6- Dermatology (Blistering and Pigment disorders) Flashcards
Blistering disorders
Split into
- Immunobullous disease
- Blistering skin infections
Immunobullous disease
o Bullous pemphigoids
o Pemphigus vulgaris
Blistering skin infections
o Herpes simplex
o Porphyria cutanea tarda
Bullous pemphigoid
Background
- Autoimmune
- Blistering, itchy skin disorder usually affect elderly
Bullous pemphigoid pathophysiology
Pathophysiology
- Autoantibodies against antigens between the epidermis and dermis causing a sub-epidermal split in the skin
Bullous pemphigoid presentation
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
management of bullous pemphigoid
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
Pemphigus vulgaris
Background
- Autoimmune
- Blistering skin disorder which usually affects middle-aged people
Pathophysiology Pemphigus vulgaris
- Autoantibodies against antigens with the epidermis causing intra-epidermal split in the skin
presentation pemphigus vulgaris
- Flaccid easily ruptured blisters forming erosions and crusts
- Lesions are painful
- Usually affects mucosal area
management of pemphigus vulgaris
General measures
- Wound dressings
- Monitor for infection
- Good oral care
Oral therapies
- High dose oral steroids
- Immunosuppressives e.g. methotrexate, azathioprine, cyclophosphamide, mycophenolate mofetil
Bullous pemphigois vs pemphigus vulgaris
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
Pigment disorders
- Hypopigmentation -reduced
- Depigmentation- complete loss
- Hyperpigmentation – increased
Common conditions
- Vitiligo
- Melasma
Vitiligo
Background
- Acquired depigmenting disorder
- Complete loss of pigment cells -> melanocytes
- Presents at any age
Pathophysiology of vitiligo
- Autoimmune disorder where innate immune system causes loss of melancoytes, leading to loss of pigment
presentation of vitiligo
- 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
management of vitiligo
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
Melasma
Background
- Acquired chronic skin disorder
- Increased pigmentation in the skin -> hyperpigmentation
melasma risk factors and causes
- Genetic predisposition
- Triggers
o Sun exposure
o Hormonal changes e.g. pregnancy and contraceptives
Pathophysiology of melasma
- Overproduction of melanin by melanocytes
Presentation of melasma
- 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
