Common dermatological infections

Question 1

2 year old child presents with cold symptoms and fever, followed by greyish sports appearing in the back of the mouth and in the last 24 hours a confluent erythmatous macular rash has developed over the whole body but began around the ears
Child is generally unwell and has not been immunised

Answer 1

Measles

• spots called Koplik spots 2-3 days after symptoms begin
• Rash 5-7 days after symptoms began
• treatment is supportive but this is a notifiable disease
• 30% of cases suffer complications - particularly dangerous for pregnant women - hence vaccinate

Question 2

Rubella virus can cause very mild symptoms and sometimes is asymptomatic so why vaccinate?

Answer 2

• Congenital Rubella syndrome
• high risk of miscarriage

Note: may see petechiae in the mouth of children with rubella - called Forchheimer sign

Question 3

What is the manifestation of parvovirus in children and adults?

Answer 3

Children - slapped cheek

Adults - can cause myelosupression, in sickle cell etc can cause aplastic crisis

Question 4

Hand foot and mouth is caused by what virus? Who does it affect?

Answer 4

Coxsackievirus
Common in under 5s - erythmatous sores on hands and feet and ulcers in mouth - may all become blistered and child may be generally unwell with this

Question 5

List some streptococcal skin infections

Answer 5

Impetigo

Erysipelas

Question 6

What is a classical presentation of mollusc up contagiosum?

Answer 6

Child 1-4 years
Small discrete round pink umbillicated papules
Develop over local area - commonly the armpit
Clusters of these may appear and disappear for 12-18 months but usually resolve in this time

(Can present as an Sexually acquired infection in adults - should consider GUM screen in this case)

Question 7

How is a cold sore (herpes 1) differentiated from Impetigo?

Answer 7

Cold sores - more vesicular, smaller area of skin affected

Impetigo - spreads more, crusted

Question 8

How is oral Herpes simplex 1 infection (cold sores) treated?

Answer 8

Healthy individuals with mild/moderate symptoms - conservative treatment with pain relief and OTC antiviral preparations and OTC topical analgesic/anaesthetics

Immunocompromised - consider prescribing oral aciclovir 200/400mg 5xdaily 5/7 or valaciclovir 1g TD 7/7

Treatment should be started in first 24 hours of onset as antivirals reduce viral replication and most of this occurs in first 24hours with viral infections

Question 9

What is the most common causative organism of Impetigo?

Answer 9

Staphylococcus aureus (skin commensals)

Question 10

How can Impetigo be treated?

Answer 10

Hygiene measures
Stay off work/school until all lesions are healed, dry and crusted over or 48 hours after commencing antibiotics
FOOD HANDLERS - required by law to inform employer immediately

Frusidic acid - narrow spectrum
- topical apply 3-4 times daily for 7/7

(Can also be used for Staph eye infections but apply BD)

Question 11

What is meant by a tinea infection?

Answer 11

Group of infections caused by a dematophyte (ringworm) fungus

Tinea followed by word describing where the infection is eg. Tinea capitis

Question 12

What is the treatment for tinea fungal infections?

Answer 12

Terbinafine cream +/- low dose topical corticosteroid eg. 1% hydrocortisone
If extensive - oral Terbinafine 250mg OD (variable amount of weeks depending where the infection is)

Question 13

What is tinea incognita?

Answer 13

Fungal infection that has been misdiagnosed as dermatitis - GP may have prescribed steroid cream - this has masked the inflammation and itching but has allowed the fungal infection to spread but it will now look atypical