Hypopigmentation

• Age:

  • Pityriasis alba typically affects children
  • Pityriasis versicolour usually affects young adults
  • Vitiligo affects people of any age but commonly starts before the age of 30
• Distribution:

  • Pityriasis alba - head, neck and arms
  • Pityriasis versicolour - trunk
  • Vitiligo - face, genitalia, hands and feet and flexures
• Surface change:

  • Fine scale (elicited by scraping the skin with a scalpel) suggests pityriasis versicolor
  • Pityriasis alba has an eczematous surface appearance
• Post-inflammatory hypopigmentation:

  • Usually resolves spontaneously once the underlying condition has been successfully treated but may take several months
• Pityriasis versicolour:

  • Fungal infection - typically Malasseszia species
  • Causes flat, scaly, discolouration (hypopigmentation) of the skin
  • Trunk and limbs
  • Usually in young adults
  • Treatment = topical azole cream/shampoo (ketoconazole 2%) for 5 days
  • Systemic antifungals if extensive or does not respond to topical treatment
• Pityriasis alba:

  • Mild, superficial eczema
  • Scaly white patches typically on the cheeks, chin and arms
  • More obvious with a tan
  • Revolves spontaneously
  • Regular emollients will improve dryness
  • 1% hydrocortisone will reduce inflammation
• Halo naevus:

  • Ring of hypopigmentation around benign melanocytic naevus
  • Benign melanocytic naevus undergoing destruction by the immune system
  • Gradually returns to it's normal colour over months or years