Immunology and the skin

Question 1

skin structure

Answer 1

3 layers
- epidermis: mainly keratinocytes with melanocytes at the basal layer, give skin colour
- dermis: connective tissue, blood vessels etc
- fat layer/panniculus
dermoepidermal junction has many proteins which stick the two layers together

Question 2

Bulls pemphigoid BP

Answer 2

most common immunobullous disease
Usually older patients, 70+
Complain of itchy rash then develop blisters
Association of cerebrovascular injury to onset
BP is autoimmune reaction against two proteins in the semi desmosomes, which help stick the epidermis to the dermis, antibodies to these proteins lose adhesion causing epidermis to split from dermis.
Immune reaction against the neural isoform can result in a cross over reaction in the skin.
tense blisters

Question 3

Pemphigus vulgaris PV

Answer 3

Rare disorder presenting in younger patients
Depending on subtypes may also involve the mucous membranes as well as the skin
Due to an autoimmune reaction against the desmoglein proteins in desmosomes that perform keratinocyte adhesion
shallow blisters and skin erosions because immune attack within epidermis

Question 4

Direct immunofloursence

Answer 4

to decide where the immune attack is occurring
Antihuman antibodies with a fluorescing tag directed against the antibodies causing BP and PV, therefore staining at the demo-epidermal junction in BP and epidermis in PV

Question 5

Patch testing

Answer 5

uses purified antigen to provoke dermatitis on the back

patient can avoid antigen if identified

Question 6

Atopic eczema

Answer 6

common condition in NZ children usually improves with age, most resolved by adulthood

Question 7

How can patients be genetically predisposed to having atopic adult eczema?

Answer 7

genetic mutation for filaggrin protein which forms a natural moisturiser in the skin so this natural moisturiser effect is diminished and the barrier function of skin impaired
Antigens can penetrate the skin more easily leading to immunological reactions
patients with atopic eczema have a higher prevalence of allergy than those who don’t

Question 8

what layer of the skin does dermatitis affect?

Answer 8

The granular layer on top of the epidermis

Question 9

Examples of occupations that have a higher risk of allergy contact dermatitis

Answer 9

hairdressing

Question 10

Irritant contact dermatitis?

Answer 10

due to cumulative wear and tear of the hands and not due to allergy

Question 11

How to determine whether antigens are important in dermatitis?

Answer 11

patch testing

Question 12

Reasons why patients might be immunosuppressed? give examples

Answer 12

Due to treatments of disease e.g. patients with bulls pemphigoid need prednisone and azathioprine to control the blistering otherwise they’ll die from skin failure
Due to the effects of disease, congenital or acquired immunodeficiency states: e.g. HIV
Due to the effects of drugs required for organ transplantation e.g. renal transplants

Question 13

The two possible pathologies resulting from immunosuppression of the skin?

Answer 13

Infection of neoplasia

Question 14

Common forms of skin cancer in NZ based on immune state?

Answer 14

Normal: basal cell carcinoma
Compromised: squamous cell carcinoma

Question 15

Examples of immune skin diseases needing better solutions

Answer 15

psoriasis, vitiligo, alopecia areata