What are the other Names for this Condition? (Also known as/Synonyms)

• Hypochromic Nevus
• Naevus Achromicus
• Non-Pigmented Nevus

What is Achromic Nevus? (Definition/Background Information)

• Achromic Nevus is a birthmark that is observed in males and females; it can be seen in up to 3% of the general population
• Usually 1 in 5 cases of Achromic Nevus is diagnosed at birth, or is noticed within the first few years of the child’s life. Though it is a congenital lesion, it does not run in families
• Skin lesions of Achromic Nevus are usually well-defined hypopigmented (color of skin is lighter than surrounding areas) macule or patch. The hypopigmented areas remain stable over time
• It is uncommon for these patches to disappear on their own. The most common sites include the back and chest area, but arms and legs have also been involved
• There are 3 variants of Achromic Nevus, namely:
  • Isolated Achromic Nevus
  • Segmental Achromic Nevus
  • Linear Achromic Nevus 
• Achromic Nevus is principally diagnosed thorough a physical examination
• A majority of individuals do not require any treatment, and this condition usually does not lead to any significant complications

Who gets Achromic Nevus? (Age and Sex Distribution)

• Achromic Nevus is seen in between 0.4% to 3% of the population
• Both males and females of all racial and ethnic groups can be affected
• It is seen all over the world; there is no particular geographical restriction

What are the Risk Factors for Achromic Nevus? (Predisposing Factors)

• The risk factors of Achromic Nevus are currently unknown

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider. 

What are the Causes of Achromic Nevus? (Etiology)

• It is speculated that Achromic Nevus is caused by a genetic defect
• In this genetic defect, the melanocytes may either be decreased in number or melanocytes do not make enough melanin pigment, resulting in lighter-skinned areas

What are the Signs and Symptoms of Achromic Nevus?

The signs and symptoms of Achromic Nevus may include:

• Well-defined, pale, lighter-skinned areas that are usually noticed at birth or in one’s early years of life
• There is no itching, bleeding, pain, or burning in these areas
• The lesions are usually single and measure a few millimeters to several centimeters in size
• The most common sites include the back and chest area. Achromic Nevus patches can also be seen on the arms and legs
• These lesions usually do not change over time. The size of the lesion may grow as the child becomes older, though new lesions do not develop
• Individuals with Achromic Nevus patches usually do not develop any new patches
• Very rarely, they may disappear without any treatment
• The sensation of pain, touch, or temperature is not altered in these hypopigmented areas. This helps in distinguishes it from other diseases such as leprosy

How is Achromic Nevus Diagnosed?

The following tests and procedures may be used to diagnose Achromic Nevus:

• Complete evaluation of the individual’s medical history and a thorough physical examination including of the skin
• During history taking, the physician may want to know the following:
  • When the symptoms began and whether they are becoming worse
  • List of prescription and over-the-counter medications currently being taken     
  • About one’s personal and family history of skin diseases, birth moles, etc.
• A dermatologist consultation is often necessary, as they are the experts in dealing with skin conditions
• Woods lamp examination will help in distinguishing Achromic Nevus from vitiligo, which is also of lighter pigment
• Skin biopsy may be rarely indicated, if the diagnosis is questionable, or if it resembles other skin conditions
• Tissue (skin) biopsy: A tissue biopsy is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be the gold-standard in arriving at a conclusion 

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis. 

What are the possible Complications of Achromic Nevus?

There are usually no complication observed in Achromic Nevus. However, in some cases the following may be noted:

• The pale skin patches may result in cosmetic issues, which can lead to psychological stress
• These patches may reappear after treatment using skin grafting techniques
• Cancers, such as squamous cell carcinoma and melanoma, may develop in the Achromic Nevus patches

How is Achromic Nevus Treated?

Treatment measures for Achromic Nevus depend upon the associated signs and symptoms and they may include the following:

• A majority of individuals do not require any treatment. However, a consultation with a dermatologist is important and often necessary
• If the skin patches are small, these may be excised completely
• If the skin condition causes cosmetic issues, then treatment measures, such as phototherapy, laser therapy, and skin grafting, may be used
• There are no definitive treatment methods to re-pigment the pale patches
• Sunscreen creams and lotions should be regularly applied on the spots, since the patches do not have melanin pigment to protect from the damaging effects of sun’s ultraviolet (UV) rays

The healthcare provider will be able to recommend the best treatment options based upon each individual’s specific circumstances.

How can Achromic Nevus be Prevented?

Current medical research has not established a method of preventing Achromic Nevus.

What is the Prognosis of Achromic Nevus? (Outcomes/Resolutions)

The prognosis of Achromic Nevus is excellent. There are usually no major complications associated with it.

Additional and Relevant Useful Information for Achromic Nevus:

• An important differential diagnosis is tuberous sclerosis, in which there are multiple, light-skinned patches (ash-leaf spots), unlike Achromic Nevus in which there is usually a single patch
• Nevus Depigmentosus, another name for the condition is actually a misnomer, since the patches are hypopigmented and not non-pigmented (i.e., depigmentosus)