Dermatology Flashcards
What does ABCDE refer to with pigmented lesions?
Indications of melanoma:
Asymmetry Border (irregular) Colour 2+ Diameter: >6mm Evolution: rapid change
What is pruritis?
Itching
What is a comedone?
A plug in a sebaceous follicle containing sebum and debris (open = blackheads / closed = whiteheads).
[present in acne]
What is Koebner phenomenon?
When a skin disorder is triggered by skin trauma e.g. psoriasis.
What is a macule?
A flat, small area of altered colour e.g. freckles.
If its large its called a patch e.g. port wine stain.
What is a papule?
A solid, raised lesion <0.5cm in diameter e.g. xanthomata.
What is a nodule?
A solid, raised, lesion >0.5cm in diameter.
What is a vesicle?
A raised, clear fluid filled lesion <0.5cm in diameter e.g. eczema or chicken pox.
What is a bulla?
Raised, clear fluid filled lesion >0.5cm in diameter
What are striae?
Linear areas which progress from purple to pink to white e.g. stretch marks of pregnancy or cushings.
What is koilonychia, give a cause?
Spooning of the nails.
Iron deficiency anaemia
GI malignancy
Coeliacs
Give a cause of clubbing
Lung cancer
Heart failure
Inflammatory bowel disease
Give two functions of skin
Temperature regulation
Protective barrier
Sensation
Vit D synthesis
What are the 4 main types of cells in the epidermis?
Keratinocytes
Melanocytes
Langerhans (immune response)
Merkels (nerve sensation)
What are the 4 layers of the epidermis from inner to outer?
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum
(Skin regenerates every 30 days from inner to outer)
What are the 4 stages of wound healing?
Haemostasis: Vasoconstriction + clot formation
Inflammation:
Vasodilation, neutrophil migration and phagocytosis.
Proliferation:
Granulation, angiogenesis, and re-epithelialisation.
Remodelling:
Collagen reorganisation and scar maturation.
What is erythema multiforme? How does it differ from Stevens Johnson Syndrome and Toxic Epidermal Necrosis?
Inflammatory condition often caused by HSV presenting with target lesions.
[Only one mucosal surface max is affected]
SJS is more extreme with multiple mucosal surfaces involved (often drug caused).
TEN is the most extreme form, often caused by drug reaction with full thickness epidermal necrosis.
What is erythema nodosum?
A mild hypersensitivity reaction to various bacteria or chronic health conditions such as cancer. Presents as tender nodules on the shins especially.
How quickly should contacts of a patient with meningococcal septicaemia be treated with prophylactic antibiotics?
Within 14 days of exposure
[Rifampicin]
What is the most common cause of meningococcal septicaemia?
Neisseria Meningitidis
[G-ve diplococcus]
Give three symptoms of meningitis
Headache Fever Myalgia Non-blanching rash Photophobia
What is erythroderma?
AKA ‘Red skin’
Widespread ~90% of skin surface becomes inflamed, oedematous and scaly (exfoliative). Caused by existing skin conditon e.g. eczema, psoriasis or drug reaction.
Treatment: Emollients, Topical steroids, Treat underlying cause.
What is the cause and treatment for eczema herpeticum?
Cause: HSV
Treatment: Antivirals and antibiotics to prevent secondary infection.
[Tend to be systemically unwell]
What is the common cause of necrotising fasciitis?
Group A haemolytic strep
[76% mortality!]
What is the difference between Erysipelas and Cellulitis?
Erysipelas is a superficial form of cellulitis involving only the dermis and upper subcutaneous tissue.
Cellulitis affects the deep subcutaneous tissue.
What are the two common causes of cellulitis?
Strep pyogenes
Staph aureus
What antibiotic would you use to treat cellulitis?
Flucloxacillin
Benzylpenicillin
A child presents with pearly, papules over their back and trunk. What do you suspect?
Molluscum Contagiosum
What is the cause of bullous pemphigoid?
Autoimmune where IGG/E attacks the basement membrane causing tense fluid filled bullae.
What is the treatment for bullous pemphigoid?
Potent topical steroids
Emollient e.g. diprobase
Immune suppression e.g. azathioprine.
What is the difference between bullous pemphigoid and pemphigus vulgaris?
BP is deeper (at the dermo-epidermal junction and therefore the blisters are tense).
PV is more superficial so the blisters rupture more easily.
Name two skin conditions sensitive to UV light
Psoriasis
Eczema
Rosacea
SLE
What is Rosacea?
Red/flushing of the face in older people 30-60yo. Particularly affects celtic people.
