Blistering Skin Disorders

Question 1

What is the cause of bullous pemphigoid?

Answer 1

Autoimmune reaction targeting hemidesmosomes, causing subepidermal blisters

=Hemidesmosomes anchor the epidermis to the dermis. When autoantibodies attack them (bullous pemphigoid), the epidermis lifts, forming subepidermal blisters (tense, sturdy blisters)

Question 2

Which age group is typically affected by bullous pemphigoid?

Answer 2

Elderly patients, usually >60 years old

Question 3

What type of hypersensitivity reaction is bullous pemphigoid?

Answer 3

Type II hypersensitivity
– IgG autoantibodies attack hemidesmosomes

Question 4

What are the early symptoms of bullous pemphigoid?

Answer 4

(1) Pruritus (itching)
(2) Well-demarcated erythematous plaques
(3) Before blisters appear

Question 5

How do the blisters in bullous pemphigoid present?

Answer 5

(1) Large
(2) Tense
(3) Extremely itchy blisters on normal or erythematous skin
(4) Usually in flexural areas

Question 6

Does bullous pemphigoid involve mucosal surfaces?

Answer 6

No, mucosal involvement is absent (unlike pemphigus vulgaris)

Question 7

What is the Nikolsky sign in bullous pemphigoid?

Answer 7

Negative – skin does not slough off when rubbed

Question 8

What does immunofluorescence show in bullous pemphigoid?

Answer 8

Linear IgG and complement deposits along the basement membrane

Question 9

What does histology show in bullous pemphigoid?

Answer 9

Subepidermal blisters with eosinophil-rich infiltrates

Question 10

What is the first-line treatment for localized bullous pemphigoid?

Answer 10

High-potency topical steroids

Question 11

What is the first-line treatment for systemic bullous pemphigoid?

Answer 11

Oral steroids ± tetracycline antibiotics ± antihistamines

Question 12

Why are tetracyclines used in bullous pemphigoid?

Answer 12

They act as steroid-sparing agents to reduce the need for high-dose steroids

Question 13

What is the next step if steroids do not control the disease?

Answer 13

Immunosuppression with azathioprine or methotrexate

Question 14

What is pemphigus vulgaris?

Answer 14

A rare autoimmune bullous disease causing fragile intra-epidermal blisters and mucosal ulcers

= Fragile blisters within the epidermis (intra-epidermal) form because desmosomes are attacked (pemphigus vulgaris), leading to easily ruptured blisters and painful mouth ulcers

Question 15

What is the most common subtype of the pemphigus group?

Answer 15

Pemphigus vulgaris (accounts for 80% of cases)

Question 16

What is the age group commonly affected by pemphigus vulgaris?

Answer 16

Middle-aged adults (40-60 years old)

Question 17

What type of hypersensitivity reaction is pemphigus vulgaris?

Answer 17

Type II hypersensitivity
– IgG4 autoantibodies target desmosomal proteins, causing acantholysis

Question 18

What is acantholysis?

Answer 18

Loss of keratinocyte adhesion due to destruction of desmosomes, leading to intra-epidermal blisters

Question 19

What are the main symptoms of pemphigus vulgaris?

Answer 19

1. Painful, fragile fluid-filled blisters
2. Blisters rupture to form shallow erosions
3. Commonly affects scalp, face, axillae, groin, trunk
4. Oral mucosa involvement – can be severe and life-threatening

Question 19

What is the Nikolsky sign in pemphigus vulgaris?

Answer 19

Positive – blisters extend when gentle lateral pressure is applied

Question 20

Does pemphigus vulgaris involve mucosal surfaces?

Answer 20

Yes, it commonly affects the oral mucosa and can involve the respiratory tract

Question 21

What does immunofluorescence show in pemphigus vulgaris?

Answer 21

“Chicken wire” pattern of IgG deposition within the epidermis

Question 22

What does histology show in pemphigus vulgaris?

Answer 22

Intra-epidermal blisters with inflammatory cells in the dermis

Question 23

What is the first-line treatment for localised pemphigus vulgaris?

