Dermatology for MRCP Part 1

A 30-year-old man has well-demarcated red plaques with silvery scale over both elbows, knees and his scalp. His fingernails show pitting and separation of the nail from the bed. The plaques are only mildly itchy. What is the most likely diagnosis?

1. Lichen planus Purple, flat-topped, itchy papules. Well-demarcated silvery-scaled extensor plaques with nail pitting makes it a consideration.
2. Cutaneous T-cell lymphoma Persistent patches mimicking eczema or psoriasis. Well-demarcated silvery-scaled extensor plaques with nail pitting raises it.
3. Seborrhoeic dermatitis Greasy scale in seborrhoeic areas. Well-demarcated silvery-scaled extensor plaques with nail pitting redirects it.
4. Eczema Itchy, poorly demarcated, flexural inflammation. Well-demarcated silvery-scaled extensor plaques with nail pitting separates it.
5. Psoriasis correct Correct. Well-demarcated silvery-scaled plaques on the extensor surfaces with nail pitting are chronic plaque psoriasis.

The point: Psoriasis is a common chronic immune-mediated inflammatory skin disease driven by T-cell activation and rapid keratinocyte turnover. The commonest form, chronic plaque psoriasis, gives well-demarcated red plaques with silvery scale over the extensor surfaces, scalp and behind the ears, with nail changes such as pitting and onycholysis. Other patterns are guttate psoriasis (small drop-like lesions after a streptococcal throat infection), flexural (inverse) psoriasis, pustular and the rare emergency of erythrodermic psoriasis. Up to a third develop psoriatic arthritis, so joints should be screened, and there is an association with metabolic syndrome and cardiovascular risk. Triggers include streptococcal infection, stress, trauma (the Koebner phenomenon), and drugs such as beta-blockers, lithium and antimalarials, with a rebound flare on stopping systemic steroids. First-line treatment of plaque disease is topical: a potent corticosteroid plus a vitamin D analogue such as calcipotriol. When topical therapy is insufficient, phototherapy and then systemic agents (methotrexate, ciclosporin, acitretin) or biologics are used under specialist care. It is a lifelong relapsing condition managed to control rather than cure, with attention to the associated joint and cardiovascular risks.

Source: NICE CG153 — psoriasis: assessment and management NICE · tier 1, national regulator or guidance

A 30-year-old man has well-demarcated red plaques with silvery scale over both elbows, knees and his scalp. His fingernails show pitting and separation of the nail from the bed. The plaques are only mildly itchy. What is the most appropriate investigation?

1. Skin biopsy only if the diagnosis is unclear For atypical cases. Well-demarcated silvery-scaled extensor plaques with nail pitting makes it selective.
2. Clinical diagnosis from the appearance and distribution correct Correct. Psoriasis is diagnosed clinically from its appearance and distribution.
3. Screen for psoriatic arthritis Because it is common. Well-demarcated silvery-scaled extensor plaques with nail pitting makes it important.
4. Throat swab in guttate psoriasis For a streptococcal trigger. Well-demarcated silvery-scaled extensor plaques with nail pitting makes it directed.
5. Assess cardiovascular and metabolic risk Because of the associations. Well-demarcated silvery-scaled extensor plaques with nail pitting makes it thorough.

The point: Psoriasis is a common chronic immune-mediated inflammatory skin disease driven by T-cell activation and rapid keratinocyte turnover. The commonest form, chronic plaque psoriasis, gives well-demarcated red plaques with silvery scale over the extensor surfaces, scalp and behind the ears, with nail changes such as pitting and onycholysis. Other patterns are guttate psoriasis (small drop-like lesions after a streptococcal throat infection), flexural (inverse) psoriasis, pustular and the rare emergency of erythrodermic psoriasis. Up to a third develop psoriatic arthritis, so joints should be screened, and there is an association with metabolic syndrome and cardiovascular risk. Triggers include streptococcal infection, stress, trauma (the Koebner phenomenon), and drugs such as beta-blockers, lithium and antimalarials, with a rebound flare on stopping systemic steroids. First-line treatment of plaque disease is topical: a potent corticosteroid plus a vitamin D analogue such as calcipotriol. When topical therapy is insufficient, phototherapy and then systemic agents (methotrexate, ciclosporin, acitretin) or biologics are used under specialist care. It is a lifelong relapsing condition managed to control rather than cure, with attention to the associated joint and cardiovascular risks.

Source: NICE CG153 — psoriasis: assessment and management NICE · tier 1, national regulator or guidance

A 30-year-old man has well-demarcated red plaques with silvery scale over both elbows, knees and his scalp. His fingernails show pitting and separation of the nail from the bed. The plaques are only mildly itchy. What is the most appropriate management?

1. Biologic therapy for severe disease When other treatments fail. Well-demarcated silvery-scaled extensor plaques with nail pitting makes it targeted.
2. Phototherapy when topical treatment is insufficient Phototherapy is the next step when topical treatment is insufficient, and well-demarcated silvery-scaled extensor plaques with nail pitting here points elsewhere.
3. Emollients and scalp preparations For symptom control. Well-demarcated silvery-scaled extensor plaques with nail pitting makes it supportive.
4. Potent topical corticosteroid with a vitamin D analogue correct Correct. First-line treatment of plaque psoriasis is a potent topical steroid with a vitamin D analogue.
5. Systemic agents such as methotrexate under specialist care For extensive or resistant disease. Well-demarcated silvery-scaled extensor plaques with nail pitting makes it specialist.

The point: Psoriasis is a common chronic immune-mediated inflammatory skin disease driven by T-cell activation and rapid keratinocyte turnover. The commonest form, chronic plaque psoriasis, gives well-demarcated red plaques with silvery scale over the extensor surfaces, scalp and behind the ears, with nail changes such as pitting and onycholysis. Other patterns are guttate psoriasis (small drop-like lesions after a streptococcal throat infection), flexural (inverse) psoriasis, pustular and the rare emergency of erythrodermic psoriasis. Up to a third develop psoriatic arthritis, so joints should be screened, and there is an association with metabolic syndrome and cardiovascular risk. Triggers include streptococcal infection, stress, trauma (the Koebner phenomenon), and drugs such as beta-blockers, lithium and antimalarials, with a rebound flare on stopping systemic steroids. First-line treatment of plaque disease is topical: a potent corticosteroid plus a vitamin D analogue such as calcipotriol. When topical therapy is insufficient, phototherapy and then systemic agents (methotrexate, ciclosporin, acitretin) or biologics are used under specialist care. It is a lifelong relapsing condition managed to control rather than cure, with attention to the associated joint and cardiovascular risks.

Source: NICE CG153 — psoriasis: assessment and management NICE · tier 1, national regulator or guidance