Questions and Answers
What cytokine is primarily associated with autoimmunity in psoriasis?
Which treatment for psoriasis should be applied for a maximum of 8 weeks before taking a break?
In which type of psoriasis are sterile pustules commonly found?
What is a common symptom of guttate psoriasis?
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Which factor is NOT considered a risk factor for developing psoriasis?
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How should emollients be applied for psoriasis management?
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Which system is used to assess the severity of psoriasis?
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What is the purpose of IL-23 in the pathophysiology of psoriasis?
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Which type of psoriasis is characterized by red lesions without scales?
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What phenomenon describes the development of new psoriasis lesions on previously unaffected skin after injury?
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Study Notes
Pathophysiology
- Psoriasis is a chronic and relapsing inflammatory disorder affecting skin integrity.
- Elevated levels of IL-23 in the skin are linked to autoimmune responses in psoriasis.
- Antigen presenting cells release IL-23, which binds to receptors on CD4+ T cells, initiating their activation.
- Activated T cells differentiate into various cytokines, with Th1 and Th17 being significant, along with memory T cells.
- T cells enhance keratinocyte proliferation, inhibit their differentiation, and increase cytokine and chemokine secretion.
- This leads to epidermis compromise, formation of plaques with immature keratin, and reduced desmosomes.
- Memory T cells remain in the skin, providing a basis for future psoriasis episodes.
Symptoms
Plaque Psoriasis
- Characterized by symmetrical lesions that are salmon pink with silvery-white scales.
- Symptoms include nail pitting and separation from the nail bed.
Scalp Psoriasis
- Presents with varying degrees of redness and inflammation; can be mild to severe.
Pustular Psoriasis
- Exhibits sterile pustules primarily on the arms and feet.
Seborrhoeic Psoriasis
- Lesions appear in the groin and armpit regions, often without scales.
Guttate Psoriasis
- Features small, scattered lesions mainly on the trunk and limbs.
- Commonly occurs after strep throat in adolescents and is typically self-limiting.
Erythrodermic Psoriasis
- Involves extensive red skin with very few classic lesions, presenting severe systemic symptoms like fever and joint pain.
Lichen Planus
- Resembles psoriasis but typically lacks a family history link.
Risk Factors
- Can arise from genetic predisposition and various environmental triggers.
- Key environmental factors include infections, medications, obesity, alcohol consumption, physical inactivity, smoking, and emotional stress.
- Lesions may develop following trauma or stress, known as the Koebner phenomenon, where new lesions appear on previously unaffected skin.
Treatment
Severity Assessments
- PASI scoring system: Mild (10), Moderate (10-20), Severe (20+).
- Assessment includes body surface area and dermatology-specific quality of life index.
Topical Treatments
- Corticosteroids: Used for a maximum of 8 weeks, followed by a break.
- Vitamin D analogues (e.g., Calcipotriol): Prescription only; used for trunk/limbs, applied OD/BD for up to 8 weeks.
- Coal tar: Available as some GSL/P; applied 2-3 times a week but may stain.
- Dithranol: Start low and titrate, must be washed off after 30-60 minutes.
- Salicylic acid: Used on the scalp with a thin layer for up to 3 months.
Phototherapy
- Involves UVB or PUVA treatments.
Systemic Therapy
- Primarily methotrexate, with other options like ciclosporin, acitretin, TNF-α, IL-12, IL-23, and IL-17 antagonists.
- NICE guidelines recommend starting with a potent topical steroid and a vitamin D analogue administered at different times.
Counselling Points
- Daily use of emollients is crucial; patients should find a preferred moisturizer for the entire body.
- Apply emollients with smooth strokes in the direction of hair growth; carry some for dry or itchy moments.
- Advise against scratching or picking at lesions, and ensure patients understand the application separation of topical treatments and emollients.
- Patients should note the typical progression of treatment: scaling will resolve first, followed by a color change to normal.
- Patients should cease topical treatments once the skin is clear, particularly corticosteroids.
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Description
This quiz delves into the complex pathophysiology of psoriasis, focusing on its chronic inflammatory nature and the role of IL-23 in autoimmunity. It explores how activated T cells and cytokines interact with keratinocytes during the disease process. Test your understanding of these mechanisms and their implications in psoriasis treatment.
