Dermatology for AMC MCQ

A 6 year old boy has a long history of an itchy rash in the creases of his elbows and knees, dry and thickened from scratching, that flares and settles. He has asthma and hay fever, and his mother had childhood eczema. There is no weeping, crusting or blistering. His sleep is disturbed by the itch. What is the most likely diagnosis?

1. Eczema herpeticum A painful eruption of small blisters that complicates eczema, an emergency. It does not fit a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection.
2. Scabies Intense itch with burrow marks and a family member with the same itch. But a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection does not point to it.
3. Atopic dermatitis/eczema correct Correct. A long-standing, itchy rash in the skin creases, with a personal and family history of allergy-type conditions, is atopic dermatitis.
4. Psoriasis Clearly-edged patches with silvery scale on the outer sides of the elbows and knees. That does not match a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection.
5. Cutaneous T-cell lymphoma A rash in an adult that will not clear and looks unusual. Here, a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection points elsewhere.

The point: Atopic dermatitis (eczema) is a long-term, itchy skin condition that comes and goes. It usually starts in childhood, often in someone with a personal or family history of allergy-type conditions (atopy). In babies it affects the face and the outer sides of the arms and legs. In older children and adults it affects the skin creases (flexures), such as the inside of the elbows and knees. The skin is dry, itchy and red, and heavy scratching thickens it over time (lichenification). The main treatment is moisturiser (emollient), used often and every day to protect the skin, even when it looks clear. Avoid soap. Steroid cream treats flares. Pick a strength that matches the area of skin and how bad the flare is. The common mistake is using a steroid that is too weak or stopping it too soon. Find and cut down triggers, such as heat, harsh products and, in some people, specific allergens. Watch for infection. A weeping, crusted patch needs antibiotics. Eczema herpeticum is an emergency. It is a widespread, painful eruption of small blisters with punched-out sores, caused by the cold sore virus (herpes simplex), and it needs the antiviral drug aciclovir. Severe or hard-to-control eczema is referred for light treatment (phototherapy) or drugs that work on the whole body (systemic therapy). Most children's eczema gets better as they grow up.

Source: Therapeutic Guidelines (Australia) — Dermatology: atopic dermatitis Therapeutic Guidelines (Australia) · tier 3, national formulary

A 6 year old boy has a long history of an itchy rash in the creases of his elbows and knees, dry and thickened from scratching, that flares and settles. He has asthma and hay fever, and his mother had childhood eczema. There is no weeping, crusting or blistering. His sleep is disturbed by the itch. What is the most appropriate initial investigation?

1. Swab of infected or non-healing lesions Take a swab where infection is suspected. It does not fit a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection.
2. Consider biopsy for an atypical persistent rash Take a skin sample when the diagnosis is not clear. That does not match a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection.
3. Recognition of eczema herpeticum Painful blisters that all look the same, with punched-out sores. But a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection does not point to it.
4. Clinical diagnosis from the pattern and atopic history correct Correct. The pattern of the rash and his allergy-type history are enough to diagnose it without tests.
5. Assessment of severity and impact How bad it is guides the next treatment step. Here, a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection points elsewhere.

The point: Atopic dermatitis (eczema) is a long-term, itchy skin condition that comes and goes. It usually starts in childhood, often in someone with a personal or family history of allergy-type conditions (atopy). In babies it affects the face and the outer sides of the arms and legs. In older children and adults it affects the skin creases (flexures), such as the inside of the elbows and knees. The skin is dry, itchy and red, and heavy scratching thickens it over time (lichenification). The main treatment is moisturiser (emollient), used often and every day to protect the skin, even when it looks clear. Avoid soap. Steroid cream treats flares. Pick a strength that matches the area of skin and how bad the flare is. The common mistake is using a steroid that is too weak or stopping it too soon. Find and cut down triggers, such as heat, harsh products and, in some people, specific allergens. Watch for infection. A weeping, crusted patch needs antibiotics. Eczema herpeticum is an emergency. It is a widespread, painful eruption of small blisters with punched-out sores, caused by the cold sore virus (herpes simplex), and it needs the antiviral drug aciclovir. Severe or hard-to-control eczema is referred for light treatment (phototherapy) or drugs that work on the whole body (systemic therapy). Most children's eczema gets better as they grow up.

Source: Therapeutic Guidelines (Australia) — Dermatology: atopic dermatitis Therapeutic Guidelines (Australia) · tier 3, national formulary

A 6 year old boy has a long history of an itchy rash in the creases of his elbows and knees, dry and thickened from scratching, that flares and settles. He has asthma and hay fever, and his mother had childhood eczema. There is no weeping, crusting or blistering. His sleep is disturbed by the itch. What is the most appropriate next step in management?

1. Aciclovir for eczema herpeticum Aciclovir is the emergency treatment for the herpes-virus infection. That does not match a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection.
2. Antibiotics for bacterial infection Antibiotics treat a weeping, crusted, infected patch of eczema. It does not fit a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection.
3. Liberal emollients as the cornerstone correct Correct. Frequent moisturiser is the base of treatment, protecting the skin barrier.
4. Trigger avoidance and soap substitution Cutting down triggers and using a soap-free wash reduces irritation. Here, a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection points elsewhere.
5. Referral for phototherapy or systemic therapy Send severe or hard-to-control eczema for light treatment or drugs that work on the whole body. But a long-standing, itchy rash in the skin creases with an allergy-type history and no sign of infection does not point to it.

The point: Atopic dermatitis (eczema) is a long-term, itchy skin condition that comes and goes. It usually starts in childhood, often in someone with a personal or family history of allergy-type conditions (atopy). In babies it affects the face and the outer sides of the arms and legs. In older children and adults it affects the skin creases (flexures), such as the inside of the elbows and knees. The skin is dry, itchy and red, and heavy scratching thickens it over time (lichenification). The main treatment is moisturiser (emollient), used often and every day to protect the skin, even when it looks clear. Avoid soap. Steroid cream treats flares. Pick a strength that matches the area of skin and how bad the flare is. The common mistake is using a steroid that is too weak or stopping it too soon. Find and cut down triggers, such as heat, harsh products and, in some people, specific allergens. Watch for infection. A weeping, crusted patch needs antibiotics. Eczema herpeticum is an emergency. It is a widespread, painful eruption of small blisters with punched-out sores, caused by the cold sore virus (herpes simplex), and it needs the antiviral drug aciclovir. Severe or hard-to-control eczema is referred for light treatment (phototherapy) or drugs that work on the whole body (systemic therapy). Most children's eczema gets better as they grow up.

Source: Therapeutic Guidelines (Australia) — Dermatology: atopic dermatitis Therapeutic Guidelines (Australia) · tier 3, national formulary