Infections & Infestations

Question 1

Describe the progression of HSV? [3]

Answer 1

1st exposure causes the first clinical episode or goes straight to latency.

Lies latent in your DRG (dorsal root ganglion)

New episodes occur due to certain stimuli

Question 2

What can cause a flare up of HSV? [5]

Answer 2

• Trauma
• Menstruation
• Sunlight
• Fever
• Stress

Question 3

So if a patient presents with small closely grouped vesicles/pustules that come and go in the same place?

Answer 3

Herpes simplex virus

Tends to return to the same spot as the first exposure e.g. hands/genital/mouth

Question 4

How do we treat HSV?

Answer 4

Aciclovir

Question 5

What patients suffer particularly severe HSV infections? [2]

Answer 5

Immunocompromised or atopic patients

Question 6

How does Herpes Zoster Virus appear?

Answer 6

Closely grouped vesicles in a dermatomal distribution

Question 7

What conditions are caused by HZV? [2]

Answer 7

Chickenpox on primary exposure

Shingles later

Question 8

Complications of HZV [2]

Answer 8

Extensive Scarring and Post-herpetic Neuralgia

Question 9

If a patient tells you they had a small number of papules/vesicles on their hands and after 6 weeks broke out in itchy excoriations and pustules on their chest what do you think they have?

Answer 9

SCABIES!! Delayed type IV hypersensitivity to sarcoptes scapei

Female mite digs a burrow and lays eggs which hatch as larvae.

Question 10

How are Scabies transmitted? [2]

Answer 10

Person to person.

Its slow, you have to hold someones body for around a minute for the mites to pass over. (loved ones that share beds)

Question 11

What can you look for to confirm scabies? [3]

Answer 11

• Papules, vesicles, pustules and nodules affecting
• Fingers, wrist flexures, axillae, abdomen, buttocks and groins
• Characteristic wavy red or grey line where burrowed

Question 12

How do you treat scabies? [3]

Answer 12

1. Permethrin 5% cream
   - Patient has to cover their whole body in it, wash off after 24h, repeat in 1 week
2. Oral ivermectin if severe

Ensure you treat all their contacts simultaneously (household) to prevent re-infection

Question 13

What virus causes warts?
Incubation period?
Natural course?

Answer 13

Human Papilloma Virus (HPV)
has a 4 month incubation period
Usually regresses within months-2y

Question 14

What are the types of Warts? [4]

Answer 14

Common
Plantar
Genital
Other - Plane/filiform/mosaic

Question 15

How do you treat warts? [4]

Answer 15

• Largely let them regress themselves, intervene only if symptomatic
• Chemical paints e.g. salicylic acid
• Cryotherapy 3-4w weekly
• Imiquimod (genital warts)

Question 16

What are the main causative organisms for bacterial skin infections? [2]

Name 2 bacterial skin infections [2]

Answer 16

Staph Aureus
Streptococci

Erysipelas
Cellulitis

Question 17

How do we treat bacterial infections? [2]

Answer 17

Antibiotics - IV for Erysipelas

Drain pus from a boil

Question 18

Whats the most common fungal infection and how do you get it?

Answer 18

Candida Yeast

Wet, unclean areas like under breasts. nails or between fingers get infected if poor hygiene

Question 19

How does candida present and how do we get ris of it? [2]

Answer 19

Erythema rash with satellite pustules

Oral or topical antifungals (e.g. fluconazole)

Question 20

What infections can dermatophyte fungi cause? [4]

Answer 20

Tinea Pedia (Athlete’s Foot)
Tinea Corpuris
Tinea Cruris (akak Tinea Incognito)
Tinea Barbea

Question 21

Describe presentation of the following Tinea infections:
Tinea corpororis
Tinea crusis
Tinea pedis
Tinea manuum
Tinea capitis
Onychomycosis
Tinea incognito
Pirtyriasis versicolour

Answer 21

• Tinea corporis: itchy annular lesions of trunk and limbs with clearly defined raised and scaly edge
• Tinea crusis: itchy annual lesions of groin and natal cleft with clearly defined raised and scaly edge
• Tinea pedis (athlete’s foot): moist scaling and fissuring of toe webs, spreading to sole and dorsal aspect of foot, white flaky skin
• Tinea manuum: scaly and drying of palmar creases
• Tinea capitis: patches of broken hair, scaling and inflammation
• Onychomycosis: yellow discolouration, thickened and crumbly nail (usually due to Trichophyton rubum (dermatophyte))
• Tinea incognito: inappropriate treatment of tinea with topical or systemic corticosteroids causes ill-defined and less scaly lesions
• Pityriasis versicolour: pale brown patches on upper trunk that fail to tan on sun exposure

Question 22

How do we test for Tinea infection? [1]

Answer 22

Skin scrape from the edge of the scaly rings for a fungal culture

Question 23

What is Kerion?

Answer 23

A fungal scalp infection, mainly in kids whos scalps dont make much sebum (grease). Fungal causing abscess.

Question 24

How do we test for kerion?

Answer 24

Hair sample from affected area for a fungal culture

Question 25

What is erysipelas

Answer 25

Acute superficial infection of dermis and upper subcutaneous tissue