and raise the risk of skin infections.
• Untreated psoriasis can take a toll on emotional well-being and quality of life.

Long-term outlook

Psoriasis is a long-term condition, but most people are able to manage their symptoms and live full, active lives. With the right treatment and care, flare-ups can be controlled. For those who need a CT scan, preparation is straightforward and helps ensure the test is safe and accurate.

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