[Rhinophyma = the bulbous nose commonly seen]
What is the treatment for atopic eczema?
Topical emollient
Mild corticosteroid
Antihistamine
Alternative soap e.g. dermol
What is the difference between contact dermatitis and eczema?
Contact dermatitis is eczema caused by direct skin contact with the allergen.
Which is the stronger topical steroid. eumovate or dermovate?
Dermovate. Only used for severe cases.
A patient with a history of eczema presents as systemically unwell with punched out lesions and fever, what do you suspect?
Eczema Herpeticum
Caused by HSV 1 or 2.
What are the 4 types of psoriasis?
Plaques (most common)
Guttate (small red spots)
Erythrodermic (like severe burns)
Pustular (multiple white pustules)
How is psoriasis treated?
Emollients Vitamin D Corticosteroids Coal Tar Immune suppression e.g. methotrexate
What is the treatment of pressure sores?
Mobilisation (prevention)
Warm the area (perfusion)
Antibiotics
Surgical debridement
Negative pressure wound vac
Skin grafts
How do arterial and venous ulcers differ?
Arterial ulcers:
- Pale
- Cold to touch
- Absent periph pulses
- Punched out
- Typically on toes
Venous:
- Swollen
- Red
- Irregular border
- Typically lower leg
How do you treat venous ulcers?
Elevate legs
Debridement (chemical/magots)
Grafts
Compression devices
How do you treat/prevent arterial ulcers?
Surgical revascularisation Avoid cold Analgesia Exercise Diabetic control Stop smoking
Give two risk factors for malignant melanoma
[MRISK]
Moles [>50 atypical] Red hair Inability to tan Sunburn Kin [Fhx]
What is the first line treatment for SCC?
Initial biopsy (incisional) then wide excision.
[Radiotherapy and photodynamic therapy is also an option]
What is Bowen’s disease?
A superficial keratinocytic dysplasia and precursor to SCC.
Actinic keratosis –> Bowen’s –> SCC [if untreated]
Which is more invasive BCC or SCC?
SCC is more invasive and spreads via the lymphatic system.
What is a dermatofibroma?
A non cancerous raised lump that resembles an insect bite.
Biopsy and if confirmed can remove (cryotherapy) or leave.
Describe two observable features of a BCC
Pearly surface
Telangiectasia
Non pigmented
How is BCC treated?
Excision with 3-4mm margin
What is anaphylaxis?
Acute, severe hypersensitivity reaction [Type 1 - IgE mediated]
Rapid Mast cell degranulation.
Give two common causes of anaphylaxis
Latex Food allergy Hair dyes Drugs Insect stings/bites
What is the treatment for anaphylaxis?
IM adrenaline 1 in 1000
(1mg in 1ml)
IM/IV Chlorphenamine
IM/IV Hydrocortisone
Salbutamol if breathing problems.
Why is it important to monitor patients following anaphylaxis for at least 12 hours?
5-10% get a Biphasic reaction where they have a second occurrence within 12 hours.
What enzyme is diagnostic of anaphylaxis? How many samples are needed?
Mast Cell Tryptase
3 samples:
- Immediately
- 1-2 hrs post onset of symptoms
- > 24hrs post symptoms
What is the difference between anaphylaxis and anaphyactoid?
Anaphylaxis is IgE mediated.
Anaphylactoid is non-IgE mediated i.e. caused by direct Mast cell degranulation e.g. opiates, contrast, heat etc.
What is the first line treatment for acne vulgaris?
Benzoyl peroxide [1st line]
Topical Retinoid
Oral antibiotics e.g. doxycycline or lymecycline.
COCP
[NB: Steroids are not NICE recommended]
How is actinic keratosis aka solar keratosis treated?
Cryotherapy Shave Curettage Electrocautery Excision Diclofenac 5-Fluorouracil Imiquimod Photodynamic therapy
What is the treatment for tinea pedis (athlete’s foot)?
Imidazole / Clotrimazole / Miconazole
Whitfield ointment (Benzoid acid, Salicylic acid)
Tipical steroid
Antibiotics if infected.
How would you treat asymptomatic carriers of tinea capitis?
Antifungal shampoo
How woul dyou investigate tinea capitis?
Skin scrapings must be analysed in a lab before treatment.
What are the three tinea infections?
Tinea capitis (head) Tinea corporis (body) Tinea pedis (foot)
What are seborrhoeic keratoses?
Benign Warty plaques Occur commonly with age Cobble-stone surface. (Start as flat)
Can be removed (shaved, curettage, cautery etc) or left alone.
Unknown cause
