5: Inflammatory dermatoses Flashcards
Which layer of the skin is associated with its normal barrier function?
What is it made of?
It is mainly situaties in the stratum Corneum
It contains of
- Kerationocytes (differentiated as Corneocytes)
- and a “special glue”
- made up of lipids and filagrin
What is the main risk factor for development of eczema?
Defect Skin Barrier Function
- makes it easier for pathogens to enter the skin
Explain the pathophysiology of atopic eczema
- Defective barrier function of the skin allows
- extrinsic factors to enter the skin
- e.g. allergens
- irritangs (e.g. soaps)
- pathogens
- Leading to
-
Acute Eczema
- Activation of the immune system (CD4+ T cells and Th2 cells)
- Trigger B-cell to produce antibodies
- Mast cell degradation and inflammatory response (histamine release)
-
Chronic Eczema
- Activation of CD4+, Th1 and CD8+ T-cells (mediated via eosinophils)
Explain the relationship betwen hyperlinearity and eczema
It is a sign of sign of filagrin gene mutation –> sign of defect barrier function of the skin
–> people are more prone to eczema
What is the clinical presentation of actute atopic dermatitis?
Generally: ichy, red, inflammes plaques (exzema)
Site changes with age
- Children:
- extensor sites of limbs (elbow/knee)
- face
- Adults
- neck
- flexor (cubital and polpiteal fossas)
- bakc of hands
What is the clinical presentation of chronic atopic dermatitis?
lichenification (Thickening of the skin with accentuated skin markings) but associated with less redness
- poorly defined borders
What is Erythidema?
Severe eczema over whole body
(patients are unwell and miht require hispilalisation)
Explain the relationship between eczema and infections
Because of defect skin barrier:
- increased risk of infection
- e.g. staph A
- Herpes simplex wich might lead to eczema herpeticum
What is atopic eczema?
It is an actopic disease –> hypersensitivity in skin
What is Seborrhoeic Eczema?
Same as dandruffs on other parts of body (often in face)
- increased yeast growth on skin
What is Allergic contact dermatitis?
sensitisation to specific allergens e.g. cosmetics, hair dye, henna tattoos (PPD), Nickel etc.
–> When contact: dermatitis and inflammation
What is Discoid eczema?
- related to dryness of skin with
- often in elderly that whash themselves a lot
- round/coin shaped eczemas
What is psoriasisi?
What is its clinical presenation?
It is a disease that causes well defined, several larger patches which have cales and plaques on them
often symmetrical on
- scalp
- trunk
- armpit
- elbows
*
What are the pathophysiological and histological changes in psoriasis
Hyperproliferation of keratinocytes leading to
- hyperkeratosis –> too much formation of keratin
- Parakreatosis –> no loss of cell nuclei at the top of epidermis
- Acanthosis –> thickened epidermis
Also
Inflammation
Dilated blood vessels –> redness
What is Psoriasis Soles?
Psoriasis at the soles of the feet
What are the changes in nails that can often be seen in psoriasis?
- Subungual hyperkeratosis
- increased Keratine under nail
- Dystophic nail and loss of cuticle
- might make it more prone to infection
- Onycholysis and pitting
- seperation of nail from nailbed
- pitting= pits on nail
Which cells usually mediate inflammation of the skin?
- In the epidermis= neutrophils
- in the dermis= lymphocytes
What is Guttate psoriasis
Type of psoriasis (“Raindrop like) with
- many small plaqules
- presenting in teenagers and young adults
exaggabated by streptococcal infections
What is Palmoplantar pustulosis?
blister-like sores on the palms of your hands and the soles of your feet
What is Generalised pustular psoriasis?
What is its prognosis?
Many pustulars form due to clustering of neutrophils in epidermis
What are the possible causes of postules?
- Infection
- Drug reaciton
- Psoriasis
- sterile neutrophil accumulation
What is the clinical presentation of Acne?
Present with
- whitehead closed comedo
- blackheads (open comedo)
- pustules
- nodules
- papules
Explain the pathophysiology of acne
- Overproduction of keratine by keratinocytes that line the sebaceous follicle blocks hair follicle/sebacous gland –> formation tof micro comodo
- Accumulation of sebum and dead cells around hair follicle
- Infection with bacteria Propionibacterium acnes and further production of sebum
- Rupture with excretion and pus going into adjacent areas/follicles
- Might be also influenced by
- genetic predisposition
- other comedone formation
- androgen stimmulation —> leding to sebum production
- propionibacterium acnes
What is Bullus pemphigoid?
It is a condition that causes separation of the epidermis from the dermis leading to deep blister formation
