6- Dermatology (Blistering and Pigment disorders)

Question 1

Blistering disorders
Split into

Answer 1

• Immunobullous disease
• Blistering skin infections

Question 2

Immunobullous disease

Answer 2

o Bullous pemphigoids
o Pemphigus vulgaris

Question 3

Blistering skin infections

Answer 3

o Herpes simplex
o Porphyria cutanea tarda

Question 4

Bullous pemphigoid
Background

Answer 4

• Autoimmune
• Blistering, itchy skin disorder usually affect elderly

Question 5

Bullous pemphigoid pathophysiology

Answer 5

Pathophysiology
- Autoantibodies against antigens between the epidermis and dermis causing a sub-epidermal split in the skin

Question 6

Bullous pemphigoid presentation

Answer 6

It usually starts with an itchy, raised rash. As the condition develops, large blisters can form on the skin. It may last a few years and sometimes causes serious problems, but treatment can help manage the condition in most cases.

• Tense, fluid-filled blisters on an erythematous base
• Lesions are often itchy
• Preceded by non-specific itchy rash
• Does not affect mucosal areas
• Trunk and limbs

Question 7

management of bullous pemphigoid

Answer 7

General
- Wound dressings
- Monitor for infection

Topical for localised disease
- Topical steroid

Oral for widespread disease
* Oral steroids
* Tetracycline and nicotinamide
* Immunosuppressive agents
* Azathioprine
* Mycophenolate mofetil
* Methotrexate

Question 8

Pemphigus vulgaris
Background

Answer 8

• Autoimmune
• Blistering skin disorder which usually affects middle-aged people

Question 9

Pathophysiology Pemphigus vulgaris

Answer 9

• Autoantibodies against antigens with the epidermis causing intra-epidermal split in the skin

Question 10

presentation pemphigus vulgaris

Answer 10

• Flaccid easily ruptured blisters forming erosions and crusts
• Lesions are painful
• Usually affects mucosal area

Question 11

management of pemphigus vulgaris

Answer 11

General measures
- Wound dressings
- Monitor for infection
- Good oral care

Oral therapies
- High dose oral steroids
- Immunosuppressives e.g. methotrexate, azathioprine, cyclophosphamide, mycophenolate mofetil

Question 12

Bullous pemphigois vs pemphigus vulgaris

Answer 12

Types of blisters

Pemphigus is characterized by shallow ulcers or fragile blisters that break open quickly. Pemphigoid presents with stronger or “tense” blisters that don’t open easily.

Location: Initial site also varies; pemphigus vulgaris generally starts in the oral mucosa whereas bullous pemphigoid affects the extremities at onset. From onset, pemphigus vulgaris will spread widely to the face, scalp, flexural surfaces, and trunk; bullous pemphigoid moves inward to the flexural surfaces and trunk.23

Question 13

Pigment disorders

Answer 13

• Hypopigmentation -reduced
• Depigmentation- complete loss
• Hyperpigmentation – increased

Common conditions
- Vitiligo
- Melasma

Question 14

Vitiligo
Background

Answer 14

• Acquired depigmenting disorder
• Complete loss of pigment cells -> melanocytes
• Presents at any age

Question 15

Pathophysiology of vitiligo

Answer 15

• Autoimmune disorder where innate immune system causes loss of melancoytes, leading to loss of pigment

Question 16

presentation of vitiligo

Answer 16

• Single patch or multiple patches of depigmentation
• Often symmetrical
• Common sites are exposed areas
  o Face
  o Hands
  o Feet

Others
o Genitalia
o Body fold
- Favours sites of injury e.g. Koebner phenomenon

Question 17

management of vitiligo

Answer 17

Management
- Minimise skin injury e.g. cut, graze, sunburn -> trigger for new patch
- Topical treatments
o Steroids
o Calcineurin inhibitors e.g. tacrolimus
- Phototherapy e.g. UVB therapy
- Oral immunosuppressants e.g. methotrexate, ciclosporin and mycophenolate mofetil

Question 18

Melasma

Background

Answer 18

• Acquired chronic skin disorder
• Increased pigmentation in the skin -> hyperpigmentation

Question 19

melasma risk factors and causes

Answer 19

• Genetic predisposition
• Triggers
  o Sun exposure
  o Hormonal changes e.g. pregnancy and contraceptives

Question 20

Pathophysiology of melasma

Answer 20

• Overproduction of melanin by melanocytes

Question 21

Presentation of melasma

Answer 21

• Brown macule (freckle-like spots) or larger patches with an irregular border
• Symmetrical distribution
• Common sites
  o Forehead
  o Cutaneous upper lips
  o Cheeks
• Others
  o Neck
  o Shoulders
  o Upper arms