Dermatology - Skin & Systemic Disease

Question 1

What is acanthosis nigricans?

Answer 1

Skin disorder characterised by hyperpigmentation** (darkening) and **hyperkeratosis (thickening) of the skin.

Question 2

What underlying malignant systemic disease can acanthosis nigricans indicate?

Answer 2

GI malignancy → especially stomach

Question 3

Acanthosis nigricans can be a sign of a benign underlying condition. What is the most common?

Answer 3

Obesity related - associated with insulin resistance (e.g. T2DM)

Question 4

Give some other benign causes of acanthosis nigricans

Answer 4

• 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

Question 5

Location of acanthosis nigricans?

Answer 5

Skin folds (axilla, groin, back of neck)

Question 6

Presentation of acanthosis nigricans?

Answer 6

• Often velvety texture
• Can be papillomatoses (finger-like growths) and skin tags occur in surrounding skin

Question 7

What is necrobiosis lipoidica?

Answer 7

A rare granulomatous skin disorder.

Question 8

What systemic disease can necrobiosis lipoidica indicate?

Answer 8

Diabetes (insulin dependent)

Question 9

Presentation of necrobiosis lipoidica?

Answer 9

• 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)

Question 10

Management of necrobiosis lipoidica?

Answer 10

Doesn’t always require treatment but can use:

• Topical steroids
• Oral ciclosporin
• Phototherapy

Question 11

What is granuloma annulare?

Answer 11

A common inflammatory skin condition typified clinically by annular, smooth, discoloured papules** and **plaques**, and **necrobiotic granulomas on histology.

Question 12

Who is granuloma annulare most common in?

Answer 12

Most common in children, teenagers and young adults.

Question 13

Pathophysiology of granuloma annulare?

Answer 13

Hypersensitivity reaction

Question 14

What systemic disease can granuloma annulare indicate?

Answer 14

Sometimes associated with diabetes** and **hyperlipidaemia

Question 15

Describe the plaques in granuloma annulare

Answer 15

Smooth, discoloured, thickened, annular (round)

• Affected areas only tender when knocked
• Plaques tend to change appearance slowly

Question 16

Management of granuloma annulare?

Answer 16

• Most often require no treatment as plaques disappear in several months without a scar
• Can remain for years
• Treatments include:
  
  • Steroids or imiquimod
  • Calcineurin inhibitors (tacrolimus)
  • Widespread → systemic immunosuppressants or phototherapy

Question 17

What is erythema nodosum?

Answer 17

An inflammatory disorder affected subcutaneous fat.

Question 18

Pathophysiology of erythema nodosum?

Answer 18

Hypersensitivity response (often due to recent infection in otherwise healthy individuals).

Question 19

What systemic disease can erythema nodosum indicate?

Answer 19

Infection, drugs and inflammatory diseases

Question 20

Who is erythema nodosum more common in?

Answer 20

Age 20-45 y/o.

More common in women.

Question 21

Give some diseases that can trigger erythema nodosum

Answer 21

• Group A strep
• primary TB
• pregnancy
• malignancy
• IBD
• chlamydia
• leprosy

Question 22

Give some drugs that can trigger erythema nodosum

Answer 22

NSAIDs, amoxicillin, COP, sulfonamides

Question 23

Presentation of lesions of erythema nodosum?

Answer 23

• Presents as tender red nodules on anterior shins (sometimes thighs and forearms).
• Appear for 1-2 weeks which appear like bruises as they resolve

Question 24

Management of erythema nodosum?

Answer 24

• Treat underlying infection
• Bed rest, supportive bandages & anti-inflammatories
• Normally subsides in 3-6 weeks

Question 25

What is pyoderma gangrenosum?

Answer 25

Auto-inflammatory disease – excessive immune response due to a neutrophil dysfunction (neutrophilic dermatosis) that presents as a rapidly enlarging, very painful ulcer.

Question 26

What age group does pyoderma gangrenosum typically affect?

Answer 26

>50 y/o

Question 27

What underlying disease can pyoderma gangrenosum be associated with?

Answer 27

Thought to be a reaction to a disease e.g.:

• IBD
• Rheumatoid arthritis
• Myeloid blood disorders (leukaemia)
• PAPA syndrome

BUT 50% of those affected don’t have these risk factors.

Question 28

Describe the lesion in pyoderma gangrenosum

Answer 28

• Fast growing, highly painful ulcer
• Purple, undermined borders
• May be multiple ulcers (not gangrenous)

Question 29

Management of pyoderma gangrenosum?

Answer 29

• Remove necrotic tissue and provide expert wound care
• Avoid surgical debridement when ulcers are active as may lead to increased ulcer size
• Abx not useful UNLESS 2ary infection
• Steroids → given topically or systemically depending on size/spread