Skin & Systemic Disease

Question 1

What is acanthosis nigricans?

Answer 1

a skin disorder characterised by hyperpigmentation (darkening) and hyperkeratosis (thickening) of the skin

Question 2

What is the texture of acanthosis nigricans like?

Answer 2

it often has a velvety texture

there can be papillomatoses (finger-like growths) and skin tags

Question 3

Which parts of the body are usually affected by acanthosis nigricans?

Answer 3

• occurs in skin folds (axilla, groin, back of neck)
• can also appear on mucous membranes and the palms/soles

Question 4

What causes acanthosis nigricans?

What is the main symptom?

Answer 4

the cause is unknown but it is thought to be related to insulin resistance

it is itchy, particularly when associated with underlying malignancy

Question 5

What are the 2 different types of acanthosis nigricans?

Answer 5

benign & malignant

benign is much more common

Question 6

What is the most common type of benign acanthosis nigricans?

Answer 6

obesity-related

Question 7

What is syndromic benign acanthosis nigricans?

Answer 7

where acanthosis nigricans occurs in patients with underlying syndromes

e.g. Cushing’s disease / polycystic ovarian syndrome (PCOS)

Question 8

When do lesions manifest in hereditary benign acanthosis nigricans?

Answer 8

this is an autosomal dominant condition in which lesions can manifest at any age

Question 9

Which drugs tend to trigger drug-induced acanthosis nigricans?

Answer 9

• nicotinic acid
• systemic steroids
• insulin
• hormone treatments

Question 10

What type of people tend to be affected by acanthosis nigricans when they are otherwise healthy?

Answer 10

Dark skinned individuals, particularly those of African-American background

this presents as velvety lesions over the upper surfaces of the hands and feet

Question 11

What is malignant acanthosis nigricans often associated with?

Answer 11

90% of cases are associated with GI malignancy (especially stomach)

Question 12

What is the treatment for acanthosis nigricans?

Answer 12

Treat the underlying cause

For the lesions themselves, treatment is only cosmetic

Question 13

What is necrobiosis lipoidica and who is usually affected?

Answer 13

it is a rare granulomatous skin disorder

it is commonly seen in people with insulin-dependent diabetes but can occur in individuals without diabetes

it is also associated with obesity, hypertension, dyslipidaemia and thyroid disease

Question 14

What does necrobiosis lipoidica look like?

Answer 14

• one or more tender yellow/brown patches on the lower legs
• slow developing over months to years
• commonly affects the shins and rarely found at other sites
• plaques can be asymmetrical and persist for many years

Question 15

What does necrobiosis lipoidica look like as it develops?

Answer 15

the centre of the patch becomes shiny and pale

it is thin with prominent telangiectasia (visible blood vessels)

Question 16

What can happen if there is minor trauma to the site of necrobiosis lipoidica?

Answer 16

this can lead to ulceration of the skin

there is then a risk of secondary bacterial infection and poor wound healing if ulceration occurs

Question 17

What are the treatments for necrobiosis lipoidica?

Answer 17

it doesn’t always require treatment

sometimes these treatments are effective:

• topical steroids
• oral ciclosporin
• phototherapy

Question 18

What is granuloma annulare and who tends to be affected?

Answer 18

it is a delayed hypersensitivity reaction to some component within the dermis with an unknown cause

it affects children, teenagers and young adults

Question 19

Which parts of the body tend to be affected in granuloma annulare?

What are the 2 different types?

Answer 19

it can occur anywhere on the body

• localised disease often affects the back of the hand and is more common in younger people / children
• widespread disease is more common in adults and can be associated with diabetes & hyperlipidaemia

Question 20

What do the plaques look like in granuloma annulare?

Answer 20

the plaques are smooth, discoloured, thickened and annular (round)

the centre of each ring is usually depressed

the affected areas are tender only when knocked and plaques tend to change appearance slowly

Question 21

What is the most common treatment for granuloma annulare?

Answer 21

most often no treatment is required as plaques disappear in several months without a scar

sometimes they can remain for years

Question 22

If treatment is needed, what are the treatment options for granuloma annulare?

Answer 22

• steroids / imiquimod / calcineurin inhibitors (tacrolimus)
• in widespread disease then systemic immunosuppressants or phototherapy can be used

Question 23

What is erythema nodusum?

Answer 23

a type of panniculitis (inflammation of subcutaenous fat)

it is a hypersensitivity response, often to recent infection, in an otherwise healthy individual

Question 24

What are common non-drug stimuli for erythema nodosum?

Answer 24

• group A streptococci
• primary tuberculosis
• pregnancy
• malignancy
• inflammatory bowel disease
• chlamydia
• leprosy

Question 25

What are common drug stimuli for erythema nodosum?

Answer 25

• NSAIDs
• amoxicillin
• oral contraceptive pill (OCP)
• sulfonamides

Question 26

What do the lesions look like in erythema nodosum?

Answer 26

• tender nodules that last for 1-2 weeks and appear as bruises as they resolve
• range in size from a cherry to grapefruit
• most common on the shins
• do not ulcerate or scar

Question 27

Who is more commonly affected by erythema nodosum?

Answer 27

• age 20-45 years
• more common in women

Question 28

What are the treatment options for erythema nodosum?

How long does it take for the condition to resolve?

Answer 28

• treat the underlying cause (usually infection)
• bed rest, supportive bandages & anti-inflammatory medicine
• normally subsides in 3-6 weeks

Question 29

What is pyoderma gangrenosum and who is most commonly affected?

Answer 29

it is part of a group of auto-inflammatory diseases called neutrophilic dermatoses

this involves an excessive immune response due to a neutrophil dysfunction

it is uncommon and mainly affects over-50s

Question 30

What conditions is pyoderma gangrenosum thought to be linked to?

Answer 30

it is thought to sometimes be a reaction to a disease, such as:

• inflammatory bowel disease
• rheumatoid arthritis
• myeloid blood disorders (leukaemia)
• PAPA syndrome

50% of those affected do not have these risk factors

Question 31

What does pyoderma gangrenosum look like?

How long does it take to heal?

Answer 31

• fast-growing, highly painful ulcer (usually full thickness)
• ulcer has purple undermined borders
• may be multiple ulcers
• ulcer often starts at the site of injury
• complete healing may take months and will leave scars

Question 32

What are the treatments for pyoderma gangrenosum?

Answer 32

treatment is non-surgical

• removal of necrotic tissue and provision of expert wound care
• steroids are given topically or systemically depending on the size / spread of ulcers

Question 33

Why are antibiotics and surgical debridement not used to treat pyoderma gangrenosum?

Answer 33

• surgical debridement when ulcers are active may lead to increased ulcer size
• antibiotics are not useful unless there is a secondary infection