Shingles, acne, and impetigo Flashcards
What infection causes chicken pox?
Varicella zoster virus
Describe the presentation of chickenpox
A contagious febrile illness with crops of blisters
What is the duration of the infectious period of chickenpox?
4 days before rash begins until all lesions are scabbed (~1 week)
State some complications of chickenpox
Purpura fulminans (acute thrombotic disorder of skin, leads to rapid skin necrosis and DIC) DIC Pneumonitis Ataxia
Which patients are more likely to experience complications of chickenpox?
Pregnant Adults
Explain the pathophysiology of shingles
Reactivation of varicella zoster virus in the dorsal root ganglia
Describe the characteristic features of shingles
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.
Name 4 complications of shingles
Post-herpetic neuralgia Secondary infection Scarring Ocular complications
What is post-herpetic neuralgia?
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
What treatment options exist for post-herpetic neuralgia?
Amitriptyline Topical lidocaine Gabapentine +- carbamazepine Phenytoin Last resort: ganglion ablation Refer to pain clinic
How can post-herpetic neuralgia be prevented? Which group is offered this option?
Herpes zoster vaccine: prevents PHN in 60% Provided to >60yr
What is the prognosis of shingles?
Typically self-resolves in 2-4 weeks
What are the treatment options for shingles?
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
How long is shingles contagious for? What advise should be given whilst contagious?
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.
What is acne vulgaris?
An inflammatory disease of the pilsebaceous follicle
What patients are most commonly acted by acne?
Teenagers aged 13-18 (80%)
State the causes of acne
Hormonal (androgens) Increased sebum production Abnormal follicular keratinisation Bacterial colonisation Inflammation
Which bacterium is associated with acne?
Propionibacterium acnes
How does mild acne present?
Non-inflammatory lesions Open and closed comedones (black and white heads)
How does moderate-severe acne present?
Inflammatory lesions Papules, pustules, nodules, cysts
Outline management of acne
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)
What are some complications of acne?
Post-inflammatory hyperpigmentation Scarring Deformity Psychological and social effects
Define impetigo
A common acute superficial bacterial skin infection, characterised by pustules and honey-coloured crusted erosions (school sores)
What are the commonest causes of impetigo?
Staph aureus Non-bullous: Group A haemolytic streptococcus e.g. Strep pyogenes
Describe the clinical features of impetigo
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
