Dermatology

Question 1

Infantile Acne (key point, presentation, differentials, prognosis, treatment options)

Answer 1

Key point: comedones must be present.
Presentation: after 3 months of age with comedones, papules and pustules.
Differentials: milia, miliaria, neonatal cephalic pustulosis.
Prognosis: Mild cases resolve by the age of 12 months. Large comedones can leave permanent pits.
Treatment options:
● Mild - benzoyl peroxide 5% gel topically daily
● Large and numerous with minimal inflammation - adapalene 0.1% topically nocte
● Large and numerous with inflammation - epiduo 0.1%/2.5% daily

Question 2

Acne - adolescent or adult

flowchart, antibiotics, when to refer

Answer 2

Flowchart
● All - OTC benzoyl peroxide 5%
● Comedonal and minimal inflammation - topical retinoid
● Comedones and inflammatory papules/pustules - benzoyl peroxide and retinoid (more comedones) benzoyl and antibiotic (more inflammatory)
* Refer to page 37 in GP Study Notes
Antibiotics
Moderate to severe acne in adolescents and adults
● Doxycycline 50 to 100mg PO daily for 6 weeks and then review
● If above contraindicated: erythromycin 250 to 500 g PO BD for 6 weeks and then review
Refer
Refer patient to dermatologist for oral isotretinoin if:
● Treatment is not sufficiently effective or tolerated
● The acne is severe
● The acne is having an impact on emotional and social wellbeing

Question 3

Blepharitis (definition, association, types, management)

Answer 3

Definition: Chronic inflammatory condition of the eyelid margins.
Associated with: Seborrhoeic dermatitis, acne, rosacea and dry eyes.
Types:
Anterior Inflammation of the anterior eyelid margin involving the eyelid skin and eyelashes.
Presents with burning and grittiness.
Examination shows crusting, scaling and redness of the eyelid margin.
Posterior Dysfunction of the meibomian glands.
Associated with rosacea.
Signs include redness of the eyelid margin with blocked meibomian glands and a frothy
discharge along the eyelid margins +/- associated chalazia.
Management:
1. Eyelid hygiene daily
● Warm compresses
● Gentle scrubbing of the lashes
2. Chloramphenicol 1% BD for 1-2 weeks (** for anterior blepharitis if not controlled with eyelid hygiene)
3. Doxycycline 100mg PO daily (** for posterior blepharitis if associated with rosacea)

Question 4

Calcaneal petechiae (talon noir)
(cause, test)

Answer 4

Cause: dried erythrocytes after trauma.
Distinguishing factor from warts: skin lines not disrupted.
Test: scraping with scalpel.

Question 5

Image reviews - Nodular melanoma, sebaceous hyperplasia, nodular BCC, keratosis pilaris

Answer 5

** Refer to page 118 - 120 of GP Study Notes

Question 6

Eczema (non-pharmacological management)

Answer 6

Non-pharmacological management:
● Regular use of emollients
● Minimise contact with irritants such as bubble bath, wool and dust
● Add the oil to the bathwater
● Use lukewarm water for bathing
● Use soap substitutes
● Use wet dressing for severe flare ups
● Bleach bath for recurrent infections

Question 7

Nodal melanoma (key point, local excision margins)

Answer 7

Key point
● Nodal metastasis is metastatic melanoma involving the lymph nodes
● Can proliferate in any tissue but most often grows in the lungs, in or under the skin, the liver and brain

Local excision margins

• in situ: 5mm
• thinner than 1mm: 1cm
• 1 to 4mm thick: 1-2cm
• thicker than 4mm: 2cm

Question 8

56M, presenting for the result of an excisional biopsy from a pigmented lesion you removed with 2mm margin from his L) thigh last week. Report is as below: The excised skin demonstrates epidermal ulceration overlying a collection of irregular melanocytes. There is pagetoid spread of melanocytes into the epidermis. Multiple bizarre nuclei are appreciated. There are nests of severely atypical melanocytes extending down into the dermis without normal maturation. The distance between the upper layer of the epidermis and the deepest point of atypical cells is 1.2mm with mitosis rate of 5 per square millimetre. The margins are clear of atypical cells.

1. What is your next single step in his management?
2. Joseph returns to see you 12 months later with an enlarged lymph node or 21mm in his left groin. What investigations would you choose as part of the initial assessment?

Answer 8

What is your next single step in his management?
● Early referral to melanoma clinic
Joseph returns to see you 12 months later with an enlarged lymph node or 21mm in his left groin. What investigations
would you choose as part of the initial assessment?
● Abdominal CT
● Chest XR
● Excisional biopsy of lymph node

Question 9

Tinea cruris (key points, appearance, diagnosis, treatment)

Answer 9

Key points:
1. AKA Jock itch
2. Can be confused with intertrigo (rash secondary to friction between adjacent skin sites)
3. How itchy: very!
Appearance
● Similar to tinea corporis (ringworm)
● Scaly raised red border
Diagnosis: confirmed by skin scraping MCS
Treatment: topical antifungal +/- hydrocortisone. If unsuccessful, terbinafine or itraconazole.