Acne, Eczema, Erythema Infectosum

Question 1

What is Acne?

Answer 1

Acne vulgaris is a skin disease affecting the pilosebaceous unit. It is clinically characterised by comedones, papules, pustules, nodules, cysts, and/or scarring, primarily on the face and trunk.

Question 2

What is the epidemiology of Acne?

Answer 2

85% of people between 12-24 (US)

8% of adults

Question 3

What is the aetiology of Acne?

Answer 3

Androgens (higher in puberty) cause sebaceous gland hyperplasia and excess sebum production.

Kertinocytes accumulate abnormally and host cutibacterium acnes which causes an immune response and inflammation.

This is acne.

Question 4

What would you find in the history and exam of someone with acne?

Answer 4

Skin lesions
Tenderness
Hyperpigmentation and scarring

Question 5

What investigations would you do for acne?

Answer 5

Clinical diagnosis
Blood hormones
Bacterial culture if suspicious of other aetiologies

Question 6

What is the management of acne?

Answer 6

Topical retinoid (tretinoin) or salicylic acid
Topical dapsone (second line)
Diet and lifestyle advice

Question 7

What are the complications and prognosis of Acne?

Answer 7

Scarring, dyspigmentation

Goes down after adolescence- no real long term consequences

Question 8

What is eczema?

Answer 8

An inflammatory skin condition characterised by dry, pruritic skin with a chronic relapsing course

Question 9

What is the epidemiology of eczema?

Answer 9

Most commonly diagnosed before age 5

Onset most commonly in first year of life but not usually in first 2 months (like
infantile seborrheic dermatitis)

Resolves in 50% by age 12 and in 75% by age 16

Affects 10-20% of children

Question 10

What may you find in the history a child with eczema?

Answer 10

Other atopy
Family history
1/3 of children with eczema will develop asthma

Question 11

What are the causes of an eczema exacerbation?

Answer 11

Bacterial infection e.g. Staphylococcus, Streptococcus
o Viral infection e.g. HSV
o Ingestion of an allergen e.g. egg
o Contact with an irritant or allergen
o Environment: heat, humidity
o Change/reduction in medication
o Psychological stress
o Unexplained

Question 12

What are the complications of eczema?

Answer 12

Inflammation increases the avidity of skin for S aureus and reduces expression of
antimicrobial peptides → S aureus thrives on atopic skin and release superantigens which can maintain and worsen eczema

HSV can spread on eczema skin causing an extensive vesicular reaction, eczema
herpeticum

Regional lymphadenopathy is common and marked in active eczema – resolves when skin improves

Question 13

What are the clinical features of eczema?

Answer 13

• Pruritus
• Dry skin
• Distribution changes with age
o Infants: face and trunk
o Young children: extensor surfaces
o Older children: flexor surfaces
• Affected skin is erythematous, oedematous with prominent weeping and crusting
• Over time, prolonged scratching can lead to lichenification (accentuation of normal skin
markings)

Question 14

What investigations do you do for eczema?

Answer 14

• Clinical diagnosis

• If disease is severe, atypical or associated with unusual infections/faltering growth → exclude
an immune deficiency disorder

Question 15

How do you assess eczema severity?

Answer 15

o CLEAR - normal skin with no evidence of active eczema
o MILD - areas of dry skin and infrequent itching
o MODERATE - areas of dry skin, frequent itching and redness (with/without excoriation and localised skin thickening)
o SEVERE - widespread areas of dry skin, incessant itching and redness (with/without excoriation and localised skin thickening)
o INFECTED - eczema is weeping, crusting or there are pustules with fever and malaise

Consider using questionnaires such as the Children's Dermatology Life
Quality Index (CDLQI)

Question 16

How do you treat mild eczema?

