1
Q
What are the four layers of epidermis?
A
- Keratin layer
- Granular layer
- Prickle cell layer
- Basal layer
2
Q
components of keratin layer
A
- Corneocytes (80% keratin and filaggrin)
- lamellar granules (secrete lipids)
3
Q
components of granular layer
A
- keratohyalin granules
- odland bodies (contain secretory organelles)
4
Q
What is the origin of the cornified envelope
A
Granular layer
5
Q
Components of prickle cell layer
A
- desmosomes (connections)
- keratin filiaments
- langerhans cells
6
Q
Components of basal layer
A
- keratin filaments
- Merkel cells (mechanoreceptors)
highly metabolically active: keratinocytes created here and migrate upwards (takes 28 days)
7
Q
Key feature of langerhans cells
A
- birbeck granules
- look like tennis rackets
8
Q
What is in the dermis?
A
- connective tissue
- fibroblasts
- macrophages, mast cells, lymphocytes, langerhans cells
- collagen and elastin fibres
- blood vessels
9
Q
Pacinian corpuscules sense what?
A
pressure
10
Q
Meissner’s corpuscules sense what?
A
Vibration
11
Q
Which enzyme effected in Erythropoetic protoporphyria ?
A
- ferrochelatase
- genetic ->dysfunctional protein
12
Q
Which enzyme affected in porphyria cutanea tarda?
A
- uroporphyrinogen
- lack or enzyme due to it being used or break down e.g. excessive alcohol, haemochromatosis, hepatitis
13
Q
what enzyme is affected in acute intermittent porphyria
A
- PBG deaminase
- genetic -> dysfunctional protein
14
Q
Bacteria which may be responsible for necrotising fasciitis
A
- mixed anaerobes/coliforms (post abdominal surgery)
- group A strep (pyrogenes)
15
Q
Investigation for Tinea
A
- florescence under woods lamp
- microscopy
- take scrapings from edge of lesions
16
Q
Treatment for tinea/ candida
A
-clotrimazole cream
17
Q
Herpes responsible for oral lesions
A
-HSV type 1
18
Q
Herpes responsible for genital lesions
A
- HSV type 1
- HSV type 2
19
Q
What is Aciclovir?
A
-analogue of guanosine
20
Q
Types of HPV which cause cervical cancer
A
16 and 18
21
Q
Types of HPV which cause genital warts
A
6 and 11
22
Q
What causes erythema infectiosum/ slapped cheek disease?
A
erythrovirus B19
23
Q
symptoms of primary phase of syphilis
A
- painless chancres
- occur at site of entry
24
Q
symptoms of secondary phase of syphilis
A
- red rash all over body
- prominent on soles, palms and mucous membranes
- ‘snail track ulcers’
25
Symptoms of tertiary phase syphilis
- CNS
- gummatous
- CVS
-widespread effects
26
Bacteria which causes lyme disease
Berrelia burgdorferi
27
late complications of lyme disease
heart block, nerve palsies, arthritis
28
Treatment for lyme disease
doxycycline or amoxicillin
29
Pathological appearance of psoriasis
- epidermal hyperplasia
- parakeratosis
- absent granular layer
- elongated and clubbed ret ridges
- neutrophilic and lymph histocytic infiltrate
30
example of vitamin D3 drugs
- calcipotriol
| - tacalcitol
31
What is pathological appearance of lichen planus?
- hyperkeratosis
- dense T cell infiltration in dermo-epidermal junction
- liquefactive degeneration of basal layer
32
Which areas are commonly involved in lichen planus?
- flexors
- lower legs
- wrists
- mouth
- anogenital region
33
Which populations is pemphigus vulgaris more common in?
- indian
| - jewish
34
Pathophysiology of pemphigus vulgaris
-IgG auto-antibodies against desmoglein 3
35
Where is the split in pemphigus vulgaris
- superficial intra-epidermal split
| - just above basal layer
36
Pathophysiology of bullous pemphigoid
-antibodies agains haemosdesmosomes
37
Where is the split in bullous pemphigoid?
between basal cells and basement membrane
38
investigation for bullous pemphigoid
- immunofluorescence
| - will show IgG and complement deposition around basement membrane
39
Who is likely to present with dermatitis herpatiformis?
- young adult males
| - with coeliac disease
40
possible causes of rosacea
- skin mite dermodex
| - vasmotor instability of blood vessels
41
treatment of rosacea
- oral tetracyclines
| - topical metronidazole
42
possible cause of atopic dermatitis
- loss of function of filaggrin protein
| - is responsible for maintaining the epidermal barrier
43
What is lichen simplex?
