Dermatology

Question 1

Psoriasis: nail changes

Answer 1

POSH*:

Pitting

Onycholysis

Subungal Hyperkeratosis

*remember you did your derm at CWH

Question 2

Which conditions show Koebner phenomenon? What is it?

Answer 2

Vitiligo

Psoriasis

Lichen planus

Warts

(Mirza)

The Koebner phenomenon describes the appearance of new skin lesions on areas of cutaneous injury in otherwise healthy skin. It is also known as the isomorphic response. (DermNet)

Question 3

Outline the mx for impetigo

Answer 3

Limited, localised disease

• topical fusidic acid is first-line
• topical retapamulin is used second-line if fusidic acid has been ineffective or is not tolerated
• MRSA is not susceptible to either fusidic acid or retapamulin. Topical mupirocin (Bactroban) should therefore be used in this situation

Extensive disease

• oral flucloxacillin
• oral erythromycin if penicillin allergic

Question 4

Define melanoma

Answer 4

Uncontrolled growth of melanocytes, potentially developing into a serious type of skin cancer

Confined to epidermis = melanoma in situ

Spread to dermis = invasive melanoma

Spread to other tissues = malignant melanoma

(DermNet)

Question 5

Give RFs for melanoma

Answer 5

RFs:

• Increasing age
• Previous melanoma / BCC / SCC
• Multiple benign melanocytic naevi (moles)
• >5 atypical moles
• FHx moles
• Pale skin

(DermNet)

Question 6

What features characterise melanoma?

Answer 6

The ABCDEs of Melanoma

• Asymmetry
• Border irregularity
• Colour variation
• Diameter >6mm
• Evolving (enlarging, changing)

(DermNet)

Question 7

Summarise the prognosis for patients with melanoma

Answer 7

Most important prognostic factor is Breslow thickness (between top of epidermis and bottom of tumour):

• Stage 1: <0.75mm
• Stage 2: 0.76 - 1.5mm
• Stage 3: 1.5 - 2.25mm
• Stage 4: 2.25 - 3.0mm
• Stage 5: >3mm

Metastasis: <1mm = 5% risk, >4mm= 40% risk of metastasis

Recurrence: melanoma in situ in 20%, invasive melanoma in 5-10%

(DermNet, Path)

Question 8

Generate a management plan for melanoma

Answer 8

Surgical

• Diagnostic excision, 2-3mm margin
• Followed by wide local excision if dx of melanoma is made. Thickness depends on stage of melanoma (5-20mm)
  
  • • sentinel node biopsy or excision of enlarged nodes
  • • adjuvant chemotherapy if malignant melanoma
      
      • IL2, IFNalpha2b
      • Imatinib, pembrolizumab, nivolumab
• R/v at least every 6m to check for recurrence (DermNet)

Question 9

Generate a management plan for acne rosacea

Answer 9

Acne rosacea treatment:

• Medical
  
  • antibiotics:
    
    • mild/moderate: topical metronidazole
    • severe/resistant: oral tetracycline
  • 2nd line: isotretinoin (13cis-retinoic acid). Bad SEs
• conservative:
  
  • camouflage creams may help conceal redness
  • laser therapy for patients with prominent telangiectasia
  • recommend daily application of a high-factor sunscreen

NB: never give steroids, worsens it in long term

(passmedicine, dermnet)

Question 10

Generate a management plan for chronic psoriasis

Answer 10

Chronic

• Conservative
  
  • RF modification: reduce triggers (smoking, stress, ETOH, sun, obesity)
• Medical - primary care
  
  • Regular emollients
  • 1st line: topical corticosteroid + topical vitD analogue eg calcipotriol (applied separately, one in the morning and the other in the evening, 4 weeks as initial treatment)
  • 2nd line: if no improvement after 8 weeks then vitD analogue BD
  • 3rd line: if no improvement after 8-12 weeks then either:
    
    • potent corticosteroid BD for up to 4 weeks or
    • coal tar preparation applied once or twice daily
• Secondary care management
  
  • Phototherapy: narrow band ultraviolet B light, 3/w
  • Systemic therapy
    
    • 1st line: oral methotrexate, esp if associated joint disease
    • ciclosporin
    • systemic retinoids
    • biological agents: infliximab, etanercept and adalimumab

(passmedicine, NICE)

Question 11

Generate a management plan for acne vulgaris

Answer 11

Acne vulgaris treatment:

• Medical
  
  • 1st (mild): topical retinoids or topical benzoyl peroxide
  • 2nd: topical combination therapy (antibiotic, benzoyl peroxide, retinoid)
  • 3rd (moderate): oral antibiotics: e.g. Oxytetracycline, doxycycline. Improvement may not be seen for 3-4 months.
    
    • Gram negative folliculitis may occur as a complication of long-term antibiotic use - high-dose oral trimethoprim is effective if this occurs
    • +/- antiandrogen medication (eg COCP)
• 4th (severe): oral isotretinoin: only under specialist supervision

(passmedicine, DermNet)

Question 12

Summarise the epidemiology of psoriasis

Answer 12

M=F

Onset 15-25 and 50-60 (bimodal)

Caucasians especially

(DermNet)

Question 13

Give causes of erythema multiforme

Answer 13

• Post-HSV infection: most common, 7-14d post infection
• Other infections: mycoplasma, TB, strep
• Drugs: sulphonamides, sulphonylureas, carbemazepine

(Meeran)

Question 14

How do you examine a skin lump?

Answer 14

4S 4C 4T

• Site
• Size
• Shape
• Surface
• Colour
• Consistency
• Contour
• Cough impulse
• Tenderness
• Temperature
• Transilluminance
• Tethering

(AS)