Inflammatory Dermatoses Flashcards
What do eccrine glands produce and where are they found?
Eccrine sweat glands make watery sweat glands and are all over
What do apocrine glands produce and where are they found?
Apocrine sweat glands make more viscous sweat and are mainly concentrated in the axilla and groin
The matrix of the dermis is made out of what? (8)
collagen, elastin, glycosaminoglycans, connective tissue, fibroblasts, immune cells, blood vessels and nerves
5 layers of the skin? Top to bottom
Stratum cornea, stratum granulosum, stratum spinosum, stratum basale and dermis
Purpose of Merkel cells and where are they found?
Involved in sensation, they sit on the basement membrane
Purpose of dendritic cells?
APCs
Purpose of melanocytes? How to spot a melanocyte under histology?
Make melanin and protect nuclei of keratinocytes from UV damage, they look like cells with a bit of white in under histology slides
What is the stratum corneum composed of?
Dead keratinocytes
Describe the life of a keratinocyte, mention which lawyer of th e
- Keratinocytes start off in the stratum basale and proliferate, moving up the epidermis and differentiating
- Eventually they produce keratin which makes up most of the stratum corneum
- By the time they reach the stratum corneum, keratinocytes have lost their nuclei and died They form the barrier of the skin
What do defects of the stratum corneum lead to
- Defects lead to eczema
What protein glues corneocytes together
Filagrin
Filagrin does what?
glues corneocytes together
Atopy is…
tendency to develop hypersensitivity
Order that these atopic diseases tend to present in life:
food allergy, eczema, rhinitis, asthma
eczema, food allergy, asthma, rhinitis
Describe how atopic eczema can occur, starting with mutations in skin
skin has intrinsic factors such as filaggrin gene mutations that allow extrinsic factors such as allergens (dust mites), pathogens and irritants in.
These are taken in by APC and stimulate an immune response (activate CD4 cells and TH2 response). Produces IgE causing mast cells to degranulate and atopic eczema.
What does palmar hyper linearity suggest
a sign of a filagrin gene mutation and can be used to assess risk of eczema
What is a sign of a filagrin gene mutation and can be used to assess risk of eczema
palmar hyper linearity
Describe acute eczema
very red, weepy, blistery, colonised with bacteria
Describe chronic eczema
will look less red, excoriated (scratched) and lichenified (thickened looking skin and accentuation of skin lines)
Describe erythrodermic eczema
means red all over – can be used to describe severe eczema
Describe Eczema HERPETICUM
where herpes simplex proliferates on the skin in someone with eczema – this can become serious and even lead to an encephalitis
SEBORRHOEIC eczema, aka…
dandruff
PSORIASIS causes?
Genetics and environmental triggers such as stress
How does thickening of skin occur in psoriasis? Why does this lead to scaling (what cells remain in the top layer)
Genetic/environmental triggers occur. T cells then accumulate in the dermis and stimulate cytokine release especially TNF-α, this leads to neutrophils going into the epidermis and overproduction of keratinocytes leading to thickening of the skin.
The top layer is immature and hasn’t lost its neutrophils so you get lots of scaling, also leads to blood vessels dilating.