Answer 23

Topical steroids + topical anesthetics for pain relief

Question 24

What is the first-line treatment for systemic pemphigus vulgaris?

Answer 24

1. High-dose oral steroids 2. Immunosuppressants (eg, azathioprine, mycophenolate) 3. Rituximab (if refractory to treatment)

Question 25

In which layer of the skin is the blister in bullous pemphigoid formed?

Answer 25

Between the dermis and epidermis

Question 25

Which two antigens are associated with bullous pemphigoid?

Answer 25

BP 1 and BP 2

Question 26

How is bullous pemphigoid typically managed?

Answer 26

Systemic steroid therapy for at least 2 years

Question 27

A 32-year-old woman attends the GP with a blistering skin condition. A biopsy was taken and immunofluorescence shows IgG deposition between cells in the epidermis. What is the most likely diagnosis?

Answer 27

Pemphigus vulgaris

Question 28

A 78-year-old man presents to the GP with a rash. He first noticed the rash 3 days ago and he explains that it is very itchy. On examination he has large tense bullae across his chest and back. Surrounding skin is erythematous. His mouth seems unaffected. Applying a pencil rubber onto his skin and twisting the pencil does not result in desquamation. What is the most likely investigation finding? and what is this disease describing?

Answer 28

Linear pattern of immunofluorescence along the basement membrane = bullous pemphigoid

Question 29

An 81-year-old man comes to A&E as he is very worried about a rash he has on his upper arms. He tells you that he originally had a hive-like rash which has now become blistered and very itchy. He tells you he has not had any change in medications or diet for at least 6 months. On examination, there is a red blistered rash on the patient's arms. The blisters are large and tense, and excoriations are surrounding them. Given the history and examination findings, what is the most likely diagnosis? and why do you think this?

Answer 29

Bullous pemphigoid = Bullous pemphiogoid is a blistering disorder that usually affects individuals over 60. It has a prodromal phase that involves inflammation of the affected skin, making it very itchy

Question 30

The presence of anti-BP180 and anti-BP230 antibodies is characteristic of what?

Answer 30

bullous pemphigoid

Question 31

Immunofluorescence shows a fish-net/chicken-wire pattern of staining within the epidermis. What disease is this describing?

Answer 31

Pemphigus Vulgaris

Question 32

Linear pattern of immunofluorescence along the basement membrane. What disease is this describing?

Answer 32

Bullous Pemphigoid

Question 33

A negative Nikolsky's sign is suggestive of what disease?

Answer 33

Bullous Pemphigoid

Question 34

A 56-year-old female presents with a blistering skin condition to the Dermatologist. Following examination, the Dermatologist suspects the condition could be Pemphigus Vulgaris. Which features would be consistent with a diagnosis of Pemphigus Vulgaris?

Answer 34

1. Positive Nikolsky sign (blisters extend with lateral pressure) 2. Painful, fragile blisters that rupture easily 3. Oral mucosal involvement (common) 4. Intra-epidermal blisters on histology 5. "Chicken wire" IgG deposition on immunofluorescence

Question 35

A 32-year-old woman attends the GP with a blistering skin condition. A biopsy was taken and immunofluorescence shows IgG deposition between cells in the epidermis What is the most likely diagnosis?

Answer 35

Pemphigus vulgaris

Question 36

A 60-year-old female presents with multiple painful erosions across her body. Her mouth is also sore. She tells you that there were some blistered areas before but these popped rapidly. A biopsy shows positive direct immunofluorescence for IgG within the epidermis in a fishnet pattern. What is the name of the target antigen?

Answer 36

Desmoglein-1

Question 36

A 57-year-old man presents to the Emergency Department with painful lesions in his mouth. On examination, he has flaccid bullae on the oral mucosa. The bullae rupture easily. Given the likely diagnosis, antibodies against which entity are likely to be present?

Answer 36

Desmosomes

Question 37

What autoimmune condition is strongly associated with Dermatitis Herpetiformis?

