Psoriasis and Dermatitis

Question 1

What is the most prevalent autoimmune disease?

Answer 1

Psoriasis vulgaris

Question 2

What is the most important susceptibility locus and where is it found?

Answer 2

PSORS1 (found in 50% of cases). Found in MHC region of chromosome 6

Question 3

What is an example of another psoriasis susceptibility locus?

Answer 3

RUNX1, found on chromosome 17q25. A binding site variant, encoding for a gene involved in the development of blood cells

Question 4

What are the hallmarks of psoriasis?

Answer 4

Hyper-profileration and abnormal differentiation of epidermal keratinocytes
Infiltration of T lymphocytes
Endothelial vascular changes in dermal layer like angiogenesis, dilatation etc

Question 5

What leads to impaired barrier function and increased antigen entry?

Answer 5

Exposure to microbial or mechanical injury damage together with keratinocyte injury

Question 6

What do psoriasis therapeutic drugs aim to do?

Answer 6

Induce apoptosis of T cells, block T cell migration and adhesion, and antagonise effector cytokines

Question 7

What do the terms dermatitis and eczema imply?

Answer 7

Dermatitis implies an acute inflammation of skin

Eczema implies a chronic inflammation of skin

Question 8

What is atopic dermatitis?

Answer 8

An allergic disease with a hereditary component

Question 9

What is contact dermatitis?

Answer 9

2 types: allergic and irritant. Some substances act as both

Question 10

What is xerotic eczema?

Answer 10

Where dry skin becomes so serious it turns into eczema, very common among older population

Question 11

What is suborrhoeic dermatitis?

Answer 11

Closely related to dandruff

Question 12

What are some causes of atopic eczema?

Answer 12

Genetics (exact genes unknown), hormonal changes in women, stress, exercise, irritants

Question 13

What therapeutic approaches are there for eczema?

Answer 13

Emollients to soften skin
Topical corticosteriods for severe symptoms
Antibiotics for infected eczema
Topical immunosuppressants
Self care include scratching, avoiding triggers, diet

Question 14

What is the first stage of psoriasis pathogenesis?

Answer 14

Exposure to microbial or mechanical damage injury together with keratinocyte injury lead to impaired barrier function along with antigen entry

Question 15

What is the second stage of psoriasis pathogenesis?

Answer 15

These events lead to increased production of AMP, TNF-alpha, IL-6, IL-1ß to recruit APCs

Question 16

What is the third stage of psoriasis pathogenesis?

Answer 16

Interaction of APCs and T cells lead to T cell activation which further involves the interactions between receptors and ligand of APCs and T cell receptors

Question 17

What is the fourth stage of psoriasis pathogenesis?

Answer 17

This leads to the activation of Th1 cells (mediated by TNF-alpha, IFN-gamma) and Th17 cells (mediated by IL-23)

Question 18

What is the fifth stage of psoriasis pathogenesis?

Answer 18

Liberation of IL-17 and IL-22 (by Th17 cells) along with TNF-alpha and IFN-gamma (by Th1 cells) further perpetuates keratinocyte injury, creating a vicious feedback cycle