Another reason why hair falls out is lupus. Lupus is an autoimmune disease that may make your immunity system begin attacking your various healthy body tissues. According to Medical News Today, “this results in symptoms such as inflammation, swelling, and damage to joints, skin, kidneys, blood, the heart, and lungs”. It can also attack eyebrow follicle resulting sudden hair loss and including brows.
It is important to understand the phases of hair growth which play an important role when in further understanding some of the causes of hair loss. During the active phase known as anagen the cells multiply at the follicle and push out to form the shaft. It is followed by a transitional phase known as catagen where the outer layer of the hair shrinks and it becomes attached to the root. Thereafter there is a resting phase known as telogen where there is no growth or changes in the hair.
Dozens of other causes of eyebrow loss are also possible including a variety of infectious, autoimmune and inflammatory conditions. Consultation with a dermatologist or hair transplant surgeon is recommended. I strongly advise consulting a dermatologist before proceeding to hair transplantation for women over 40 with new onset eyebrow hair loss after age 40.
Giorgos Tsetis: Another reason Unilever was inspired to partner with us is that we really target three channels. Direct-to-consumer is one, then we target physician channels and salon channels; which are the hardest to convince. There's liability involved, so there's no doctor in the world who is going to recommend or endorse a product they don't believe in. We have about 350-400 physicians currently selling the product. A large amount of these doctors are thought-leaders or experts in the space, so they are known to speak about this issue on a world stage when it comes to new innovations. We also have each of the top 20 hair salons in the country carrying the product. There's a ton of celebrities who use the product as well. It is a premium product, but we've still made it affordable for people. When you look at other products on the market, our price point is comparable. We're also working on special programs for people in need who can't normally afford the product. If somebody is motivated, serious and really needs it -- we work to make sure they can get the product, and seek to serve as many people as possible.
Male pattern hair loss has been established as androgen-dependent because it is associated with changes in the androgen receptor and responds to antiandrogen therapy (Ellis et al., 2002). With FPHL, genes that encode aromatase, which converts testosterone to estradiol, are also implicated (Yazdabadi et al., 2008, Yip et al., 2009). The process of androgen biosynthesis is depicted in Figure 1.
Central centrifugal cicatricial (scarring) alopecia: This type of hair loss occurs most often in women of African descent. It begins in the center of the scalp. As it progresses, the hair loss radiates out from the center of the scalp. The affected scalp becomes smooth and shiny. The hair loss can be very slow or rapid. When hair loss occurs quickly, the person may have tingling, burning, pain, or itching on the scalp. Treatment may help the hair re-grow if scarring has not occurred.

Additionally, two other considerations are important for a patient who receives treatment for FPHL. First, there is a set of reasonable expectations in patients. Maintaining the current hair density can be considered a successful treatment because women tend to have further thinning as they age (Harfmann and Bechtel, 2015). Second, it is important to ensure that patients understand that progress is slow, and months or years can be required to see a significant improvement (Boersma et al., 2014, Yeon et al., 2011). In our practice, we wait at least 6 months to assess treatment efficacy.
Anagen effluvium occurs after any insult to the hair follicle that impairs its mitotic or metabolic activity. This hair loss is commonly associated with chemotherapy. Since chemotherapy targets your body’s rapidly dividing cancer cells, your body’s other rapidly dividing cells such as hair follicles in the growing (anagen) phase, are also greatly affected. Soon after chemotherapy begins approximately 90 percent or more of the hairs can fall out while still in the anagen phase.
While these factors contribute to hair loss for any woman, it’s particularly dicey for those of us with PCOS because when the follicle is exposed to our elevated androgens such as DHT (di-hydro testosterone, an active metabolite of testosterone) it gets damaged. Whenever a cell is damaged it generates oxidative stress which further alters the androgen receptor in the follicle perpetuating the issue. 
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