Dermatology

Question 1

What is the term for a rash (skin eruption) consisting of raised and flat lesions?

Answer 1

Maculopapular rash

Macules = flat lesions

Question 2

What are Koplik spots?

Answer 2

Pathognomic for measles and occur 1-2 days before rash onset Usually located near lower pre-molars
Spots are small greyish-white surrounded by an erythematous base

Question 3

What is the normal heart rate for a 4 year old?

Answer 3

110-160 bpm

Question 4

Child patient has red maculopapular rash (morbilliform rash) starting on neck and face and spreading onto trunk and limbs Unwell with high fever and has viral prodromal symptoms (malaise, rhinnorhoea, non-purulent conjunctivitis)
Also has Koplik spots which precede the rash. What is the likely diagnosis?

Answer 4

Measles

Question 5

What is the risk of catching measles if you have had the MMR vaccine?

Answer 5

Provides protection from measles in about 90% of its recipients

Question 6

How is measles spread? And how long is it infective for?

Answer 6

Airbourne or droplet transmission
Period of infectivity is from start of prodromal symptoms to about 4 days after rash onset and then incubation period of 8-14 days

Question 7

How do you manage a case of measles?

Answer 7

Supportive management: Keep patient hydrated and use anti-pyretics if patient unwell with the fever
Advice should be given both verbally and written. This should include keeping patient away from susceptible individuals until 5 days after rash onset
Advise on symptoms and signs to look out for indicating deterioration or developing complications
Send off saliva sample to laboratory to confirm diagnosis and report the case to the local public health agency. Measles is a notifiable condition

Question 8

What are some potential complications of measles? In which groups are these complications more likely?

Answer 8

Otitis media (7-9%)
Pneumonia (1-6%)
Diarrhoea (8%)
Convulsions (1/200)
Encephalitis (1/1,000) 
Subacute sclerosing panencephalitis
Death (1/5,000)
Complications are more severe and more likely in infants, 
immunocompromised and poorly nourished and chronically ill children

Question 9

5 year old girl with an itchy rash behind her knees and on both her wrists. She is well, she does not have a fever, her skin is noted to be dry and there are some excoriations. She has mild asthma for which she uses a salbutamol inhaler. What is the likely diagnosis?

Answer 9

Atopic eczema

Question 10

What blood test results might be noted in a patient with atopic eczema?

Answer 10

Serum IgE may be raised and there may be an eosinophilia

Question 11

What are excoriations?

Answer 11

Scratch marks/abrasions. Superficial breaks in the skin surface as a result of trauma such as scratching

Question 12

4 year old boy, brought in to GP by his mum. Not been himself over last 3 to 4 days which she thought was due to a cold as he had a runny nose and red eyes. Noticed he had some spots on his face yesterday and today his rash has become much more
widespread. Rash consists of both flat and raised skin lesions with lesions being less than 5mm in diameter. Some of the lesions have merged and become confluent. What is your differential diagnosis?

Answer 12

Viral exanthem: rubella, measles, scarlet fever, roseola infantum, erythema infectiosum/fifth disease
Drug eruption
Allergic reaction

Question 13

What signs would you look for to indicate skin infection?

Answer 13

Crusting, weeping, pustules, fever, tachycardia

Increased redness and heat to the skin

Question 14

If an eczematous rash is infected, what bacteria is the likely cause and what antibiotics would you prescribe?

Answer 14

Staphylococcus aureus
Group A Streptococcus
If no penicillin allergy, flucloxacillin would be first line

Question 15

What is lichenification and why does it occur?

Answer 15

Thickening of epidermis (with exaggeration of normal skin lines/markings)
Usually due to chronic rubbing/scratching. Skin is described as feeling leathery and is usually discoloured

Question 16

What is diprobase and what is its purpose?

Answer 16

Emollient cream to keep skin hydrated
Dry skin means barrier function has been impaired allowing allergens and irritants to penetrate it easier
Use emollients liberally, best applied when skin is wet following a shower/bath and should be used even when there is no sign of
eczema to prevent flare-ups

Question 17

What is hydrocortisone and how is it used in eczema?

