A small white bulb at the end of fallen hair is not, in itself, a cause for concern. It only indicates that the follicle has gone through the various phases of the growth cycle before the strand is shed. Although this is a normal process (even in the absence of any type of hair loss disorder), the white bulb is usually not noticeable until, or unless the shedding becomes excessive, prompting one to examine their fallen locks. .
If a disorder is suspected, an examination of the bulb can provide professionals with clues as to the type and cause of the disorder. The shape, size and color will determine what stage of the growth cycle the hair was in before it fell out; and if there is any abnormality.
The first phase of the cycle, the period of active growth, is called anagen. During this time, the hair is firmly anchored, deep within the follicle. Removing anagen hair from a healthy scalp would require vigorous and firm waxing. The tip would reveal a small rounded or slightly elongated pigmented bulb that may be surrounded by a gelatinous sac-like enclosure.
Once each individual hair has reached its maximum growth potential, the follicle goes into what is known as “catagen”. Although the catagen lasts only one to two weeks, during this time many changes take place that prepare the formation of the white bulb. The lower follicle shrinks. The inner root sheath disappears. Pigmentation ceases. Cellular material (such as that of the outer root sheath) that is no longer needed to support growth begins to migrate to the base of the strand.
Once all the catagen changes have occurred, the follicle enters what is known as “telogen.” In early telogen, the remaining cells that are no longer needed migrate to the base of the hair. Because pigmentation has ceased, these cells will not be pigmented. These unpigmented cells clump together to form the “mysterious white bulb that acts as an anchor to hold the hair in the follicle while it” rests “for about three months before being released. The telogen phase is also known as the resting period.
Any hair that falls out with a white bulb attached indicates that it has gone through the telogen phase before falling out. Due to the shape, these strands are also known as club hairs. This characteristic will be present in the normal daily molt. Unless the shedding is excessive, there is no cause for concern.
The most common condition that causes excessive shedding with an attached white bulb is telogen effluvium. Because any follicle at any stage of the growth cycle can be affected, the fallen strands can be of various lengths.
With alopecia areata, hair often falls out during the telogen phase, but in some cases it may shed during the anagen phase or it may come off. Affected threads may have an “exclamation point appearance”. A small portion of the strand just at the level of the scalp becomes very thin and gives the appearance of an exclamation point. Because the hair is very thin at this point, it can break as well. Although the most common form of alopecia areata causes bald patches, there are other variations of this condition that cause other, more severe patterns of baldness.
The absence of a visible white bulb could indicate that hair fell out during the anagen stage, as in loose anagen syndrome or anagen effluvium. It could also indicate that it broke instead of falling.
The size, shape, color, and condition of the bulb can provide valuable diagnostic information for the examining hair loss practitioner.