Dermatology for PLAB 1

A 3 year old boy has itchy dry skin in the elbow and knee creases with excoriation, present since infancy and worse in winter. His mother has asthma. His mother uses a 30 g tube of emollient which lasts about a month, and applies hydrocortisone 1% to the flexures during flares. He sleeps poorly because of the itching. What is the SINGLE most likely diagnosis?

1. Seborrhoeic dermatitis Greasy scale on the scalp, eyebrows and nasolabial folds, and cradle cap in infants. A 30 g tube of emollient lasting a month in widespread eczema makes it plausible.
2. Psoriasis Well-demarcated salmon-pink plaques with silvery scale on extensor surfaces and the scalp, and it is less itchy. A 30 g tube of emollient lasting a month in widespread eczema argues against it.
3. Bacterial superinfection of eczema Weeping, golden crusting and pustules on a background of known eczema. A 30 g tube of emollient lasting a month in widespread eczema describes it.
4. Atopic dermatitis/eczema correct Correct. Itchy flexural dermatitis from infancy with a family history of atopy and a seasonal pattern. The diagnosis is not in doubt; the treatment is what has gone wrong.
5. Scabies Intense itch worse at night with burrows in the finger webs and wrists, and other household members affected. A 30 g tube of emollient lasting a month in widespread eczema points to it.

The point: Emollients are the foundation and are used in far larger quantities than people expect: around 250 to 500 g a week for a child with widespread eczema, continued even when the skin is clear. Topical steroid potency is matched to site and severity, with mild preparations on the face and flexures and potent ones reserved for thick lichenified skin on the trunk and limbs, never the face. Apply the steroid first or the emollient first with a gap of around 30 minutes, and use the fingertip unit to judge quantity. Eczema herpeticum is the emergency: rapidly worsening painful clustered punched-out erosions with fever, needing aciclovir and same-day assessment. Weeping, crusting and pustules suggest bacterial infection with Staphylococcus aureus.

Source: NICE CG57 — Atopic eczema in under 12s: diagnosis and management NICE · tier 1, national regulator or guidance

A 3 year old boy has itchy dry skin in the elbow and knee creases with excoriation, present since infancy and worse in winter. His mother has asthma. His mother uses a 30 g tube of emollient which lasts about a month, and applies hydrocortisone 1% to the flexures during flares. He sleeps poorly because of the itching. What is the SINGLE most appropriate initial investigation?

1. Patch testing For suspected allergic contact dermatitis, in a specialist clinic, and it is not the same as prick testing. A 30 g tube of emollient lasting a month in widespread eczema makes it appropriate.
2. Skin scrapings for fungal microscopy For an annular scaly lesion, particularly one that worsened on a topical steroid. A 30 g tube of emollient lasting a month in widespread eczema makes it worthwhile.
3. Viral swab for herpes simplex PCR For suspected eczema herpeticum, though treatment starts on clinical suspicion rather than on the result. A 30 g tube of emollient lasting a month in widespread eczema makes it confirmatory only.
4. Review the emollient quantity actually being used correct Correct. The single most useful question in a child whose eczema is not settling. Escalating the steroid before fixing this treats the wrong problem.
5. Bacterial swab of the weeping area For suspected bacterial superinfection, particularly where first-line treatment has failed. A 30 g tube of emollient lasting a month in widespread eczema indicates it.

The point: Emollients are the foundation and are used in far larger quantities than people expect: around 250 to 500 g a week for a child with widespread eczema, continued even when the skin is clear. Topical steroid potency is matched to site and severity, with mild preparations on the face and flexures and potent ones reserved for thick lichenified skin on the trunk and limbs, never the face. Apply the steroid first or the emollient first with a gap of around 30 minutes, and use the fingertip unit to judge quantity. Eczema herpeticum is the emergency: rapidly worsening painful clustered punched-out erosions with fever, needing aciclovir and same-day assessment. Weeping, crusting and pustules suggest bacterial infection with Staphylococcus aureus.

Source: NICE CG57 — Atopic eczema in under 12s: diagnosis and management NICE · tier 1, national regulator or guidance

A 3 year old boy has itchy dry skin in the elbow and knee creases with excoriation, present since infancy and worse in winter. His mother has asthma. His mother uses a 30 g tube of emollient which lasts about a month, and applies hydrocortisone 1% to the flexures during flares. He sleeps poorly because of the itching. What is the SINGLE most appropriate immediate management?

1. Topical calcineurin inhibitor Tacrolimus or pimecrolimus as a steroid-sparing option for the face and for frequently relapsing sites. A 30 g tube of emollient lasting a month in widespread eczema makes it useful.
2. Generous emollients, 250 to 500 g a week, continued when clear correct Correct. He is receiving roughly a twentieth of what he needs. Emollient in adequate quantity reduces both flares and the amount of steroid required.
3. Potent topical corticosteroid for the trunk and limbs For thick or lichenified eczema on the body, in short bursts, and never applied to the face. A 30 g tube of emollient lasting a month in widespread eczema makes it appropriate.
4. Topical antifungal, not a steroid For tinea, where a steroid suppresses the inflammation and lets the fungus spread. A 30 g tube of emollient lasting a month in widespread eczema makes it the correction.
5. Oral aciclovir and same-day dermatology assessment For eczema herpeticum. Around the eyes it is an ophthalmological emergency as well. A 30 g tube of emollient lasting a month in widespread eczema demands it.

The point: Emollients are the foundation and are used in far larger quantities than people expect: around 250 to 500 g a week for a child with widespread eczema, continued even when the skin is clear. Topical steroid potency is matched to site and severity, with mild preparations on the face and flexures and potent ones reserved for thick lichenified skin on the trunk and limbs, never the face. Apply the steroid first or the emollient first with a gap of around 30 minutes, and use the fingertip unit to judge quantity. Eczema herpeticum is the emergency: rapidly worsening painful clustered punched-out erosions with fever, needing aciclovir and same-day assessment. Weeping, crusting and pustules suggest bacterial infection with Staphylococcus aureus.

Source: NICE CG57 — Atopic eczema in under 12s: diagnosis and management NICE · tier 1, national regulator or guidance