Can Pico Laser Treat Deep Freckles, Nevus of Ota and Hori’s Nevus the Same Way?

The short answer is that Pico laser can be an option for dermal pigment such as nevus of Ota and Hori’s nevus, but they should not be treated with one fixed protocol. “Deep freckles” is a broad everyday term, not a single diagnosis, while nevus of Ota and Hori’s nevus differ in appearance, distribution and possible eye involvement [1][2][3].

At STC, we do not begin with “How many sessions will I need?” We first work out what the pigment is likely to be, whether it is superficial or dermal, one-sided or bilateral, when it first appeared, and whether the sclera is involved. Only then do we plan the Pico settings and treatment pace.

First, what does “deep freckles” mean?

In Thailand, the phrase commonly translated as “deep freckles” is used for grey-brown, blue-grey or deep-looking facial spots. Medically, it does not describe one specific condition. Some people use it for Hori’s nevus, while similar-looking pigment may instead be nevus of Ota, mixed melasma or post-inflammatory hyperpigmentation.

That is why the label alone is not enough to choose a wavelength, energy level or session count. Colour matters, but so do distribution, age of onset and location.

What is nevus of Ota, and what does it look like?

Nevus of Ota is a dermal melanocytosis, meaning pigment-producing cells are located within the dermis. This makes the pigment appear blue-grey, slate-grey or grey-brown rather than the clearer brown of a superficial freckle. It may appear as scattered speckles or a broader patch.

It most often affects one side of the face around the forehead, temple, eyelid, upper cheek or side of the nose, following the ophthalmic and maxillary areas of the trigeminal nerve. It may be noticed in childhood or become more obvious later [1].

An important difference is that nevus of Ota can also involve the sclera, conjunctiva or deeper structures of the eye. A pattern suggestive of nevus of Ota—particularly visible scleral pigment or eye symptoms—may require ophthalmic assessment. A skin laser does not treat pigment inside the eye [1].

What is Hori’s nevus, and how is it different?

Hori’s nevus is also called acquired bilateral nevus of Ota-like macules, or ABNOM. It is an acquired dermal pigmentation condition, so it usually develops later rather than being a birthmark in the usual sense.

It typically appears as small grey-brown, blue-grey or slate-grey spots on both sides of the face, especially over the cheekbones, temples, forehead or lower eyelids. Early lesions may be separate brown spots and can become greyer and more confluent over time [2].

Compared with nevus of Ota, Hori’s nevus usually begins in adulthood, is bilateral and does not normally involve the sclera or oral mucosa. It can resemble melasma, and both conditions may occur together, so one photograph is not always enough to distinguish them [2][3].

A simple way to remember the difference

Nevus of Ota

Usually a unilateral grey-blue patch or speckled area around the eye, temple or upper cheek. It may start early in life and can include scleral pigmentation.

Hori’s nevus

Usually bilateral grey-brown or blue-grey spots over the cheekbones and lower eyelids. It is acquired later and normally does not involve the sclera.

When someone says “deep freckles”

The diagnosis is still open. The marks may be Hori’s nevus, nevus of Ota, melasma, post-inflammatory pigment, or more than one condition at the same time. These patterns are useful clues, not a substitute for medical assessment.

Does Pico laser treat both conditions in the same way?

Not exactly. Pico lasers deliver very short pulses that fragment pigment, and published evidence supports their use in both nevus of Ota and Hori’s nevus. However, the plan still needs to reflect the diagnosis, colour, depth, surface area, baseline skin tone and response after each session [4][5].

The doctor must choose more than a machine name: wavelength, spot size, energy, treatment endpoint and interval all matter. A broad unilateral nevus of Ota should not automatically receive the same plan as small bilateral Hori’s macules.

Why does dermal pigment need a gradual plan?

Dermal pigment rarely clears in one session. After laser treatment, the body needs time to process fragmented pigment, so several sessions are often required. Using higher energy simply to finish sooner does not guarantee a better result and can increase inflammation, post-inflammatory hyperpigmentation and hypopigmentation.

At STC, we compare standardised photographs, review how the colour changes after each session and adjust the plan to the skin’s response rather than promising a fixed session count before assessment.

What does STC assess before planning Pico treatment?

We ask when the pigment first appeared, whether it has been present since childhood or became noticeable in adulthood, whether it is unilateral or bilateral, and whether previous lasers or medicines have been used. We also look for sun- or hormone-related change and ask about scleral pigment, visual change, eye pain or other ocular symptoms.

If the pattern suggests periocular nevus of Ota, we consider the eye as well as the skin and recommend ophthalmic assessment when appropriate. If the distribution looks like Hori’s nevus, we also check for overlapping melasma or superficial pigment because each component may need a different plan.

Frequently Asked Questions

Is Hori’s nevus simply another name for deep freckles?

The terms are often used interchangeably in Thailand, but “deep freckles” is broader and less precise. Hori’s nevus has a recognisable clinical pattern, so the diagnosis should be confirmed before setting laser parameters.

Can Pico laser permanently remove nevus of Ota or Hori’s nevus?

Some patients achieve marked lightening, but complete clearance within a guaranteed number of sessions should not be promised. Results vary with diagnosis, pigment depth, skin tone, response and aftercare.

Does everyone with nevus of Ota need an eye examination?

Not everyone has ocular pigment. However, a clear periocular pattern, visible scleral pigmentation or eye symptoms should prompt appropriate ophthalmic assessment.

Can Hori’s nevus and melasma occur together?

Yes. A patient may have deeper grey-brown Hori’s macules together with more diffuse brown melasma. Treating every area with one setting may miss the real problem and may aggravate melasma.

If your pigmentation looks grey or blue-grey, or appears similarly on both sides, you can send STC front and oblique photographs taken in natural light for an initial review. Please also tell us when it began and whether the sclera is pigmented. An in-person assessment is still needed before treatment.

References

[1] Vishnevskia-Dai V, et al. Naevus of Ota: clinical characteristics and ocular classification. Br J Ophthalmol. 2021 — https://pubmed.ncbi.nlm.nih.gov/32229516/

[2] Ee HL, et al. Characteristics of Hori naevus: a prospective analysis. Br J Dermatol. 2006 — https://pubmed.ncbi.nlm.nih.gov/16403093/

[3] Park JH, Lee MH. Acquired bilateral nevus of Ota-like macules associated with Ota’s nevus. J Korean Med Sci. 2004 — https://pubmed.ncbi.nlm.nih.gov/15308859/

[4] Hu S, et al. Efficacy and safety of the picosecond 755-nm alexandrite laser for nevus of Ota and ABNOM. Lasers Med Sci. 2020 — https://pubmed.ncbi.nlm.nih.gov/31965352/

[5] Ungaksornpairote C, et al. Picosecond vs Q-switched Nd:YAG for epidermal and dermal pigmented lesions in Asians. Dermatol Surg. 2020 — https://pubmed.ncbi.nlm.nih.gov/32604235/