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.
What is acanthosis
- Epidermis becomes thicker in psoriasis
What is hyperkeratosis
- Stratum corneum becomes thicker in psoriasis
What is parakeratosis
- Individual cells aren’t losing nuclei in psoriasis
- Stratum corneum becomes thicker in psoriasis is known as ….
hyperkeratosis
- Epidermis becomes thicker in psoriasis is known as ….
acanthosis
- Individual cells aren’t losing nuclei in psoriasis is known as ….
parakeratosis
Explain what happens in psoriasis, mention what forms pustules, and what causes the red colour and what changes are driven by lymphocytes
- Epidermis becomes thicker (acanthosis)
- Stratum corneum becomes thicker (hyperkeratosis)
- Individual cells aren’t losing nuclei (parakeratosis)
- Influx of neutrophils within epidermis – can form pustules
- Dilatation of blood vessels in the dermis (gives the red colour)
- Lymphocytes within the dermis that drive this immune reaction (there are also exess cytokines and TNFalpha)
Describe CHRONIC PLAQUE psoriasis
Salmon pink plaques with a silvery scale, very well defined
Describe psoriasis VULGARIS
Well-demarcated, erythematous plaques with thick, yellowish scale and desquamation on sites of pressure arising on the plantar feet and palms
3 SIGNS OF NAIL PSORIASIS:
PITTING
SUBUNGUAL HYPERKERATOSIS Build-up of keratin under the nail – leads to dystrophic nail and loss of cuticle
ONYCHOLYSIS Nail plate lifts off the nail bed
Describe GUTTATE psoriasis
pattern of psoriasis is ‘rain drop’, usually found on the trunk and occurs after streptococcus infection (throat/blood test) – usually affects young people and can persist for weeks or months
What infection does guttate psoriasis often occur after
streptococcus
Describe PALMOPLANTAR PUSTULOSIS
Psoriasis where, instead of plaques on the body, someone gets pustules on the palms of the hands and soles of the feet
Describe GENERALISED PUSTULAR psoriasis
Patients are febrile, malaise, tachycardic, toxic (high pulse rate, low BP etc.). Cause could be infections or psoriasis or drug reaction.
What is ACNE disease of in the skin
- Disease of the pilosebaceous unit
what is the 2ndary infection in acne?
PROPIONIBACTERIA ACNES
What causes comedone formation
caused by hyperkeratinisation of the neck/infundibulum of a follicle
4 things that contribute to acne?
genetic predisposition
- Increased sebum production
hyperkeratinisation leading to Thickening of the infundibulum (forms blackheads)
What is BULLOUS PEMPHIGOID
- Autoimmune condition with production of an auto-antibody that acts against a protein in the basement membrane (BM between epidermis and dermis)
What is the skins basement membrane between
Epidermis and dermis
What antigens are attacked by autoantibodies in bullies pemphigoid
BPAg1 and BPAg2 (bullous pemphigoid antigen 1 and 2)
Bullous pemphigoid usually affects people of what age
elderly patients, starts off as rash and then blisters develop and progress
How does bullous pemphigoid Start and how does it cause mortality
- Tense blisters
- Usually in elderly patients, starts off as rash and then blisters develop and progress
- Without treatment, the blisters get infected and cause death by sepsis
What causes EPIDERMOLYSIS BULLOSA:
Genetic condition causing a problem with the basement membrane zone
What causes PEMPHIGUS VULGARIS
- Auto-antibody directed against a component of the hemi-desmosome within the epidermis
Target of the antibody in pemphigus vulgaris?
DESMOGLEIN 1 and 3
What does pemphigus vulgarisms cause
- Blisters are superficial
- Blisters break down, causing erosions
What is the desmosome
The connection between keratinocytes
