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

• PMH (Progressive Macular Hypomelanosis)

What is Progressive Macular Hypomelanosis? (Definition/Background Information)

• Progressive Macular Hypomelanosis (PMH) is an asymptomatic condition that is characterized by numerous hypopigmented spots, usually on the abdomen and back. It is a common skin condition observed in young individuals of unknown cause
• Progressive Macular Hypomelanosis is often misdiagnosed for several other dyschromic conditions such as pityriasis alba and vitiligo. Dyschromia refers to conditions that are characterized by pigmentary changes on the skin, nails, and hair
• Individuals with Progressive Macular Hypomelanosis may be treated using topical applications, phototherapy, or oral medications. However, it is a benign skin condition that does not present any significant complications; although, it may persist for many decades

Who gets Progressive Macular Hypomelanosis? (Age and Sex Distribution)

• Progressive Macular Hypomelanosis is a common condition that is mostly observed in adolescents, teens, and young adults
• Both males and females are affected; a female preference is noted
• Worldwide, no racial and ethnic group predilection is noted, and all individuals are at risk. However, the condition is more often diagnosed in individuals with dark skin (in the tropics)

What are the Risk Factors for Progressive Macular Hypomelanosis? (Predisposing Factors)

• The risk factors of Progressive Macular Hypomelanosis 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 Progressive Macular Hypomelanosis? (Etiology)

Progressive Macular Hypomelanosis (PMH) is a skin condition of unknown cause. It is believed that certain genetic factors may play a role in its development.

• The role of certain bacterium, present in the hair follicles of individuals with PMH, is proposed by some researchers towards explaining the development of this condition
• It is thought that the Cutibacterium acnes (earlier Propionibacterium acnes) bacteria may cause a loss of color (pigmentation) in skin resulting in hypopigmented areas that characterize PMH
• However, not all individuals with PMH are known to present C. acnes bacterium. Also, not all individuals with acne develop PMH, since it is known that C. acnes plays a role in acne development

Other hypotheses placed forward towards explaining Progressive Macular Hypomelanosis include hormonal changes (in females) and post-inflammatory hypopigmentation that occurs secondary to other unidentified factors.

What are the Signs and Symptoms of Progressive Macular Hypomelanosis?

The signs and symptoms of Progressive Macular Hypomelanosis may include:

• Presence of numerous circular spots that are lighter than the surrounding skin (hypopigmented patches)
• These pale skin spots may be ill-defined (i.e., lacking well-defined boundaries)
• The lesions are smooth and non-scaly; there is no redness and inflammation observed
• Most of the lesions are concentrated around the lower back, stomach, and abdomen (lower trunk), but may rarely involve the thigh, chest, or neck region
• The condition is typically asymptomatic, meaning it does not present any itching, pain, or burning sensation

Even though termed “progressive”, PMH may remain stable for many years or exhibit slow progression over decades.

How is Progressive Macular Hypomelanosis Diagnosed?

The following tests and procedures may be used to diagnose Progressive Macular Hypomelanosis:

• Complete evaluation of the individual’s medical history and a thorough physical examination including of the skin
• Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• KOH tests to rule out a fungal infection
• Skin tissue biopsy: A tissue biopsy is performed and sent to a laboratory for a pathological examination. The 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

A diagnosis of Progressive Macular Hypomelanosis is difficult and challenging since it presents overlapping features with several other skin disorders. Hence, a differential diagnosis to eliminate other skin conditions may be needed before arriving at a definitive diagnosis. These include:

• Dermal leishmaniasis
• Mycosis fungoides
• Nummular eczema
• Pinta
• Pityriasis alba
• Post-inflammatory hypopigmentation
• Psoriasis
• Tinea (pityriasis) versicolor
• Tuberculoid leprosy
• Vitiligo

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 Progressive Macular Hypomelanosis?

• There are usually no significant complications from Progressive Macular Hypomelanosis
• However, in some cases, the pale skin patches may result in cosmetic issues, which can lead to psychological stress
• The condition may be present for several years to decades

How is Progressive Macular Hypomelanosis Treated?

There are no standard treatments available for Progressive Macular Hypomelanosis. The treatment may involve a combination of the following measures based on the evaluation of a qualified healthcare provider:

• Wait and watch approach
• Use of topical acne creams such as clindamycin and benzoyl peroxide
• Oral medications such as tetracycline and isotretinoin
• Phototherapy: UVA or narrowband UVB light irradiation therapy

How can Progressive Macular Hypomelanosis be Prevented?

Current medical research has not established a method of preventing Progressive Macular Hypomelanosis.

What is the Prognosis of Progressive Macular Hypomelanosis? (Outcomes/Resolutions)

• The prognosis of Progressive Macular Hypomelanosis (PMH) is generally good since it is a benign condition that does not present any complications
• The course of PMH may be variable and the condition may be longstanding, often taking 3-5 years to resolve. In some individuals, the condition may last for decades and improve in middle-age

Additional and Relevant Useful Information for Progressive Macular Hypomelanosis:

• There is no evidence to prove that the tumor formation is influenced by one’s dietary choices
• Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition

The presence of dirt on the body is not a causative factor for the condition. However, it helps to be clean and hygienic, which may help the condition from getting worse