Ch 3.3 - Cold Sores & Scabies

Question 1

Name the virus responsible for cold sores / herpes labialis

and which one typically infects the lips?

Answer 1

herpes simplex virus (HSV) of which there are two major types:
HSV1 and HSV2.

herpes simplex virus (HSV) of which there are two major types:
HSV1 and HSV2.

Question 2

How do cold sores occur?

Answer 2

Initial infection usual at young age. The virus is not completely eradicated and virus particles lie dormant in nerve roots until they are reactivated later.

Question 3

Describe the symptoms and timeline of cold sores

Answer 3

Discomfort, tingling or irritation (prodromal phase) may occur in the skin 6-24 hours before appearance.

Begins with minute blisters on top of inflamed, red, raised skin. Maybe filled with white matter.

Quickly break down to show raw area and crusts by 4th day.

About 1 week - most lesions healed

Extremely painful - critical to distinguish from mouth cancer

Question 4

What are the precipitating factors of cold sores?

Answer 4

Sunlight
Wind
Fever (during infections & colds)
Menstruation 
Being rundown 
Local trauma to skin
Physical/Emotional stress

Question 5

When should you refer patients with cold sores?

Answer 5

1. Babies and young children
2. Failure of a sore to resolve
3. Severe or worsening sore
4. History of freq. sores
5. Lasting longer than 2 weeks
6. Painless sore
7. Patients with atopic eczema
8. Eye affected
9. Uncertain diagnosis
10. Immunocompromised patient

Question 6

What can be used to treat a cold sore?

Answer 6

1. Aciclovir (antiviral) - reduces healing time and pain
   Treatment should be started asap before lesion appears (most effective).
2. Antiseptics

Complementary therapies: tea tree oil & balm mint extract

Question 7

How often should Aciclovir be used?

Answer 7

5 times a day up to 5 days.

Question 8

What are some practical points to prevent cold sores?

Answer 8

Preventing cross infection - HSV1 is contagious and transmitted by direct contact.

Use of sunscreen

Sources of stress identified

Question 9

What is scabies?

Answer 9

Infestation by the scabies mite (Sarcoptes Scabei)

Question 10

What are the symptoms of scabies?

Answer 10

Causes an allergic reaction - Intense itching especially at night

Burrows can be seen like small thread-like grey lines. Lines are raised, wavy and 5-10mm long.

Rash - but not always at the site of infestation

Question 11

Where do you usually find the burrows of scabies?

Answer 11

Web spaces of hands and toes, wrists, armpits, buttocks and genital area

In adults - rarely affects the scalp and face but in children aged 2 or under and elderly, the head is more common

Question 12

How long does it take for an itch to develop in someone who has not been infested before?

Answer 12

6-8 weeks

Scabies mite transmitted by close personal contact - so ask patient if any close family/friends/boy/girlfriends have the same symptoms

Question 13

What can scratching lead to in scabies?

Answer 13

Leads to excoriation = secondary infection such as impetigo can occur

presence of yellow discharge or crusts = referral

Question 14

When should you refer patients with scabies?

Answer 14

1. Babies and scabies
2. Infected skin
3. Treatment failure
4. Unclear diagnosis

Question 15

Treatment for scabies?

Answer 15

1. Permethrin cream
2. Malathion used if above not suitable

Two treatments recommended - 7 days apart

Question 16

How would you counsel a patient on how Permethrin cream is to be used?

Answer 16

30-60g for single application in an adult. Treatment applied to the whole body, neckwards down (but not neck, face and scalp in adults)

Preparation should be emptied in a bowel, and using a paintbrush or cotton wool, it should be applied to clean, dry skin all over the body as directed. Ensure webs of fingers, fingernails and toenails are covered too.

Left for 8-12 hours

Question 17

How would you counsel a patient on Malathion?

Answer 17

for 1 adult - 100ml should be sufficient.

Applied to the whole body omitting the head and neck. Lotion should be left on for 24 hrs, without bathing, after which should be washed off.

If hands washed during the 24 hours - it should be reapplied to hands.

Question 18

Itch will continue after treatment with scabies creams - what can be advised?

Answer 18

Crotamiton cream/lotion could be used to relieve symptoms if skin is not badly excoriated.

Oral antihistamines - promethazine if itch is severe

Question 19

What are some practical advice for scabies?

Answer 19

Apply cream at bedtime - leave to dry first.
apply to clean, cool and dry skin

All members of family/household should be treated on the same day

Bedclothes and clothing should be washed