Chronic rash

Question 1

Define seborrheic dermatitis

Answer 1

Commonly inflammatory skin condition which occurs in areas rich in sebaceous glands

Question 2

What is the aetiology of seborrheic dermatitis

Answer 2

Many factors involved:
Malassezia furfur (yeast) presence
Underlying: HIV, genetic disorder e.g. Down’s
Boys > girls
Peak incidence <3 months of life

Question 3

What are the clinical features of infantile seborrhoeic dermatitis

Answer 3

Well-fined erythematous rash and scaling with tiny vesicles- commonly on the scalp (cradle cap)
→ face → behind the ears → flexures and napkin area
- Scales: yellow-brown, large, greasy
- Symmetrical distrubution
- Mild pruritus, infant otherwise unaffected and sleeps/feeds well

Question 4

What is the management for infantile seborrhoeic dermatitis

Answer 4

Re-assure, common and not serious. Will resolve over weeks/months spontaneously
Advice:
- Regular washing with baby shampoo → gentle brushing with soft brush → loosen scales
- Soften scales with baby oil → gentle brushing
- Soak crust overnight with whit petroleum jelly or slightly warmed vegetable/olive oil
- emulsifying ointment
- Non-face areas: bathe at least one a day using emollients, avoid soaps/detergents, frequent nappy change, zinc and castor oil ointment use
- Safety net
Second line: topical imidazole cream e.g. clotrimazole, miconazole

> 4 weeks → consider specialist advice, may use mild topical steroids

Question 5

What are the clinical features of adolescent seborrheic dermatitis

Answer 5

Well-defined patched of erythema and flaking of the skin
- Scales: white/yellow, oily or dry
- Symmetrical
- Mild pruritus
- Scalp (most common) → dandruff
- Face, eyes, upper cheek and back - May be petaloid type or pityriasiform type

Question 6

What is the management for adolescent seborrheic dermatitis

Answer 6

First line: ketoconazole 2% shampoo >12yo, selenium sulphide shampoo, zinc shampoo, coal tar, salicylic acid

For face/body: topical imidazole cream for up to 4 weeks and consider topical steroid

Question 7

What is the aetiology of acne

Answer 7

Follicular hyperkeratinisation
Hormonal influence on sebum production and composition (androgenic stimulation of the sebaceous glands → increased sebum excretion rate → sebum flow obstruction)
Inflammation, in part mediated by proprionibacterium acnes

Question 8

What are the causes of acne

Answer 8

Occupational, acne cosmetica, pomade: exposure to insoluble, follicle-occluding substances e.g. cutting oils, petroleum-based products, coal tar, aromatic hydrocarbons
Chloracne: hydrocarbon exposure
Mechanica: repeated mechanical and frictional obstriction e.g. helmets, chin straps, suspenders, collars, prosthesis, violin
Tropical: extreme heat
Radiation: post radiation dermatitis

Question 9

What are the types of acne

Answer 9

Open comedones (blackheads)
Closed comedones (white heads)
Papules
Pustules
Nodules
Cysts

Question 10

How is acne graded

Answer 10

Mild: <20 comedones, <15 inflammatory lesions
Moderate: 20-100 comedones, 15-50 inflammatory lesions
Severe acne: >5 pseudocysts, comedone count >100, total inflammatory lesions >50

Question 11

What is the management for mild acne

Answer 11

Advice
First line: topical treatment
- Benzoyl peroxide + clindamycin (Duac)
- Comedones → topical retinoids (adapalene)
- Pustular → topical retinoid ± topical Abx

Second line: alternative topical retinoid, azelaic acid, salicylic acid

Question 12

What is the management for moderate acne

Answer 12

Advice, try mild acne treatment
First line: PO Abx e.g. lymecycline, doxycyline (MAX 3 months) AND BPO or adapalene
Second line (scarring or not responding after 2 courses) → refer to dermatology → isotretinoin (Roaccutane)

IMPORTANT: A topical retinoid or benzyol peroxide should always be co-prescribed with PO antibiotics to reduce the risk of antibiotic resistance developing

Question 13

What are the side effects of isotretinoin

Answer 13

teratogenic → must be on 2 forms of contraception (barrier and hormonal) + regular pregnancy tests (once a month)
Dryness, pruritus, conjunctivitis, muscle aches, photosensitivity, teratogenic, deranged LFTs
Low mood and suicidal ideation

Question 14

What is acne fulminans

Answer 14

Most severe form
Abrupt development of nodular and suppurative acne lesions in association with systemic manifestations
Osteolytic bone lesions
Fever
Arthralgia, myalgia
Hepatosplenomegaly
Severe malaise
± erythema nodosum