Derm Flashcards
Main cell type in epidermis
Keratinocytes
Epidermis layers
Stratum: Germinativum Spinosum Granulosum Lucidum(palms/soles) Corneum
What is the dermis mainly made of
Collagen(fibroblasts)
Immune cells
Afferent nerves
Merkel cell(epidermis): light touch, pressure
Meissner’s corpuscle: light touch, vibration
Ruffini corpuscle: stretch
Pacinian corpuscle: pressure/vibration
Psoriasis pathology
Chronic, immune-mediated
Stressed keratinocytes release DNA
Immune complexes form
Cytokine release
Inflammation
Psoriasis symptoms
Extensor surface erythematous plaques
Psoriatic arthritis
Psoriasis management
Vit D analogues
Topical corticosteroids
Phototherapy
Atopic eczema pathology
Intensely pruritic chronic inflammation
Impaired protection against microbes
Eczema symptoms
Flexor surface erythematous plaques that itch
Eczema management
Emollients
Topical corticosteroids
Phototherapy
Biological therapy
Lupus skin symptoms
Red scaly patches
Butterfly rash on face
What to do if an infant has red rash
Test ECG in case infant has neonatal lupus(50% have heart block)
Dermatomyositis skin symptoms
Photodistributed rash:
Heliotrope rash(eyes)
Shawl sign(upper chest)
Gottron’s papules
Dermatomyositis antibodies
Anti-p155: malignancy
Anti-MDA5: digital ulcers->interstitial lung disease
Dermatomyositis investigations
Antinuclear antibodies
Creatinine kinase
LFT: ALT raised
Biopsy
Vasculitis presentations
GI bleed
Abdominal pain
Macular purpura
What is sarcoidosis and features
Granulomas, commonly lungs
Highly variable presentation
Diagnosis of exclusion
Lupus pernio
Graft vs host disease symptoms
Face involvement
Acral involvement
Diarrhoea
DRESS syndrome/SJSTEN causes
Antibiotics
Anticonvulsants
NSAIDs
DRESS syndrome presentations
Head/neck oedema
Rash
Fever
Lymphadenopathy
Result of itching
Nodular prurigo
Causes of itch without rash
Uraemia Cholestasis Iron deficiency/overload HIV Cancer Drugs Psychogenic
Scurvy presentations
Spongy gingivae
Corkscrew hair
Petechiae
Kwashiorkor presentations
Hepatomegaly
Loss of muscle mass
Soft, thin nails
Vit B3 deficiency presentations
Photodistributed erythema
Casal’s necklace
Steven-Johnson-Syndrome/Toxic Epidermal Necrolysis classification
BSA detachment:
<10% -> SJS
10-30% -> SJS/TEN
>30% -> TEN
SJSTEN pathology
Emergency
Flu like symptoms followed by skin lesions->blisters emerge->skin detaches
CKD cutaneous presentations
Prurigo
Xerosis(dryness)
Half and half nails
Calciphylaxis
Liver disease presentations(derm)
Jaundice
Muerhcke’s lines(nails)
Terry’s nails
Clubbing
S. Aures infections
Folliculitis Cellulitis Impetiginisation SSSS, toxic shock syndrome Blistering distal dactylitis Erysipelas Necrotising fasciitis
S. Pyogenes infections
Cellulitis Ecthyma Blistering distal dactylitis Erysipelas Scarlet fever Necrotising fasciitis
Pseudomonas aeruginosa infections
Folliculitis
Ecthyma gangrenosum
Animal-related infections
Erysipeloid: raw fish/meat
Borreliosis(Lyme): tick bite
Tularaemia: handling animals, tick/deerfly bites
What is a carbuncle
Furuncle(deep follicular abscess) affecting adjacent follicles
Which part of skin affected in cellulitis
Lower dermis and subcutaneous tissue
Oedema causing infections
Cellulitis
Erysipeloid
Necrotising fasciitis management
Prompt diagnosis
Broad spectrum antibiotics and surgical debridement
Blood/tissue culture
