Shingles, acne, and impetigo

Question 1

What infection causes chicken pox?

Answer 1

Varicella zoster virus

Question 2

Describe the presentation of chickenpox

Answer 2

A contagious febrile illness with crops of blisters

Question 3

What is the duration of the infectious period of chickenpox?

Answer 3

4 days before rash begins until all lesions are scabbed (~1 week)

Question 4

State some complications of chickenpox

Answer 4

Purpura fulminans (acute thrombotic disorder of skin, leads to rapid skin necrosis and DIC) DIC Pneumonitis Ataxia

Question 5

Which patients are more likely to experience complications of chickenpox?

Answer 5

Pregnant Adults

Question 6

Explain the pathophysiology of shingles

Answer 6

Reactivation of varicella zoster virus in the dorsal root ganglia

Question 7

Describe the characteristic features of shingles

Answer 7

Unilateral itchy crusting rash across a dermatomal distribution Highly contagious Intense neuralgic pain, especially in trigeminal nerve involvement. Prodromal abnormal sensation over affected area, headaches, malaise, fever.

Question 8

Name 4 complications of shingles

Answer 8

Post-herpetic neuralgia Secondary infection Scarring Ocular complications

Question 9

What is post-herpetic neuralgia?

Answer 9

Chronic debilitating pain following shingles Constant or intermittent stabbing/burning pain Allodynia (pain from non-painful stimuli) Hyperalgesia (severe pain from mildly-painful stimuli) Intense itching

Question 10

What treatment options exist for post-herpetic neuralgia?

Answer 10

Amitriptyline Topical lidocaine Gabapentine +- carbamazepine Phenytoin Last resort: ganglion ablation Refer to pain clinic

Question 11

How can post-herpetic neuralgia be prevented? Which group is offered this option?

Answer 11

Herpes zoster vaccine: prevents PHN in 60% Provided to >60yr

Question 12

What is the prognosis of shingles?

Answer 12

Typically self-resolves in 2-4 weeks

Question 13

What are the treatment options for shingles?

Answer 13

Calamine lotion to relieve itching Antiviral treatment (aciclovir) within 72hr of rash onset. Paracetamol, co-codamol, or NSAIDs for pain Gabapentine or pregablin for severe pain

Question 14

How long is shingles contagious for? What advise should be given whilst contagious?

Answer 14

Shingles rashes are contagious when weeping. Stops being contagious after all rashes have crusted (7-10 days). Patients should avoid contact with patients who have not had chickenpox. Avoid work, school, or daycare if the weeping rashes cannot be covered.

Question 15

What is acne vulgaris?

Answer 15

An inflammatory disease of the pilsebaceous follicle

Question 16

What patients are most commonly acted by acne?

Answer 16

Teenagers aged 13-18 (80%)

Question 17

State the causes of acne

Answer 17

Hormonal (androgens) Increased sebum production Abnormal follicular keratinisation Bacterial colonisation Inflammation

Question 18

Which bacterium is associated with acne?

Answer 18

Propionibacterium acnes

Question 19

How does mild acne present?

Answer 19

Non-inflammatory lesions Open and closed comedones (black and white heads)

Question 20

How does moderate-severe acne present?

Answer 20

Inflammatory lesions Papules, pustules, nodules, cysts

Question 21

Outline management of acne

Answer 21

Treatment must be continued for at least 6 weeks to see effect Mild acne: topical therapies of benzoyl peroxide and antibiotics, topical retinoids (Vitamin A) Moderate-severe acne: oral antibiotics, oral anti-androgens (in females) Severe acne: oral retinoids (e.g. Accutane)

Question 22

What are some complications of acne?

Answer 22

Post-inflammatory hyperpigmentation Scarring Deformity Psychological and social effects

Question 23

Define impetigo

Answer 23

A common acute superficial bacterial skin infection, characterised by pustules and honey-coloured crusted erosions (school sores)

Question 24

What are the commonest causes of impetigo?

Answer 24

Staph aureus Non-bullous: Group A haemolytic streptococcus e.g. Strep pyogenes

Question 25

Describe the clinical features of impetigo

Answer 25

Mainly affects exposed areas such as the face and hands Single or multiple Irregular crops of irritable superficial plaques Lymphadenopathy, mild fever, and malaise may occur