Dermatology - Skin & Systemic Disease Flashcards
What is acanthosis nigricans?
Skin disorder characterised by hyperpigmentation** (darkening) and **hyperkeratosis (thickening) of the skin.
What underlying malignant systemic disease can acanthosis nigricans indicate?
GI malignancy → especially stomach
Acanthosis nigricans can be a sign of a benign underlying condition. What is the most common?
Obesity related - associated with insulin resistance (e.g. T2DM)
Give some other benign causes of acanthosis nigricans
- Can be syndromic → Cushing’s disease, PCOS
- Can be drug induced (e.g. insulin use, nicotinic acid, systemic steroids, hormone treatments)
- Can be hereditary (autosomal dominant)
- Can occur in healthy individuals, mainly African-American – most commonly velvety lesions over hands and feet
Location of acanthosis nigricans?
Skin folds (axilla, groin, back of neck)
Presentation of acanthosis nigricans?
- Often velvety texture
- Can be papillomatoses (finger-like growths) and skin tags occur in surrounding skin
What is necrobiosis lipoidica?
A rare granulomatous skin disorder.
What systemic disease can necrobiosis lipoidica indicate?
Diabetes (insulin dependent)
Presentation of necrobiosis lipoidica?
- One or more tender yellow/brown patches on lower legs for several months – years
- Centre of patch is shiny, pale, thin with telangiectasia (visible blood vessels)
Management of necrobiosis lipoidica?
Doesn’t always require treatment but can use:
- Topical steroids
- Oral ciclosporin
- Phototherapy
What is granuloma annulare?
A common inflammatory skin condition typified clinically by annular, smooth, discoloured papules** and **plaques**, and **necrobiotic granulomas on histology.
Who is granuloma annulare most common in?
Most common in children, teenagers and young adults.
Pathophysiology of granuloma annulare?
Hypersensitivity reaction
What systemic disease can granuloma annulare indicate?
Sometimes associated with diabetes** and **hyperlipidaemia
Describe the plaques in granuloma annulare
Smooth, discoloured, thickened, annular (round)
- Affected areas only tender when knocked
- Plaques tend to change appearance slowly
What is erythema nodosum?
An inflammatory disorder affected subcutaneous fat.
Presentation of lesions of erythema nodosum?
- Presents as tender red nodules on anterior shins (sometimes thighs and forearms).
- Appear for 1-2 weeks which appear like bruises as they resolve
What is pyoderma gangrenosum?
Auto-inflammatory disease – excessive immune response due to a neutrophil dysfunction (neutrophilic dermatosis) that presents as a rapidly enlarging, very painful ulcer.
