DERMATOLOGY REVISION
Skin signs of systemic disease
- Necrobiosis lipoidica diabeticorum - diabetes; granulomatous disorder of shins, not
painful; betamethasone 0.1% cream
- Granuloma annulare - diabetes; nil
- Acanthosis nigricans - endocrine diseases which increase weight, GI cancer; abdo CT;
tx cause
- Dermatitis herpetiformis - coeliac disease; tTG; dapsone
- Lupus - rash associated with photosensitivity, alopecia, livedo reticularis and Raynaud’s;
ANA, anti-dsDNA; SLE - prednisolone, DLE/SCLE - betamethasone 0.1% cream
- SLE - malar; DLE discoid, scarring; SCLE maculopapular, non-scarring
- Erythema multiforme - herpes simplex; target lesions; clobetasol 0.05% cream or
prednisolone
- Minor - hands/feet → face/trunk
- Major - systemic sx, mucosal involvement
- Erythema nodosum - NO (idiopathic), Drugs (sulphonamides, amoxicillin), OCP,
Sarcoidosis/TB, UC/Crohn’s, Micro (strep pyogenes); inflammation of subcutaneous fat
on shins, painful; CXR; nil
- Pyoderma gangrenosum - UC (p-ANCA)/Crohn’s (ASCA); enlarging painful ulcer;
prednisolone
- Dermatomyositis - myositis, photosensitive rash (shawl sign), lilac heliotrope eyelids,
Gottron papules, nail fold erythema; CK, ANA, anti-Mi-2 ± anti-Jo-1, skin biopsy, muscle
biopsy, EMG (fibrillation potentials); prednisolone
- Dermatomyositis - inflammation of voluntary muscles (myositis) causing proximal
muscle weakness w/ rash
- Polymyositis - myositis w/o rash
- Antisynthetase syndrome - myositis w/ interstitial lung disease, anti-Jo-1
Dermatological emergencies
- Erythroderma - idiopathic, psoriasis, dermatitis, drugs; erythema affecting >90%, skin
feels hot but patient feels cold, pruritis; Sezary cells if due to CTCL
- SJS and TEN - drugs (allopurinol, sulphonamides, NSAIDs, anticonvulsants); skin
detachment affecting <10% SJS, 10-30% SJS/TEN overlap, TEN >30%; Nikolsky +ve
- Necrotising fasciitis - strep pyogenes; pain out of proportion, dusky purple rash and
oedema → blisters → necrosis
Infective skin disorders
- Impetigo - staph aureus; golden crusting; localised - fusidic acid cream, widespread -
flucloxacillin
- Herpes simplex - HSV; painful gingival, mouth or genital ulcers; aciclovir
Skin signs of systemic disease
- Necrobiosis lipoidica diabeticorum - diabetes; granulomatous disorder of shins, not
painful; betamethasone 0.1% cream
- Granuloma annulare - diabetes; nil
- Acanthosis nigricans - endocrine diseases which increase weight, GI cancer; abdo CT;
tx cause
- Dermatitis herpetiformis - coeliac disease; tTG; dapsone
- Lupus - rash associated with photosensitivity, alopecia, livedo reticularis and Raynaud’s;
ANA, anti-dsDNA; SLE - prednisolone, DLE/SCLE - betamethasone 0.1% cream
- SLE - malar; DLE discoid, scarring; SCLE maculopapular, non-scarring
- Erythema multiforme - herpes simplex; target lesions; clobetasol 0.05% cream or
prednisolone
- Minor - hands/feet → face/trunk
- Major - systemic sx, mucosal involvement
- Erythema nodosum - NO (idiopathic), Drugs (sulphonamides, amoxicillin), OCP,
Sarcoidosis/TB, UC/Crohn’s, Micro (strep pyogenes); inflammation of subcutaneous fat
on shins, painful; CXR; nil
- Pyoderma gangrenosum - UC (p-ANCA)/Crohn’s (ASCA); enlarging painful ulcer;
prednisolone
- Dermatomyositis - myositis, photosensitive rash (shawl sign), lilac heliotrope eyelids,
Gottron papules, nail fold erythema; CK, ANA, anti-Mi-2 ± anti-Jo-1, skin biopsy, muscle
biopsy, EMG (fibrillation potentials); prednisolone
- Dermatomyositis - inflammation of voluntary muscles (myositis) causing proximal
muscle weakness w/ rash
- Polymyositis - myositis w/o rash
- Antisynthetase syndrome - myositis w/ interstitial lung disease, anti-Jo-1
Dermatological emergencies
- Erythroderma - idiopathic, psoriasis, dermatitis, drugs; erythema affecting >90%, skin
feels hot but patient feels cold, pruritis; Sezary cells if due to CTCL
- SJS and TEN - drugs (allopurinol, sulphonamides, NSAIDs, anticonvulsants); skin
detachment affecting <10% SJS, 10-30% SJS/TEN overlap, TEN >30%; Nikolsky +ve
- Necrotising fasciitis - strep pyogenes; pain out of proportion, dusky purple rash and
oedema → blisters → necrosis
Infective skin disorders
- Impetigo - staph aureus; golden crusting; localised - fusidic acid cream, widespread -
flucloxacillin
- Herpes simplex - HSV; painful gingival, mouth or genital ulcers; aciclovir
