What is Pili Annulati?

Pili annulati (PA), also known as “ringed” or “Morse alphabet” hair, is a rare and harmless condition that gives the hair a unique spotted and striped look with alternating light and dark bands. This pattern is caused by an increased reflection of light due to the appearance of unusual air-filled spaces within the hair of the people affected by this condition. Pili annulati is part of a group of hair conditions that don’t cause the hair to become fragile. While there have been some random cases, it’s generally thought to be a disorder that you can inherit, or get passed down from your parents.

What Causes Pili Annulati?

Pili annulati, a condition that affects the hair of an individual, is mainly passed down through families. It follows what is known as an “autosomal dominant” pattern. This means if one parent has this condition, there’s a chance it could be passed on to their child. However, how this condition shows itself can vary from person to person.

According to research, the gene potentially responsible for causing this condition is located near the end of a specific part of our DNA known as chromosome 12q. However, scientists have yet to exactly pinpoint which gene causes pili annulati. So far, their investigations point to an area of 2.9 megabases (a unit of length for DNA) that contains 36 possible genes.

There has also been a unique case where pili annulati was linked with another condition known as Rothmund-Thomson syndrome. This occurred due to a mutation in the ‘RECQL4’ gene.

Lastly, there have been a few isolated instances of this condition that don’t seem to be related to certain families or genes.

Risk Factors and Frequency for Pili Annulati

Pili annulati is a hair shaft disorder that’s believed to be quite rare. It was first identified back in 1866, and since then, roughly 50 cases have been documented. It’s worth noting that this disorder seems to affect people of all races equally.

Signs and Symptoms of Pili Annulati

Pili annulati is a hair condition that can be noticeable from birth or during infancy. This condition can vary in appearance on different parts of the scalp or within different areas of the same hair strand. The hair of people with pili annulati usually has a shiny, banded look, and in some cases, it may have a glistening or frizzy texture. The bands do seem to fade as the hair grows longer. This condition doesn’t often lead to fragile hair. In fact, hair growth and strength are usually normal in people with Pili annulati. However, the abnormal areas on the hair strands might be more sensitive to weather changes and could present with slight surface irregularities. In rare cases, there can be severe hair fracturing and breakage.

Typically, Pili annulati affects the hair on the scalp, but sometimes it can also show up in other hair-bearing regions like the pubic, axillary (underarm), and beard areas. It is easily visible in blonde hair but can be difficult to spot in black hair because the pigment in dark hair can mask the banding appearance by absorbing light. As people with this condition age and their hair loses color, the banding appearance becomes more noticeable because of increased light transmission. In some reported cases, pili annulati was found in people with conditions like alopecia areata, autoimmune thyroid disorders, or primary immunoglobulin A deficiency. However, the link between these conditions is not yet clearly understood, and it is generally believed that their co-occurrence could be coincidental.

Testing for Pili Annulati

When we look at hair under a microscope, we see a special pattern of alternating bright and dark bands along the hair shaft. What’s interesting is that the dark bands seen under the microscope actually look like white bands to the naked eye, when light shines on them. When using trichoscopy, a simple and quick method to diagnose hair problems, similar bands can be seen.

Trichoscopy uses a special type of electron microscope for this purpose. The transmission electron microscope reveals that in affected hairs, the core (medulla) of the hair is normal but the outer layer (cortex) of the hair has pockets of air at irregular intervals. A scanning electron microscope shows that the hair cuticle (outermost part of the hair shaft) has a rough, “cobblestoned” look.

Trichoscopy can pick up on this regardless of hair color and shows bands that cover more than 50% of the hair shaft, giving the hair a foggy or “misty-like” appearance. However, these signs can be similar to ones seen in thick hair shafts in healthy people, which are called “intermittent medulla”. In these cases though, the lighter bands would cover less than 50% of the hair’s thickness.

Treatment Options for Pili Annulati

Pili annulati is a harmless condition that typically doesn’t require treatment. This condition makes the hair appear shiny, which most patients don’t find bothersome; in fact, some even find it appealing.

There have been a couple of instances where the onset of shiny hair – also referred to as the “ringed” look – disappeared with the daily application of a topical solution known as minoxidil.

In the uncommon cases where pili annulati leads to hair breakage or brittleness, it’s advised to handle the hair gently to prevent damage.

When trying to diagnose pili annulati, a condition that affects the appearance of hair, it’s important to consider a similar condition known as pseudopili annulati. This condition also causes the hair to have a banded pattern of light and dark. The bands in pseudopili annulati, however, are actually caused by the slight twisting of the hair shaft – not by variation in the hair’s color or structure. This can be confirmed using a hair magnification technique, trichoscopy, which can show that the hair is twisted and does not have white bands.

What to expect with Pili Annulati

The overall outlook for pili annulati, a hair condition, is generally good because it is a harmless condition that doesn’t impact a patient’s quality of life.

However, it’s important to note that as people with pili annulati get older, the condition tends to become more noticeable. This is due to the loss of pigment in the hair, which allows more light to pass through, making the hair appear brighter or more silver.