1. Dermatology and Infectious Diseases
Disorders of Keratinisation
Dermatitis
Blistering Disorders
Immunology

2. Disorders of Keratinisation
Overview
Psoriasis
Icthyosis

3. Objectives
Disorders of Keratinisation

4. Disorders of Keratinization
Terminal differentiation of epithelia
epithelial proteins (Keratin)
Glycoproteins (Cell Envelope)
intercellular lipids

5. Disorders of Keratinization
Cause changes in the skin
Dry, Scaly, Thickened, Flaky
Blistering
Cause changes in Mucous membranes, Nails and Hair

6. Disorders of Keratinization
Change in Type of Keratin Made

7. Disorders of Keratinisation

8. Disorders of Keratinisation

9. Disorders of Keratinization
Psoriasis
Icthyosis

10. Disorders of Keratinization Psoriasis
Chronic , relapsing and remitting skin disease.
May appear at any age
may affect any part of the skin
Common Locations:
Extensor surfaces Knees and Elbows

11. Disorders of Keratinization Psoriasis
Characterised by hyperproliferation of skin and inflammation

12. Disorders of Keratinization Psoriasis
Etiology
Inherited
Abnormality of Ca++ metabolism
Genetic Predisposition
HLA Cw6
HLA DR7
HLA B27 (Pustular)

13. Disorders of Keratinization Psoriasis
Etiology
Environmental Factors
Stress, Smoking and Alcohol
Systemic Drugs
Infection
Immunological Factors

14. Psoriasis
Gawkrodger, D.J. (1992) Dermatology. Edinburgh: Churchill Livingston. (1992)

15. Disorders of Keratinization Psoriasis
Abnormalities in Psoriatic Skin
 transit time through epidermis
mitotic activity
rate of DNA synthesis
high levels of Ca++ binding protein calmodulin
Presence of keratin 6 & 16 in epidermis
These five are must knows

16. Disorders of Keratinization Psoriasis
Abnormalities in Psoriatic Skin
 levels of phospholipase A2 activity
levels of polyamine synthesis
levels of plasminogen activator
cGMP levels leading to a high ratio cGMP/cAMP
These 4 are included for the sake of completeness

17. Disorders of Keratinization Psoriasis
Pathology
Stratum Corneum
contains nuclei
Stratum granulosum
doesn’t exist
Stratum Spinosum
expanded
bulbous downward projections
mitosis

18. Disorders of Keratinization Psoriasis
Pathology contd.
Papillary Dermis
Papillae thickened
large dilated thin walled blood vessels
Dermis/Epidermis
infiltrated with leukocytes
in Stratum corneum these clump together to form Spongiform pustules (aka Munro microabscesses)

19. Psoriasis
Gawkrodger, D.J. (1992) Dermatology. Edinburgh: Churchill Livingston. (1992)

20. Psoriasis Koebner Phenomenon
Gawkrodger, D.J. (1992) Dermatology. Edinburgh: Churchill Livingston. (1992)

21. Required Reading
Gawkrodger, D.J. (1992) Dermatology. Edinburgh: Churchill Livingston. (1992)
Psoriasis

22. Disorders of Keratinisation Icthyoses
A variety of hereditary keratinisation disorders
visible scales on the skin
Forms include
autosomal dominant
x-linked
associated with multisystem changes

23. Disorders of Keratinisation Icthyoses
May vary from very mild to very severe
The keratinisation process which is changed varies from condition to condition

24. Icthyosis
Gawkrodger, D.J. (1992) Dermatology. Edinburgh: Churchill Livingston. (1992)

25. Required Reading
Gawkrodger, D.J. (1992) Dermatology. Edinburgh: Churchill Livingston. on Keratinization and Blistering Syndromes

26. Dermatitis/eczema dermatitis = eczema
non-infective inflammation of the skin
Greek for ‘to boil over’
reaction to various stimuli
some known, some unknown

27. Dermatitis Classification
current classification unsatisfactory/inconsistent
distinctions are often difficult to determine
endogenous (internal factors)
exogenous (external factors)
acute
chronic

28. Dermatitis Acute
acute eczema leads to epidermal oedema (spongiosis), with separation of keratinocytes
leads to epidermal vesicles
dermal vessels become dilated
inflammatory cells invade the dermis and epidermis

29. Dermatitis Chronic
chronic eczema leads to a thickening of the stratum spinosum (acanthosis) & stratum corneum (hyperkeratosis)
also get retention of nuclei by some corneocytes
rete ridges are lengthened
dermal vessels are dilated
inflammatory mononuclear cells infiltrate the skin

30. Dermatitis
Gawkrodger, D.J. (1992) Dermatology. Edinburgh: Churchill Livingston. (1992)

31. Dermatitis Types of dermatitis/eczema
contact dermatitis/eczema
contact with an irritant
atopic dermatitis/eczema
associated with a history of asthma, allergic rhinitis, conjunctivitis
seborrhoeic dermatitis/eczema
commonly affects the scalp and face

32. Dermatitis Types of dermatitis/eczema cont.
discoid (nummular) dermatitis/eczema
often presents as coin-shaped lesions on the limbs of middle aged or older people
venous stasis dermatitis/eczema
associated with venous disease
commonly involves the medial aspect of the ankle

33. Required Reading
Gawkrodger, D.J. (1992) Dermatology. Edinburgh: Churchill Livingston., D.J. (1992) Dermatology. Edinburgh: Churchill Livingston.
Chapters on Eczema

34. Bullous Disorders
blistering (bullous) disorders are often seen with skin disease
found with common skin conditions like acute contact dermatitis
Etiology-autoimmune mechanisms, inheredited errors in metabolism and mechanical trauma

35. Types of Bullous Disorders
Pemphigus
Pemphigoid
Epidermolysis bullosa
dermatitis herpetiformis
linear lgA disease
Fungi
Friction
Systemic lupus erythematosis (SLE)
Erythema multiforme
Stevens-Johnson syndrome
Bullous impetigo
Bullous diabeticorum

36. Bullous disorders
Blisters are classified according to their position in the epidermis.
SubCorneal :Stratum Corneum
Intraepidermal: Lower levels of the epidermis
Sub Epidermal: At the dermo-epidermal junction

37. Blistering Disorders

38. Friction Blisters direct mechanical trauma
Treatment: avoidance-look at footwear, protective taping and padding, 2 pairs of socks, lubrication.
sock design and reduction of blistering
Ref.-Herring and Ritchie in JAPMA 1990 and 1993.

39. Required Reading
Gawkrodger, D.J. (1992) Dermatology. Edinburgh: Churchill Livingston.
Read Chapter on Blistering Disorders and chapter on Keratinization and Blistering Syndromes

40. Hypersensitivity Reactions and the Skin
inappropriate or exaggerated response to the degree that tissue damage occurs.
4 Types
Type l -immediate
Type ll -antibody dependant cytotoxicity
Type lll-immune complex disease
Type lV-cell mediated or delayed