PIH

Question 1

Clinical features?

Answer 1

Epidermal pigment: brown - dark brown colour, fades several months
Dermal PIH: grey-brown appearance, takes years to fade
worsen through sun exposure

Question 2

Cause?

Answer 2

over production of melanin due to triggers:
Inflammation skin conditions: post acne marks, eczema, psoriasis, insect bites, burns

Skin trauma or irritation: Aggressive skincare, wound, surgical scar, adverse reaction from laser

Sun exposure: lack of sun exposure after skin injury

Question 3

Why does it happen? (pathophysiology)

Answer 3

Epidermal pigment: Acne causes inflammation which stimulates melanocytes to produce more pigment (melanogenesis). Excessive accumulation in the keratinocytes in the epidermis causes PIH

Dermal pigment: Melanin deposition due to cutaneous injury or inflammation. This can cause:
Pendulous melanocytes: sit abnormally which melanocytes release pigment in the dermis

Inflammation triggers melanocyte (cells that produces pigment) activity

UV exposure: UV rays stimulates tyrosinase = worsening the PIH and making it last longer

Question 4

Treatment Plan?

Answer 4

Epidermal pigment
Protect
SPF 50+

Topical - Tyrosinase inhibitors
vitamin c, niacinamide, kojic acid, azelaic acid
retinol: increase cell turnover

Chemical Peels
Glycolic acid: pigment inhibitor and increase cells turnover

Epidermal and dermal
Laser/IPL
Q-switch nanosecond and picosecond laser toning
:(Nd:YAG): target deep pigment due to long wavelength while preserving surrounding tissues
pico: use more mechanical damage = less heat damage
nano: thermal damage

Question 5

Is PIH epiderma, mixed epidermal-dermal or dermal pigment?

Answer 5

Dermal pigment and mixed epidermal-dermal pigment