Derm Flashcards
Difference between pemphigoid and pemphigus
Pemiphigoid- autoantibodies made against basement antigens causing DEJ splitting
Pemphigus- autoantibodies against protein demsogloein that connects epithelial cells together
What immune reaction is contact irritant dermatitis
Delayed type IV hypersensitivity mediated by T-lymphocytes
Where do acral lentignous melanomas occur
soles, palms and nail beds
What does eczema herpeticum look like
Characterised by fever, small punched out erosions
1st line for rosacea
Ivermectin then metranidazole if contraindicated
Which layer do keratinocyte stem cells generate
Stratum basale
What layer is only present in thick skin
Stratum lucidum
What is the stratum corneum
Dead denucleated keratinised cells that shed off
What collagen fibres compose the dermis
Type 1 and type 3 collagen fibres
Where do melanocytes come from
Neural crest in stratum basale
What condition is nikolsky sign negative
Bullous pemphigoid as it is deeper
What is erysipelas
From of superficial cellulitis affecting upper layers of dermis usually due to insect bite
SCC with a diameter of ? is associated with poor prognostic outcomes?
> 20mm
Treatment of psoriasis
1st line- potent steroid and vit d
2nd- if getting worse remove steroids and give vit 2 alone x2 a day
3rd- still worse give steroids x2day
What is guttate psoriasis
Reactive psoariais to strep B infection
Describe lichen planus
Disease of Ps:
Purple, pruritic, polygonal papuluous on flexural surface. Mx- topicals
Describe bullous pemphigoid
Anti-hemidesmosome antibodies (IgG) react with hemidesmosomes below the junction (type 2 hypersensitivity), cysts not popped, older people.
IgG and complement deposition around the basement membrane
Mx- steroids, tetracycline abx
Describe pemphigus vulgaris
IgG antibodies against desmosomal proteins leads to loss of keratinocyte adhesion in skin and mucous membranes. Causes superficial blistering- antibodies on surface.
Cysts popped, younger people. nikolsky sign positive
Biopsy- chicken wire deposition of IgG in epidermis
MM- topics steroids and topical
What is the reticular layer of the dermis
Hair roots, apocrine and eccrine glands, nerve endings, blood vessels. It is deep to the papillary dermis
Clinical presentation of NF
- Cafe au lait macules
- Neurofibromas
- Plexiform neuroma - diffuse
- Axillary or inguinal freckling
- Optic glioma
- 2 or more Lisch nodules
- Distinctive bony lesion
What antibodies are associated with drug induced lupus
Anti-histone antibodies
What is erythema nodosum commonly caused by
Crohns disease
What is the fifth layer of skin only present in thick skin
Stratum Lucidum
What metabolism happens in the skin
Vit D metabolism:
Thyroid hormone metabolism
What drug usually causes a maculopapular drug eruption
Penicillin
Ash leafed macules
Tuberous sclerosis
mnemomic for skin layers
‘British and spanish grannies love cornflakes’
Deep to superficial:
Basale, spinosum, granulosum, lucidum, corneum
What are basal cells
Cuboidal stem cells that are precursors to keratinocytes
Where are keratinocytes found dead
In the corneum
Which layer are langerhan cells found
Spinosum layer
Which layer are merkel cells found
Basale layer between keratinocytes and nerve fibres.
What are dermal papilla
Dermal connective tissue that increase connections between the layers
Where does acral lentiginous melanoma occur
Palms, sole, under nails. Most common in dark skinned patients
