By Julia,\nAfter writing many medical articles for the blog, I thought it would be a good idea to break down some of the common phrases in them. While some of you might be familiar with these terms, others might not know what the heck I’m even talking about. So to help cut down on confusion, I created this simple glossary of hair loss terms that you might see in my posts.\n5 ALPHA REDUCTASE\n5-alpha reductase is an enzyme that alters testosterone into dihydrotestosterone (DHT). This enzyme is responsible for androgenetic hair loss in humans, gradually reducing the growth phase of the hair (anagen phase). At puberty, 5-alpha-reductase leads to overproduction of sebum (sebaceous gland), which can lead to acne problems. The term reductase refers to the enzyme that decreases the energy sent into the chemical process of electron exchange (oxidation-reduction).\nALOPECIA\nAlopecia refers to an abnormal loss of hair. The diagnosis of normal or abnormal loss can reveal alopecia in many forms. The best known and most widespread form of alopecia is androgenetic alopecia. However, there are several other forms of alopecia that are caused by distinct factors.\nDifferent types of alopecia\nCongenital Alopecia\nCongenital alopecia is the rarest form of alopecia. Congenital alopecia is due to an absence of hair roots or an abnormality in the constitution of the hair itself. This often results in baldness since the hair follicles are permanently destroyed. The hair has no chance of regrowth. The only way to cover this baldness outside of wigs would be a hair transplant.\nAndrogenetic Alopecia\nAndrogenetic alopecia, also known as pattern baldness, is the most common form of hair loss. It results in a gradual and definitive decrease in the quality and quantity of the hair. It affects men and women. Male androgenetic alopecia usually evolves leaving the forehead and apex balding, while female pattern baldness is more spread out. In most cases, hair loss is often concentrated on the top of the head.\nDiffuse Alopecia\nThis is a form of baldness where hair loss, more or less regular, is generalized throughout the hair. Non-hereditary, this type of alopecia that can be acute or chronic. It’s usually an indicator of illness.\nAlopecia Circumscribed\nThe circumscribed alopecia, also called alopecia areata, is characterized by hair loss in a circumscribed (circular) area.\nANDROGENETIC ALOPECIA\nAndrogenetic alopecia is abnormal hair loss caused by both heredity and hormones. Indeed, androgenetic alopecia results from a genetic predisposition of the scalp making it more sensitive to male hormones (or androgens), specifically DHT (or dihydrotestosterone). Among men who have this type of hair follicle problem, 90% have androgenetic alopecia. In fact, in the androgenetic form, the lost hair is replaced by a thin down; people who suffer from it have the same number of hair as the others, but they are almost invisible to the naked eye.\nSCARRED ALOPECIA\nScarring alopecia is hair loss due to physical or chemical trauma to the scalp. In this type of alopecia, the root of the affected hair is permanently destroyed. Because of inflammation, there are scarred areas with fibrous tissue where the hair will not grow back. Various factors can be at the origin of this type of alopecia: accidents, burns, radiotherapy, bacteria or viruses, skin tumors, lupus, scleroderma, congenital anomaly, etc. In scarring alopecia, the skin of the affected scalp becomes smooth, shiny and usually of a different color than the skin that is not affected.\nCENTRAL SCARRING CICATRICIAL ALOPECIA\nCentrifugal Central Scarring Alopecia (CCCA) primarily affects women with frizzy hair such as African-Americans. This type of alopecia begins in the most covered part of the scalp, the top of the head, and then spreads to the sides of the scalp. The main cause of this type is the straightening of hair using chemicals or a straightener at a very high temperature. The most important symptoms of Centrifugal Central Scarring Alopecia are scarring severe scalp pain and abnormal hair loss.\nTELOGEN EFFLUVIUM\nTelogen effluvium (TE) is probably the second most common form of hair loss. TE occurs when there is a change in the number of hair follicles that can grow hair. When the number of hair-producing Gfollicles drops significantly for any reason during the resting, or telogen phase, a significant increase in dormant, telogen stage hair follicles occurs. Shedding is often the result of this. With TE, people never lose all their scalp hair completely, but thinning of the hair will be very noticeable with severe cases. While TE usually occurs on the scalp, it can affect other areas, like the eyebrows or pubic region. The good news for this type of hair loss is that regardless of the form, it’s reversible.\n\nYou can see all of Julia's posts here.