Answer 37

Coeliac disease (90% have gluten-sensitive enteropathy)

Question 38

What genetic marker is linked to Dermatitis Herpetiformis?

Answer 38

HLA-DQ2 haplotype

Question 39

What is the pathophysiology of Dermatitis Herpetiformis?

Answer 39

Gliadin (a gluten protein) triggers an immune response, leading to IgA antibodies against tissue transglutaminase (TTG). These antibodies deposit in the dermal papillae, causing inflammation and subepidermal blisters (dermatitis herpetiformis)

Question 40

What are the characteristic skin findings in Dermatitis Herpetiformis?

Answer 40

(1) Intensely itchy (2) Symmetrical vesicles on an erythematous base (3) Often excoriated

Question 41

Where are the lesions of Dermatitis Herpetiformis typically found?

Answer 41

Extensor surfaces—elbows, knees, and buttocks

Question 42

What serological tests are positive in Dermatitis Herpetiformis?

Answer 42

Anti-TTG and IgA antibodies

Question 43

What biopsy findings confirm Dermatitis Herpetiformis?

Answer 43

1. Granular IgA deposits in dermal papillae (immunofluorescence) 2. Subepidermal blisters with papillary micro-abscesses (histology)

Question 44

What is the mainstay of treatment for Dermatitis Herpetiformis?

Answer 44

Gluten-free diet ± dapsone

Question 45

What serious complication is associated with Dermatitis Herpetiformis?

Answer 45

Increased risk of small bowel lymphoma

Question 46

What is the typical age of onset for dermatitis herpetiformis?

Answer 46

15-40 years

Question 47

A 34-year-old woman presents to her GP with abdominal pain and diarrhoea. She has said that is has been going on for a long time but has become especially bad over the last few months. She also states that she has noticed and intensely itchy rash on her knees and back that has become much worse over the last few weeks. She states that she has had no change in her diet and takes no regular medications. On examination, she has mild generalised tenderness of her abdomen and her conjunctiva appear pale. The rash on her knees is a pink papulovesicular rash. The blisters vary in size. Her skin also appears very excoriated and sore. Given the history and examination, what is the most likely diagnosis?

Answer 47

Dermatitis herpetiformis

Question 48

What is the first line management option for Dermatitis Herpetiformis?

Answer 48

Dapsone

Question 49

If blisters have burst what does this rule out?

Answer 49

Bullous pemphigoid

Question 50

A 25-year-old man presents with a pruritic skin rash. This has been present for the past few weeks and has responded poorly to an emollient cream. The pruritus is described as 'intense' and has resulted in him having trouble sleeping. On inspecting the skin you notice a combination of papules and vesicles on his buttocks and the extensor aspect of the knees and elbows. What is the most likely diagnosis?

Answer 50

Dermatitis herpetiformis = Dermatitis herpetiformis doesn't improve with moisturisers

Question 51

An 84-year-old woman presents to her GP with a complaint of a newly developed itchy rash on her feet, which has appeared over the past week. She has a past medical history of coeliac disease. Upon examination, there is a patchy, raised, violaceous rash on the posterior and medial aspects of both ankles. There are several fine white lines traversing the surface of the rash and evidence of excoriations. What is the most likely diagnosis?

Answer 51

Lichen planus

Question 52

A 36-year-old woman presents to the clinic with a 4-month history of intermittent bloating and loose stools. She has never passed any blood but has lost a few kilograms in weight. Over the past week, she has noticed some itchy, vesicular rashes on her elbows that won't seem to go away. You send off some routine blood tests which come back as normal except for one positive result. Anti-TTG = Positive What is the dermatological condition that she describes?

Answer 52

Dermatitis herpetiformis

Question 53

"A 22-year-old woman is troubled by intensely itchy crops of blisters on her arms and legs. On examination she is malnourished and she has papulovesicular eruptions over her elbows and knees" What is this describing?

Answer 53

Dermatitis herpetiformis