Answer 16

Prescribe generous amounts of emollients and recommend frequent and liberal use
o Consider prescribing a mild corticosteroid (e.g. hydrocortisone 1%) for areas of red skin
▪ This should be continued for 48 hours after the flare has been controlled
o Routine follow-up is not normally necessary
o Refer for a routine dermatology appointment if the diagnosis is uncertain, current management has failed to control eczema, there is facial eczema or there is a recurrent secondary infection

Question 17

How do you treat moderate eczema?

Answer 17

o Prescribe a moderately potent topical steroid: betamethasone valerate
0.025% or clobetasone butyrate 0.05%
o Treatment should be continued for 48 hours after the flare has been controlled
o If there is severe itching or urticaria, consider prescribing a 1-month trial of a nonsedating antihistamine (e.g. cetirizine, loratidine, fexofenadine)
o Consider prescribing a maintenance regimen of topical corticosteroids to control areas of skin prone to frequent flares (not face, genitals or axillae)
o 2nd line: topical calcineurin inhibitors (e.g. tacrolimus) - only prescribed by a specialist
o Review regularly if the child is young and using a large amount of topical corticosteroids

Question 18

How do you treat severe eczema?

Answer 18

o Prescribe a potent corticosteroid: betamethasone valerate 0.1% to be used on inflamed areas
▪ For delicate areas of inflamed skin (e.g. face and flexures) use a moderate potency steroid
o Occlusive dressings or dry bandages may be useful
▪ These are helpful over limbs when scratching is a problem
▪ Can be impregnated with zinc paste
▪ Worn overnight
o Consider non-sedating antihistamine if there is severe itching
o If the itching is affecting sleep, consider using a sedating antihistamine (e.g. chlorphenamine)
o If there is SEVERE, extensive eczema causing psychological distress, consider a course of oral corticosteroids
o Prescribe a maintenance regimen of topical corticosteroids

Question 19

How do you treat infected eczema?

Answer 19

o Swab the infected skin
o 1st line: flucloxacillin
▪ If penicillin allergy: erythromycin (or clarithromycin)
▪ If Strep pyogenes: phenoxymethylpenicillin
o If the area of infection is localised, topical antibiotics should be effective
o NOTE: these should NOT be used for longer than 2 weeks

Question 20

What is erythema infectiosium?

Answer 20

Human Parvovirus B19 - slapped cheek syndrome

Happens in spring

Transmission via respiratory secretions, vertical transmission or blood products

Question 21

What is the aetiology of parvovirus B19 (erythema infectiosium)?

Answer 21

• HPV-B19 infects the erythroblastoid red cell precursors in the bone marrow
• It causes a range of clinical pictures

Question 22

What are the clinical features of parvovirus B19?

Answer 22

• HPV-B19 can cause a range of clinical syndromes

o Asymptomatic infection
▪ Common
▪ 5-10% preschool children have antibodies

o Erythema infectiosum: most common
▪ Viraemic phase of fever, malaise, headache and myalgia
▪ This is followed by a characteristic rash on the face
▪ This rash progresses to a maculopapular, ‘lace’-like rash on the trunk
and limbs
▪ In children, complications are rare. In adults, arthralgia and arthritis are
relatively common

o Aplastic crisis: most serious
▪ In children with chronic haemolytic anaemias where there is increased
RBC turnover e.g. SCD, thalassemia
▪ Also in immunocompromised children who are unable to produce an
antibody response to neutralise the infectious agent

o Fetal disease
▪ Transmission of maternal HPV-B19 infection may lead to fetal
hydrops and death due to severe anaemia, but majority of infected
foetuses will recover

Question 23

What investgations do you do for erythema infectiosium (HPV B19)?

Answer 23

This is a clinical diagnosis via typical slapped-cheek rash with a lacy, reticular exanthem on extremities and torso seen on examination

Question 24

What is the managment of HPV B19 erythema infectiosium?

Answer 24

• Management is supportive using paracetamol and ibuprofen, and encouraging adequate fluid intake
• Secondary arthritis may be treated with ibuprofen