Dermatology Flashcards
Describe the presentation and causes of erythema multiforme
Presentation:
-Symmetricla erythematous lesions of variable morphology eg. target lesions, hives
Caused by drugs/infections:
- HSV, Mycoplasma pneumonia
- Sulphonamides, anticonvulsants
Describe the presentation and causes of Stevens-Johnson Syndrome + TEN
Presentation:
- SJS: widespread MP rash <10% of body area, blistering of skin + mucous membranes, and illness
- TEN: widespread rash >30% of body area, blistering, severe systemic illness
Usually caused by drugs: sulphonamides esp
Describe the presentation and causes of erythema nodosum
Multiple raised, tender, erythematous/purple lesions on the shins Causes: -NO cause/idiopathic -Drugs: sulphonamides -OCP -Sarcoidosis -UC + Crohn's -Micro eg TB, Brucella
Describe the aetiology + presentation of lichen planus
Aetiology: autoimmune skin condition Presents w: -Pruritic purple papules + plaques -May affect mucous membranes -Koebner phenomenon: trauma -> lesions -Wickham's striae (white lace-like)
Describe the management of lichen planus
Topical/systemic steroids
Describe the aetiology and presentation + management of bullous pemphigoid
Aetiology: autoimmune- to BM, causing separation from dermis
Presents in elderly:
-Tense blisters that do not slough on erythematous base
Mx: topical steroids (Clobetasone) or systemic
Describe the aetiology, presentation + management of pemphigus vulgaris
Aetiology: autoimmune- to desmosomes, causing acantholysis
Presents w:
-Superficial flaccid blisters that rupture (Nikolsky’s sign)
-Mucosal involvement
Management: steroids, immunosuppressants, rituximab
What is erythroderma? What are the causes?
Erythroderma is widespread (>90% of skin) reddening of the skin, assoc with exfoliation
Causes:
-Drug reaction
-Inflammatory skin conditions: psoriasis, dermatitis
-Malignancies
-HIV
Appearance: widespread erythema + warmth, scaling, weeping serous fluid
What are some risk factors for pressure sores? Where are they commonly found?
- Immobility
- Hospitalisation, esp ITU
- Impaired sensation eg spinal cord injury
Found: sacrum + buttocks, heels, ears (oxygen)
How are pressure sores categorised? What is the management?
Based on thickness + tissues involved
1: no skin loss
2: superficial skin loss
3: full thickness skin loss, up to adipose
4: full thickness loss with muscle + fascia visible
Mx
- Conservative: pressure relief, nutrition, hygiene
- Medical: antibiotics if infected
- Surgical: debridement if necrotic
Describe the presentation of urticaria and management
Presents w acutely pruritic raised wheals
Management:
-Antihistamines eg. loratidine, cetirizine hydrochloride
Which pathogen causes ringworm? Name the types of ringworm
Dermatophytes eg. trichophyton
Tinea capitis, corporis, cruris, pedis etc
Describe the presentation of ringworm + management
Itchy, erythematous rash with yellow scale
On body: annular lesions with central clearing
Mx:
- Scalp: oral terbinafine
- Body: topical eg. ketoconazole shampoo, terbinafine
What pathogen causes pityriasis veriscolor? Describe the presentation and management
Malassezia furfur
Large patches of hypopigmentation (may also be hyper in light skin) + fine scale. Spaghetti + meatballs appearance on microscopy
Mx: ketoconazole shampoo
What pathogen causes molluscum contagiosum? Describe the appearance and management
Pox virus
Multiple small, pearly papules with central umbilication
Mx: allow spontaneous resolution w/in 1 year
Describe the presentation of pityriasis rosea
Small papules + plaques in symmetrical ‘Christmas tree-like’ distribution, preceded by single larger herald patch
Describe the presentation of psoriasis
- Well-demarcated salmon pink plaques with silvery scale
- Found often on extensor surfaces eg elbows
- Morphology may be guttate (eg post-strep), plaque, etc
- Also have lichenification + fissures, Koebner phenomenon, nail changes
Describe the management of psoriasis
Conservative:
- Smoking cessation, reduce alcohol, avoid trauma
- Soap substitutes + emollients
Medical: -Topical steroids -> Calcipotriol (Vit D) -> Calcineurin inhibitors- tacrolimus \+/- Phototherapy -> Immunosuppressants- methotrexate -> Biologics
What are some examples of emollients?
Dermol, Diprobase
What are the different topical steroids? List in order of strength
Hydrocortisone 1%
Eumovate aka clobetasone
Betnovate aka betamethasone
Dermovate aka clobetasol
Describe the presentation of atopic eczema
- Itchy, dry skin +/- erythema
- Tends to be flexural surface eg. antecubital fossa, and around eyes
- Usually in patches, can be discoid
- > over time lichenification + fissuring
Describe the management of atopic eczema
Conservative:
-Soap substitutes + daily emollients for everyone
Medical:
- Topical steroids during flares eg. hydrocortisone 1%
- Can increase steroid strength, topical calcineurin i
- > phototherapy
Describe the presentation and management of seborrheic dermatitis
Non-itchy scaling, typically on scalp (dandruff), eyebrows + nasolabial folds
Mx: topical steroids + antifungals eg. ketoconazole shampoo
What are actinic keratoses? Describe the appearance
Pre-malignant skin condition (pre-SCC)
Scaly patch on sun-exposed skin
