How covid-19 can affect the hair cycle

The function of hair goes far beyond our own image: it includes aspects such as touch, sensitivity and protection of holes and skin from ultraviolet (UV) radiation.  fashionbeautypalace

Hair is born in the hair follicle (or root), a kind of "factory" located in the deep layer of the skin that develops during the first half of pregnancy.  techgeeksblogger

It is estimated that each person has about 5 million of these roots spread over almost the entire surface of the body, of which almost 100,000 are found on the scalp. This number does not change in adulthood.  triotechdigital

The vast majority of follicles produce one strand at a time in a complex “manufacturing” process at the root.  computertechreviews

This process involves cell division, which produces the cells that underlie hair growth, and then elements such as sebum-producing glands to maintain and be flexible, melanin-producing cells to color the hair, and papillae that take care of life cycle of hair. ...  gethealthandbeauty

Pulling, for example, the thread "from the root" can damage this "factory".

In simple terms, what we call a strand of hair is the “top” of the structure that starts at the root. That is, we see a stem of dead cells that has been mostly covered with keratin, a protein that guarantees the support of this multilayer structure.

In general, this life cycle lasts from two to seven years and is divided into three phases.

First, hair grows by almost 1 cm per month for three years, on average, in the so-called anagen phase.

Then he spends two to three weeks in the catagen phase, when the hair stops “feeding” new cells at the base, stops growing and prepares for replacement.

The third and final phase is the telogen phase (or resting phase), which lasts three to four months. It is then that the hair falls out, being forced out by new hair that forms in the same hair follicle.

Telogen outflow

The problem is that this cycle can change, for example, due to emotional problems, anemia, autoimmune diseases, or infectious diseases.

In these situations, the so-called telogen outflow can occur, which anticipates the end of the hair's life: a much larger part of the hair goes from the growth phase to the loss phase.

Each person usually loses 30 to 150 hairs per day. But under conditions similar to telogen outflow, the volume can reach 300 per day.

This more severe fall occurs as a general decrease in the volume of hair on the scalp as a whole.

In cases of severe covid-19-related baldness, there is a time lag between infection and hair loss.

Telogen efflux usually occurs three months after the trigger and can last three to six months.

“The reasons for the link between severe hair loss and COVID-19 are unclear. Diseases associated with high body temperatures affect hair growth in hair follicles, which remain in the resting phase of the hair cycle for two or three months and then fall out. ", explains Messenger from the University of Sheffield.

“This is why people with this infection lose their hair about two to three months after the event that caused it. It can be quite dramatic, but the vast majority of cases recover in a few months, ”he adds.