What is ABNOM? What is the causes of ABNOM and what are the treatments available?

ABNOM is also very often mistaken for freckles.

But unlike freckles, ABNOM is slate-grey macules usually appear bilaterally at areas innervated by 1st and 2nd division of trigeminal nerve (V1,V2) on the face, whereas freckles appear as light brown small spots usually found over cheeks, nose, forehead, chin and neck.

ABNOM can occur simultaneously along with other pigmentation such as melasma and freckles. Accurate identification is important as different types of pigmentation will be treated using different light therapy wavelengths.

Risk factors of ABNOM

Gender. ABNOM are mostly found in females and can be rarely seen in male

Age. ABNOM starts to appear at age of 10-20s

What causes ABNOM?

These are some of the most common causes for ABNOM:

  • Genetic predisposition. Higher prevalence is noticed if 1st degree family member has the same pigmentation
  • Sunlight exposure. UV light will stimulate melanocyte in our skin to produce melanin
  • Some studies showed higher prevalence of developing ABNOM in those taking contraceptives and during pregnancy

How to diagnose ABNOM?

Most of the cases can be diagnosed based on history and clinical appearance

How to prevent ABNOM?

  • Sun protection. It plays a major role in preventing ABNOM. Sunscreen which can protect both UVA and UVB will be a good choice.
  • Hydration. Adequate skin hydration is essential as well to reduce risk of aggravating melanin.

What are the treatments available?

In terms of treatment, topical creams will not be effective as ABNOM developed in dermal layer. Thus, lasers have been introduced to treat ABNOM and shown effective outcome. The most commonly used lasers are 1064nm Q-switched neodymium: yttrium aluminium garnet (Nd: YAG) lasers, Q switched alexandrite laser (QSAL) and Q-switched ruby laser (QRSL).

  • Q-switched Nd:YAG lasers: Works by destroying dermal pigments. Multiple treatments are necessary in treating ABNOM depending on individuals and severity. Using the principle of selective photothermolysis, ABNOM has been successfully treated with Nd:YAG laser. With Nd: YAG laser, one can undergo treatment without experiencing any downtime, very much compatible with current lifestyle.

Temporarily PIH (Post inflammatory Hyperpigmentation) is sometimes observed at early stage of treatment which will settles over time.