Dermatology Flashcards
How do you differentiate between a first degree and second degree burn? (aka superficial vs partial thickness)
Superficial: epidermis only
Partial thickness: dermal layers
If the epidermis moves around when skin is rubbed, it is a partial thickness burn
Remember that a single burn likely has patches of different thicknesses
How do you calculate burns area?
Only include partial and full thickness areas
When should fluid be given in burns?
If Total Body Surface Area is >15% in adults or >10% I children
First half of the fluid given in the first 8 hours after the burn, second half over the next 16 hours
How do you calculate how much fluid to give in a burn?
4mls x TBSA burn % x weight
What is an inhalation injury in burns?
Thermal injury or chemical injury o the airway
Systemic effects from toxins
Hypoxia/asphyxia
What psychogenic underlying causes can cause itching without a rash?
Anorexia
Delusions of parasitosis
OCD
What neurogenic underlying causes can cause itching without a rash?
Post CVA
MS
Prior disease
What endocrine underlying causes can cause itching without a rash?
Hyper/hypothyroidism
Diabetes
What liver problems can cause itching without a rash?
Cholestatic
PBC
Hep C
Cholestasis of pregnancy
What renal problems can cause itching without a rash?
Chronic renal failure
Acute retention
What malignancy can cause itching without a rash
Pancreas
Carcinoid
Lung
What blood disease can cause itching without a rash?
Polycythaemia rubra vera
Fe def. anaemia
Haem malignancy
Mastocytosis
HIV
What drugs can cause itching without a rash?
Opiates
Beta blockers
Antibiotics
What medications can be used in androgenic alopecia?
Finasteride 1mg daily
Women: Minoxidil 2-5% lotion, Anti-androgen cyproterone acetate with ethinyl oestradiol
Spironolactone and metformin are also sometimes used
What can be used in the management of alopecia areata?
Topical or intralesional corticosteroids
What prognostic factors in alopecia areata suggest poor prognosis?
Nail pits
Widespread hair loss
What are the differential diagnoses you need to rule out in scarring alopecia?
Infection and inflammatory dermatosis - need to skin biopsy
What are the common causes of nail dystrophy?
Fungal infection, peripheral vascular disease, severe Raynauds, psoriasis, trauma
What is onycholysis?
Premature separation of the nail plate from the nail bed
When does onycholysis often happen?
Psoriasis
Tinea and drug eruptions
When are nail pits found?
Psoriasis
Eczema
Alopecia areata
What is leukonychia associated with?
Long-standing systemic disease
Cirrhosis
Diabetes mellitus
Cardiac failure
Severe anaemia
What are splinter haemorrhages associated with?
Trauma
Autoimmune rheumatic disease
Endocarditis
What are some causes of clubbing?
Lung disease
Cyanotic congenital heart disease
IBD
Cirrhosis
Hyperthyroidism
What malignancy are all chronic ulcers at risk of transforming into?
Marjolin’s squamous carcinoma
What can cause photodermatoses?
Atopic eczema
SLE
Lichen planus
Drug eruptions (e.g. amiodarone, thiazides or tetracycline)
Polymorphic light eruption - 4-6 hours after sun exposure
Solar urticaria
Porphyrias
Pellagra
What are porphyrias?
Deficiencies in the enzymes synthesising haem. Related to alcohol and the COCP.
Can lead to liver damage and cirrhosis due to iron overload
What is pellagra?
Deficiency in niacin - Vit B3
What is the classic tetrad of symptoms in pellagra?
Diarrhoea
Dementia
Dermatitis
Death
What is the classic cutaneous manifestation of pellagra?
Casal’s necklace