-chronic scratching/rubbing without an underlying cause
44
Cause of seborrheic dermatitis
- overgrowth of pityrosporum ovale fungus
| - cutaneous immune response to the yeast it produces
45
proteins affected in tuberous sclerosis
- tuberin and hemartin
| - both are tumour regulating genes
46
is tuberous sclerosis dominant or recessive?
autosomal dominant
47
cutaneous sign which could indicate tuberous sclerosis
ash leaf macules
48
What is epidermolysis bullosa
- group of genetic skin fragility diseases
| - mutations in genes responsible for skin structure/adhesion e.g. keratin, integrins, collagen
49
Cutaneous sign of neurofibromatosis type 1
greater than 5 cafe au lait macules
50
What is seborrheic keratosis?
- benign proliferation of epidermal keratinocytes
| - gives 'stuck on' appearance
51
pathological appearance of BCC
- desmoplastic fibrous stroma
- peripheral palisading
- lots of apoptosis and mitosis
52
common mutations involved in BCC
- PTCH1
- key component of hedgehog signalling pathway
- which is important in cell proliferation and angiogenesis
53
SCC precursor lesions
- acitinic keratosis
| - bowen's disease
54
Common presentation of Bowen's disease
- older women
| - scaly patch/ plaque with irregular border on lower legs
55
Common mutations involved in malignant melanoma
- Ras
- Raf
- MAPK
-CDKN2A (familial)
56
what is breslow thickness?
- prognostic tool
| - measurement of how far a lesion extends below the granular layer
57
what does a breslow thickness less than 1mm indicate?
- good prognosis
| - 50-100% 5y survival
58
if breslow thickness greater than 4mm what is the 5y percentage survival?
50%
59
What is xeroderma pigmentosum
-inability to repair DNA damage from UV light
60
example of spongiotic intra-epidermal oedema
eczema
61
example of psoriasiform-elongation of the rete ridges
psoriasis
62
example of lichenoid basal layer damage
- lichen planus
| - lupus
63
example of vesiculobullous blistering
- pemphigoid
- pemphigus
- dermatitis herpatiformis
64
hyperkeratosis defintion
increased thickness of keratin layer
65
parakeratosis definition
persistance of nuclei within the keratin layer
66
acanthosis definition
increased thickness of the epidermis
67
How does UVB cause skin damage?
- energy causes covalent bonding between adjacent pyrimidines (T and C) on same DNA strand
- this interferes with base pairing when DNA replicates
- can be difficult to repair correctly leading to insertion of wrong base
68
How does UVA cause skin damage
- energy causes oxidation of bases especially deoxy guanosine
- deoxy guanosisn then might misspair with deoxy adenosine
- leads to GC -> AT point mutations
69
Which UV penetrates more deeply into skin
UVA
70
Mutations involved in familial melanoma
- CDKN2A
- codes for p16 and p14
- prevent cells form activating when they contain damaged DNA
71
Which gene controls skin and hair pigment
- MC1R
| - turns pheomelanin (red/freckles) into eumelanin
72
Tinea capitis treatment
-oral terbinafine or itraconazole
73
scabies treatment
- malathion lotion
| - benzyle benzoate (but not for kids)
74
what is Ramsay hunt syndrome?
- shingles affecting facial nerve/ geniculate ganglion
| - can cause facial paralysis/ hearing loss in affected ear
75
what is herpangina?
- blistering rash at back of mouth
| - caused by enteroviruses e.g. coxsackie
76
which antibody tends to appear early in the course of infection?
-IgM
77
treatment of acne
- bensoyl peroxide (keratinolytic)
| - isotretinoin (retinoid)
78
SCC risk factors
- viral lesions e.g. HPV 16
- precursor lesions e.g. actinic keratosis, bowen's
- areas exposed to lots of sun in particular ear, lip, scalp
- sites of chronic inflammation e.g. ulcers, burns, sinuses (osteomyelitis)
79
primary intention definition
- healing of clean wound without tissue loss
- wound edges brought together with stitches
- works for laceration type injuries
80
secondary intention definition
- loss of tissue or damage prevents closure by primary intention
- wound is left and allowed to granulate
- may be packed with gauze or have drainage
- must be cleaned regularly
81
tertiary intention definition
- wound is debrided, left open and observed
| - closure can then be achieved by primary intention or tissue grafts
82
mild steroid cream
hydrocortisone 1-2%
83
moderate steroid cream
eumovate
84
potent steroid cream
betnovate
Hard stuff to remember
flashcards
Decks in class (10)
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