Borreliosis presentations
1-30 days: fever, headache, secondary lesion
Neuroborreliosis: facial palsy, aseptic meningitis
Syphilis primary presentation and treatment
Chancre: painless ulcer, firm border
Painless lymphadenopathy
Syphilis progression
Secondary:
Malaise, fever, pruritus
Lues maligna(if immunosuppressed)
Tertiary:
Gumma skin lesions
Neurosyphilis
Leprosy types
Lepromatous leprosy: multiple lesions, sensation&sweating normal
Tuberculoid leprosy: few lesions, anhidrotic&numb
Herpes simplex virus types
HSV-1: saliva and secretions
HSV-2: sexual contact
HSV presentations
Burning/tingling-> urinary retention
Lymphadenopathy, malaise
Painful vesicles on erythematous base
What is roseola infantum
6th disease
HHV6
Commonly children
Most common fungal infection
Trichophyton rubrum
Scabies presentations
Flesh-coloured pruritic papules
Burrow of fine white scale
Types of lice
Head louse: pediculous humanus capitis
Body louse: pediculous humanus corporis
Pubic louse: crabs
Infestation treatment
Permethrin
Ivermectin
Melanoma pathology
Most common skin cancer Melanocyte malignancy MAPK pathway CDKN2A loss of function CTLA-4 inhibits costimulatory signal for CD8 T cell to kill tumour cell
Melanoma subtypes
Superficial spreading: horizontal&vertical
Nodular: only vertical growth
Lentigo maligna: commonly face
Acral lentiginous: commonly palms/soles
Melanoma diagnosis(ABCDE)
A: asymmetry B: border irregularity C: colour variation D: diameter >5mm E: evolving
Melanoma management and major prognostic factor for metastasis
Primary excision, 2mm peripheral margin
Sentinel lymph node biopsy
LDH: major prognostic factor(metastasis)
Immunotherapy: CTLA-4 or PDL-1 inhibition
Oncogene: BRAF or MAPK inhibition
Types of keratinocyte dysplasia
Basal cell carcinoma
Squamous cell carcinoma
Actinic keratoses
Bowen’s disease
Basal cell carcinoma pathology
Loss of function mutation->sonic hedgehog signalling pathway
p53 mutation
Almost never metastasises
Basal cell carcinoma treatment
Standard excision
Radiotherapy
Vismodegib->inhibits SHH pathway
Squamous cell carcinoma features
CDKN2A, p53 mutations
Rapidly growing
Squamous cell carcinoma treatment
Excision
Radiotherapy
Keratoacanthoma
Rapidly growing papule that resolves after months
Neck snd sun exposed areas
Difficult to distinguish from SCC
Types of cutaneous T cell lymphoma
Mycosis fungoides
Sezary syndrome
Mycosis fungoides features and treatment
Common
Takes years to diagnose
Topical corticosteroids, phototherapy, radiotherapy
Chemotherapy if advanced
Sezary syndrome triad of symptoms and treatment
Triad of: erythroderma, generalised lymphadenopathy, neoplastic T cells
Extracorporeal photophoresis
Topical corticosteroids
Kaposi sarcoma virus
HHV8
Merkel cell carcinoma virus and treatment
Polyomavirus
Treat with surgery, radiotherapy
Anti PDL1
PVL S. Aureus features
Painful
More than 1 site
Recurrent
Present in close contacts
Higher morbidity, mortality, transmissibility
Viral infections derm
HSV Varicella zoster virus HFMD(coxsackievirus) Erythema infectiosum(parvovirus B19) Rosella infantum(6th disease) Orf(parapoxvirus sheep/goats) Warts(HPV)
Sarcoidosis
Systemic granulomatous disorder(lungs common)
Diagnosis of exclusion
Lupus pernio
Carcinoid syndrome
Metastasis of malignant carcinoid tumour
Flushing, wheezing, diarrhoea, dizziness
5-HT secretion
