Trichology and Hair Loss for the Cosmetology Exam

What Is Trichology

Trichology is the scientific study of hair and the scalp. It covers hair structure, the growth cycle, scalp health, and the conditions that cause hair to thin, break, or fall out. Cosmetologists work in this space every day, but the role on the floor is limited. A licensed cosmetologist observes, refers, and adapts services. A cosmetologist does not diagnose disease and does not prescribe medication.

State boards expect you to recognize the major hair loss patterns, understand the growth cycle, and know when to send a client to a dermatologist or certified trichologist. Getting this scope of practice right is what keeps your license safe and your clients healthy.

The Hair Growth Cycle

Every hair on the head moves through a repeating cycle. Each follicle runs on its own schedule, which is why hair sheds gradually instead of all at once. The phases are anagen, catagen, telogen, and exogen.

A healthy adult sheds 50 to 100 hairs per day. That number is normal background loss as telogen hairs release and new anagen hairs push in. If a client suddenly notices clumps in the brush, on the pillow, or in the shower drain, the cycle has shifted and a referral may be appropriate.

Types of Hair Loss

The term alopecia simply means hair loss. The cause and pattern is what changes the conversation with the client.

Androgenetic Alopecia (Pattern Baldness)

This is the most common cause of hair loss in both men and women. It is genetic and driven by sensitivity to dihydrotestosterone (DHT), a hormone that gradually miniaturizes affected follicles. Each new growth cycle produces a finer, shorter hair until the follicle stops producing visible hair at all.

• Male-pattern: a receding hairline at the temples and thinning at the vertex (crown).
• Female-pattern: diffuse thinning across the top and crown with a preserved frontal hairline.

Pattern baldness is medical territory. Treatments such as minoxidil and finasteride are physician decisions. The cosmetologist supports the client with flattering cuts, volumizing techniques, and gentle styling.

Alopecia Areata

An autoimmune condition where the body attacks its own follicles. It shows up as sudden, smooth, round patches of total hair loss with no scaling or scarring. The skin underneath looks normal. In rare cases it progresses to alopecia totalis (all scalp hair lost) or alopecia universalis (all body hair lost). Refer to a dermatologist.

Telogen Effluvium

A diffuse shedding that begins 2 to 4 months after a major stressor. The trigger pushes a large group of anagen hairs into telogen at the same time, and they all shed together a few months later. Common triggers include serious illness, surgery, childbirth, severe diet or weight loss, and certain medications. Telogen effluvium usually reverses on its own once the trigger resolves.

Anagen Effluvium

Rapid loss of actively growing hair, most often from chemotherapy. Hair fibers break or shed within days to weeks of treatment. Regrowth typically starts after treatment ends.

Traction Alopecia

Caused by prolonged tension on the hair shaft from tight braids, weaves, extensions, ponytails, or buns. Loss usually shows along the hairline, edges, and parts where tension is highest. Reversible if caught early. If left long enough to scar the follicle, the loss becomes permanent. Cosmetologists are often the first to recognize this and should coach the client toward looser styles and rest periods between protective styles.

Trichotillomania

A behavioral condition where a person compulsively pulls out their own hair. Patches are irregular in shape with hairs of mixed lengths. This is not a styling issue and is not something a cosmetologist treats. Refer with care and discretion.

Postpartum Hair Loss

A specific form of telogen effluvium that follows childbirth. During pregnancy, more hairs stay in anagen. After delivery, those hairs shift into telogen together and shed about 2 to 4 months postpartum. It is alarming for the client but typically self-resolving.

Scarring (Cicatricial) Alopecia

Inflammation, infection, or burns destroy the follicle and replace it with scar tissue. The follicle cannot regenerate, so loss in the affected area is permanent. Examples include lichen planopilaris and central centrifugal cicatricial alopecia. Always refer.

Scalp Conditions That Affect Hair

Hair loss is often a downstream symptom of what is happening on the scalp. Recognize these on intake:

• Dandruff (pityriasis simplex): dry or oily white flakes, no inflammation, not contagious. Recommend a medicated cleansing shampoo.
• Seborrheic dermatitis: greasy yellowish scales with redness and itch. Often persistent. Refer if severe.
• Tinea capitis: a fungal infection of the scalp, usually with circular scaly patches and broken hairs. Contagious. Refuse service in the active phase and refer to a physician.
• Folliculitis: inflammation of the follicles, often with small pustules. Avoid chemical services on the affected area.
• Lichen planopilaris: a scarring inflammatory condition that destroys follicles. Refer.

Scope of Practice on the Salon Floor

Knowing where the line is keeps you, the client, and your license safe.

What a Cosmetologist Can Do

• Recognize abnormal patterns and document what you see during the consultation.
• Refer to a dermatologist or certified trichologist when something looks medical.
• Recommend gentle styling, low-tension protective styles, and rest periods between tight styles.
• Recommend gentle, sulfate-balanced products and avoid harsh detergents on a fragile scalp.
• Postpone or refuse chemical services on inflamed, broken, or actively infected scalp.
• Document client consultation notes about hair density changes, shedding, and breakage.

What a Cosmetologist Cannot Do

• Diagnose any condition. Even if the pattern looks obvious, the word is referral, not diagnosis.
• Prescribe or recommend medications such as minoxidil or finasteride. Those are physician territory.
• Promise regrowth, reversal, or any specific medical outcome from a salon service.
• Treat infectious conditions like tinea capitis with salon products.

What State Boards Test

The cosmetology exam typically pulls trichology questions from a short list of high-value topics:

• The names and order of the hair growth phases (anagen, catagen, telogen, exogen).
• The percentage of hairs in each phase, especially anagen at 80 to 90 percent.
• Normal daily shedding range of 50 to 100 hairs.
• Identifying alopecia areata versus pattern baldness versus traction alopecia by description.
• Telogen effluvium and its 2 to 4 month delayed shedding after a stressor.
• Scope of practice: when to refer, what not to diagnose, what not to prescribe.
• Recognizing infectious or scarring scalp conditions and refusing service when appropriate.

Walk into the exam knowing that anagen is growth, catagen is transition, telogen is rest, exogen is shedding, and the cosmetologist's job in any unclear hair loss case is to refer. That single sentence covers a surprising number of test questions.