Answer 17

Hydrocortisone 1% ointment is a topical corticosteroid
Purpose is to reduce inflammation
Potency and duration of treatment should be kept to minimum
Typically prescribed for 5-7 days
Management depends on severity of eczema, location of the rash, age of patient, previous treatment, presence of complications such as infection, psychosocial effects of rash eg not sleeping, poor self-esteem

Question 18

Why are we cautious when prescribing corticosteroids? Who is particularly susceptible to adverse effects?

Answer 18

Children and elderly especially susceptible to adverse effects because they have a thinner epidermis
Local adverse effects : Thinning of skin, striae, worsening and spreading of infection
Systemic adverse effects: growth retardation, Cushing’s syndrome, adrenal suppression

Question 19

Why is contact dermatitis different from eczema?

Answer 19

Eczema: widespread distribution

Contact dermatitis: localised and unusual distribution

Question 20

What is the underlying mechanism for contact dermatitis?

Answer 20

Chemically induced irritation (irritant eczema) or allergic sensitisation (type 4 hypersensitivity reaction to environmental chemical sensitisers)
Allergic sensitisation: at sites that make physical contact with eliciting sensitiser in those susceptible to developing an allergic reaction
Irritant eczema: after exposure (repeated) to an irritant and can occur in anybody. It does not have an immunological cause, the irritant itself causes inflammation through tissue damage

Question 21

What infectious agent causes chickenpox?

Answer 21

Herpes zoster - a DNA virus

Question 22

What type of lesion is seen in chickenpox?

Answer 22

Vesicles all over the body

Question 23

How do you manage a case of chickenpox?

Answer 23

Supportive treatment: Fluids, Paracetamol if symptomatic with fever, Anti-histamines and calamine lotion can be helpful for itch
Advice (e.g. regarding infectivity) and safety-netting

Question 24

What are risks to pregnant women with chickenpox exposure?

Answer 24

Need to know if they have previously had chickenpox or previously been checked for varicella antibodies
If they have no antibodies to VZ virus then she should be given varicella zoster immunoglobulin (VZIG)
Risk of congenital varicella syndrome (until 20 weeks gestation) which causes a range of problems including intrauterine growth restriction, microcephaly, limb hypoplasia, cataracts and cutaneous scarring. Infection at a later stage of pregnancy can cause premature delivery or neonatal chickenpox. The most severe chickenpox occurring if the infant is born within seven days of the onset of the mothers rash

Question 25

How do you distinguish between chickenpox and shingles?

Answer 25

Chickenpox rash is widespread, not dermatomal as in shingles
Shingles is rare in young children, chickenpox is common
Do other children have a similar rash?
You cannot catch shingles
Shingles is painful rather than itchy

Question 26

How is shingles transmitted?

Answer 26

You cannot catch shingles
A susceptible person can catch chickenpox from shingles, spread from fresh skin lesions – direct contact or airborne
Shingles arises from reactivation of varicella virus that is lying latent in the dorsal root and cranial nerve ganglia

Question 27

What does parvovirus B19 cause?

Answer 27

Slapped cheek syndrome (erythema infectiosum, fifth
disease)
Typically a mild viral illness which is followed by intense erythema on the cheeks and a reticulate (lace-like) erythema to trunk and limbs

Question 28

What is scarlet fever and what are its symptoms?

Answer 28

Red strawberry tongue (initially white strawberry tongue, white coated tongue with bright red papillae) and maculopapular rash (small red papules)
Rash tends to be generalised and have a sandpaper texture. It follows a streptococcal infection, usually pharyngitis

Question 29

How do you treat scarlet fever?

Answer 29

Penicillin

Question 30

What is Tinea corporis?

Answer 30

Ringworm of the body

Usually presents with asymmetrical scaly patches which show central clearing and an advancing scaly red edge

Question 31

How do you treat tinea corporis?

Answer 31

Topical antifungal cream

Question 32

What is erythema nodosum? What diseases is it associated with?

Answer 32

Inflammatory condition of adipose tissue under skin usually on shins
Associated with infection: streptococcal, TB, mycoplasma pneumoniae, EBV, cat scratch disease
Autoimmune disorders: IBD, Behçet’s disease, sarcoidosis
Pregnancy
Medications: sulfonamides, penicillin, oral contraceptives
Cancer: non Hodgkin’s lymphoma, carcinoid tumours, pancreatic cancer