Inflammatory dermatoses

Question 1

What are the 3 layers of the skin?

Answer 1

Epidermis
Dermis
Hypodermis

Question 2

What is dermatitis also known as?

Answer 2

Eczema

Question 3

What are the different types of eczema?

Answer 3

Atopic
Seborrhoeic
Discoid
Allergic contact

Question 4

What is the definition of atopy?

Answer 4

Tendency to develop hypersensitivity

Question 5

What is atopic eczema?

Answer 5

Very common itchy skin condition

Question 6

What is the onset of atopic eczema like?

Answer 6

It is often within first 6 months of life. Many children grow out of it but a proportion doesn’t

Question 7

What is the biology of eczema?

Answer 7

Defective barrier function of the skin leading to dry skin

Question 8

What is mutated in 10% of eczema cases?

Answer 8

Filagrin gene

Question 9

What is filagrin?

Answer 9

Epidermal protein important in maintaining barrier function of the skin

Question 10

What does defective barrier function in eczema allow?

Answer 10

Penetration of irritants, allergens (e.g. house dust mite particles) and pathogens e.g. staph aureus. Inflammation of the skin then occurs

Question 11

What is seborrhoeic eczema?

Answer 11

Very common type of eczema affecting babies and adults, often not itchy

Question 12

What is the pathology of seborrhoeic eczema?

Answer 12

There is overgrowth of malassezia species of yeast on the skin with associated skin inflammation.

Question 13

What is distinctive in seborrhoeic eczema?

Answer 13

The rash has a distinctive distribution including nasolabial folds, eyebrows, scalp, central chest and sometimes axillae and groins

Question 14

What is psoriasis?

Answer 14

Another common inflammatory dermatosis

Question 15

When does psoriasis usually start?

Answer 15

Teens or 40s/50s

Question 16

What are the different types of psoriasis?

Answer 16

Chronic plaque
Guttate
Palmoplantar pustulosis
Generalised pustular psoriasis

Question 17

What percentage of patients with cutaneous disease are affected by psoriatic arthritis?

Answer 17

Approximately 30%

Question 18

What are the underlying cause of psoriasis?

Answer 18

Genetic susceptibility and environmental triggers- many genes are implicated including PSOR1

Question 19

What is the pathophysiology of psoriasis?

Answer 19

Immune process occurs where T lymphocytes move out of blood vessels into the dermis and initiate the release of cytokines e.g. tumour necrosis factor alpha. The epidermis becomes thickened and produces more keratinocytes than normal, neutrophils infiltrate the epidermis and lymphocytes infiltrate the dermis

Question 20

What triggers for psoriasis are there?

Answer 20

Infections
Drugs
Stress

Question 21

Who is mainly infected by acne?

Answer 21

A very common condition which mainly affects teenagers and young adults

Question 22

What is the biology of acne?

Answer 22

It is disease of the pilosebaceous unit of the skin

Question 23

What is the pathogenesis of acne?

Answer 23

It is multifactorial and includes:
Hyperkeratinisation of the epidermis in the infundibulum of the hair follicles
Accumulation of dead keratinocytes in lumen of the hair follicle
Increased sebum production stimulated by androgens
Proliferation of propionibacterium acnes within the pilosebaceous unit
Rupture of the inflamed pilosebaceous unit with further inflammation of the surrounding skin

Question 24

What are the key clinical features of acne?

Answer 24

Open and closed comedones
Papules
Pustules
Nodules
Scars
on face, chest and back

Question 25

What is bullous pemphigoid?

Answer 25

An autoimmune bullous inflammatory condition most common in the elderly

Question 26

What are the clinical features of bullous pemphigoid?

Answer 26

Intense pruritus followed by development of tense blisters on an erythematous background of skin or mucous membranes

Question 27

What is the biology of bullous pemphigoid?

Answer 27

IgG antibodies to basement membrane antigens BP180 or BP230 result in cleavage of skin at the demo-epidermal junction leading to sub-epidermal blisters

Question 28

What is pemphigus vulgaris?

Answer 28

An uncommon autoimmune bullous inflammatory disease which usually affects middle aged individuals

Question 29

What do the clinical features of pemphigus vulgaris include?

Answer 29

Flaccid blisters which easily break leaving erosions and crusted lesions

Question 30

What is the biology of pemphigus vulgaris?

Answer 30

IgG autoantibodies to epidermal cell surface proteins desmoglzins 1 and 3 lead to loss of cell-cell adhesion within the epidermis causing flaccid blisters in the skin or mucous membranes