plaque psoriasis

23 Jul

Plaque psoriasis is a chronic autoimmune skin condition that is caused by the rapid buildup of skin cells on the surface. Presentations include thick, raised, and scaly patches known as plaques. These plaques are typically red or pink in colour and can be covered with silvery-white scales. The condition most commonly affects the elbows, knees, scalp, lower back, and nails. Plaque psoriasis can cause itching, pain, and discomfort. The aim of treatment is to manage symptoms and reduce inflammation.

- In the US, approximately 2% of the population is affected by plaque psoriasis
- Some ethnic minority populations have a very low prevalence of plaque psoriasis such as Japanese, aboriginal Australians and Indian located in South America [1]
- Psoriasis affects 1.3-2.8% of the UK population
- Long term plaque psoriasis is the most common types of psoriasis
- According to NICE, 80-90% of people affected by psoriasis have it in plaque form [2]
- Immune system attacking healthy cells (auto-immune conditions)
- Inheritance from families
- Injury to the skin
- Drinking excessive amounts of alcohol
- Smoking
- Stress
- Hormonal changes
- Throat infections
- HIV
- Medicines like lithium, ACE inhibitors etc [3]
Medical students
- The hallmark of psoriasis is sustained inflammation that leads to uncontrolled keratinocyte proliferation and dysfunctional differentiation.
- The histology of the psoriatic plaque shows epidermal hyperplasia and inflammatory infiltrates composed of dermal dendritic cells, macrophages, T cells, and neutrophils
- Neovascularization is also a prominent feature.
- The inflammatory pathways active in plaque psoriasis and the rest of the clinical variants overlap, but also display discrete differences
- Disturbances in the innate and adaptive cutaneous immune responses are responsible for the development and sustainment of psoriatic inflammation
Patients
- Psoriasis is caused by long-lasting inflammation in the skin.
- This inflammation makes skin cells grow too fast and not mature properly, leading to thick, scaly patches.
- Under the microscope, these patches show too much skin tissue and a buildup of immune cells (like T cells and neutrophils) that are meant to fight infection.
- New blood vessels also grow in the area, which is part of the body's immune reaction.
- Psoriasis involves a mix of the body’s natural defences (innate immunity) and learned immune responses (adaptive immunity), both of which become overactive and keep the inflammation going.
- Different types of psoriasis share some of the same causes, but also have unique differences in how the immune system reacts.
- Tobacco
- Alcohol
- Obesity
- Infections (eg. streptococcus triggers guttate psoriasis)
- Drugs such as beta blockers and lithium
- Stress
- Weather (cold conditions)
- Koebner’s phenomenon- presense/ reproduction of skin lesions at the areas of injury [5]
- Elevated patches and areas of skin
- Palpable lesions (can be touched)
- Large surface area
- Silver, thick and shiny scales are found on the patches
- Dark purple appearance of lesions on darker skin [6]
- Clinical examination of appearance and history of symptoms, nail, joint problems and family history of psoriasis
- Exploration into recent changes in life such as stress or illness
- Skin biopsy (sample taken from skin) to confirm a diagnosis of psoriasis [7]
- Discoid eczema- inflammatory skin condition
- Tinea corporis- also known as ringworm
- Psoriasis rosea- tree distribution of plaques
- Seborrhoeic dermatitis- flaky skin found on the scalp, face and upper trunk
- Drug-induced psoriasis
- Follicular problems such as inflammation and psoriasis rubra pilaris which involves the follicles [8]
Medical Student
- Consider patient preferences, cosmetic acceptability, practicality, and extent of skin involvement.
- Discuss available formulations; ointments preferred for scaly plaques.
- Consider referral for phototherapy or systemic therapy if topical treatment is inadequate.
- Review timeline: Adults at 4 weeks; children at 2 weeks post-initiation of therapy.
- Assess treatment response, tolerability, and adherence.
- Reinforce corticosteroid breaks between treatment courses.
- Daily use of potent corticosteroids → consider need for systemic therapy.
- If response is inadequate address adherence or formulation issues or prescribe an alternative formulation if needed.
- Annual review if adults use potent/very potent corticosteroids or children use any form of corticosteroid.
- Emollients: Improve dryness, scaling, and support barrier function. May be sufficient in mild psoriasis.
- Soap substitutes: Aqueous cream may improve symptoms.
- Coal tar: Anti-inflammatory/anti-scaling; limited by irritation and staining.
- Dithranol: For thick plaques; used as short-contact therapy (10–30 min). Also useful in scalp psoriasis.
- Salicylic acid: Keratolytic; improves scale shedding and enhances absorption of other agents. Avoid in pregnancy.
- Calcipotriol: First-line; often combined with betamethasone dipropionate. May irritate sensitive areas.
- Corticosteroids: Anti-inflammatory, antiproliferative, immunosuppressive.
- Do not use potent/very potent corticosteroids continuously >4 weeks.
- Use alternatives during breaks (e.g. calcipotriol or coal tar).
- Not suitable for children if very potent.
Patients
- Your doctor will consider what’s practical for you, your preferences, how visible or widespread your psoriasis is, and how comfortable a treatment is on your skin.
- Some treatments come as ointments, creams, or gels. Ointments are often best for dry, scaly patches.
- Moisturisers (emollients): Help with dryness, scaling, and protect your skin. Sometimes this is enough for mild cases.
- Soap substitutes: Such as aqueous cream, can reduce dryness and irritation.
- Coal tar: Reduces inflammation and scaling, but may stain clothes and can irritate skin.
- Dithranol: Used for thick plaques, especially on the scalp. It’s applied for a short time (10–30 minutes).
- Salicylic acid: Helps shed scales and makes other treatments work better. Avoid if you're pregnant.
- Calcipotriol: A vitamin D-based cream used as a first option, often combined with a steroid. Avoid on sensitive areas as it can sting.
- Steroid creams (corticosteroids): Reduce redness and swelling. Should not be used every day for long periods—usually no more than 4 weeks at a time.
- Adults are usually reviewed 4 weeks after starting a new treatment.
- Children are reviewed after 2 weeks.
- Tobacco
- Alcohol
- Obesity
- Infections (eg. streptococcus triggers guttate psoriasis)
- Drugs such as beta blockers and lithium
- Stress
- Weather (cold conditions)
- Koebner’s phenomenon- presense/ reproduction of skin lesions at the areas of injury [5]
- Psoriasis is contagious
- There is only one type of psoriasis
- It is a product of poor hygiene
- Psoriasis is the same as eczema
- Severity is determined by the amount of skin covered in plaques [10,11]
- How did I get this form of psoriasis?
- Is there anything I can do to manage symptoms?
- Will be treatment change if I am on medications already?
- What are the possible side effects of treatment?
- How long does it take for treatment to be effective?
- National Psoriasis Foundation
- British Skin Foundation
- Psoriasis and Psoriatic Arthritis Alliance
[1] Psoriasis: epidemiology, clinical features, and quality of life
[2] NICE: Psoriasis
[3] NHS Causes: Psoriasis
[4] Psoriasis Pathogenesis and Treatment
[5] Psoriasis: Triggering factors
[6] MSD Manual: Plaque Psoriasis
[7] Psoriasis: Diagnosis and treatment
[8] Psoriasis overview
[9] Guidelines for the management of psoriasis
[10] Medical Myths: All about psoriasis
[11] What you may not know about Psoriasis