Trichology Study of hair

Root Located below the surface of the epidermis 5 main structures Follicle Bulb Dermal Papilla Arrector pili muscle Sebaceous (oil) Glands

Root fits over Dermal Papilla

Hair Root and Shaft

Hair follicle Tube like depression that encases the hair root Inserted into scalp at differing angles Inserted deep in the dermis Creates the hair stream ( parts) Distributed all over body Except palms and soles more than one hair will grow in a follicle

Bulb and Dermal Papilla Lowest part of the hair strand Thick, club-shaped structure- forms the lower part of the hair root Dermal Papilla Small, cone-shaped elevation Located at base of the hair follicle and fits into the hair bulb

Cool Fact The Arrector Pili muscle is small and works involuntarily at the base of the hair follicle. Strong emotions like fear or extreme cold cause it to contract, making the hair stand straight up…..otherwise known as “goose bumps”

Structure (cuticle) Cuticle- outer covering of hair Consist of single over lapping layer of transparent scale like cells Looks like shingles on a roof Barrier that protects inner structure: cortex Responsible for shine silky and smooth look Haircolor and chemicals relaxers must have an alkaline pH to penetrate the cuticle layer

Structure (cortex) Cortex-fibrous protein core formed by elongated cells containing melanin middle layer; respon. for hairs weight(90%) The elasticity of hair comes from cortex The changes involved in oxidative haircolor, wet setting, thermal styling, permanent waving and chemical hair relaxing take place in cortex

Structure (medulla) Medulla is the innermost layer of the hair Composed of round cells Fine and blond hair may lack a medulla All male beards contain a medulla Salon services do not involve the medulla

Keratinization Hair composed of protein: approx. 90 %:keratin Living cells within follicle begin to move up the hair follicle They mature; process called keratinization After cells fill with keratin they move upward They lose their nucleus, and die The emerge from follicle as nonliving fiber

Keratinization cont. The protein is made up of long chains: amino acids Which are made of elements called COHNS Carbon, oxygen, hydrogen, nitrogen, sulfur Proteins are made of long chains of amino acids

Amino Acid Units of structure that build protein Linked together in long chains, like pop beads Peptide (end) bond-chem bond links 2 amino acids Chemical bonds that join amino acid is a peptide bond: also known as end bonds Long chains of amino acids linked by peptide bonds make up the polypeptide chain

Polypeptide Chain

Chemical Composition of Hair COHNS Carbon 51% Oxygen 21% Hydrogen 6% Nitrogen 17% Sulfur %

Hydrogen weak physical side bond easily broken by water or heat; however, numerous and so account for 1/3 strength 6% can be found in normal hair Bonds can be reformed when the hair dries

Salt relatively weak; however, numerous and so account 1/3 strength Strong alkaline or acidic solutions will break bonds Reformed when the pH has been reformed

Disulfide -chemical bond; different from physical side bonds; fewer in number but stronger account for 1/3 not broken by heat or water chemicals like permanent waves and chemical hair relaxers change hair's strength change hairs disulfide bonds reformed by thio neutralizers disulfide bonds broken by chemical relaxers are broken permanently

Disulfide cont. Disulfide bond joins sulfur atoms of two neighboring cystein (sis ti een) amino acids to create one cystine Cystine joins two polypeptide strands

Hair Pigment pigment located in the cortex:melanin melanin is tiny grains of pigment gives natural color to hair two types melanin pheomelanin- red to ginger to yellow/blonde tones Eumelanin- brown and black color to hair

Wave pattern shape of hair strand any type of hair can occur in all races round cross sections usually straight oval cross sections wavy or curly extremely curly hair grow long twisted chains varies in shape and thickness along length as opposed to straight- uniform diameter

Terminal and Vellus Hair Long , course, pigmented hair found on the scalp, legs, arms, and bodies With the exception of gray hair, it is pigmented Usually has a medulla Vellus or lanugo hair Short, fine, unpigmented, and downy hair on the body Almost never has a medulla Commonly found on infants and sometimes on children until puberty

Growth Phases Anagen = The growing phase Catagen- Transition phase Average growth = 2 inches per month 90% of hair is growing at one time Grows for period of 2-6 yrs Duration is affected by age, gender, nutrition, health and your genes Grows faster on: Woman than men Between ages 15-30 and slowest after 50! Catagen- Transition phase Ends the growth phase Lasts only one to two weeks Follicle canal shrinks and detaches from the dermal papilla Hair bulb disappears and the shrunken root end forms rounded club Less than 1% in this phase at a time Telogen Follicle begins a 3-6 month resting phase About 10% of hair is in this phase at any one time

Phases of Hair Growth

Terminal and Miniaturized Hair

Hair Myths Shaving or cutting hair has no effect on growth Scalp massage will not increase hair growth. It may increase circulation. Minoxidil and finasteride are only treatments proven to grow hair. Women can not take finasteride: birth defects Gray hair is exactly the same texture as pigmented hair Race- all races have all hair types

Hair Loss Androgenetic alopecia Alopecia areata Loss due to miniturization of terminal hair that is turned into vellus hair Result of genetics, age, hormonal changes Can begin as early as teens but frequently seen by the age of 40 Alopecia areata Auto-immune disorder White blood cells stop the hair growth during the Anagen Phase Highly unpredictable skin disease Affects about 5 million people in the US alone! Starts with 1 or more small, round, smooth bald patches

Hair loss cont. Alopecia areata may lead to complete body hair loss (Alopecia Universalis)! Postpartum alopecia Temporary loss at the end of a pregnancy Little to no hair loss during the pregnancy leads to massive shedding from 3-9 months after baby Returns to normal within one year after delivery

Alopecia Areata

Hair Loss treatments Minoxidil Finasteride Topical medication applied to the scalp 2x’s a day Proven to stimulate hair growth Sold over the counter in 2 strengths 2% regular 5% extra strength No known side effects Finasteride Oral prescription for men only Side effects: Weight gain and loss of sexual function

Hair disorders Canities Greying of the hair: cause= loss of natural pigment in hair 1. Congenital- at or before birth 2. Acquired- due to old age, may occur prematurely in early adult life. CAUSE: worry, anxiety, nervous strain, prolonged illness Ringed hair- alternating bands of grey/dark hair Hypertrichosis- also known as hirsuties Superfluous hair; terminal grows in areas that vellus hair would typically grow Trichoptilosis- split ends Trichorrhexis nodosa- knotted hair Dry brittle condition that causes the hair to swell along the strand Breaks easily which causes a brush like spreading of the hair Monilethrix- beaded hair Breaks between the beads or nodes Fragilitis crinium- brittle hair

Canities

Disorders of the Scalp Pityriasis Two Types: Dandruff Small white scales that appear on scalp and hair Excessive shedding and accumulation of surface cells Caused by: Melassezia fungus Present on all skin but makes dandruff when it grows out of control Two Types: Pityriasis capitas simplex Pityriasis Steatoides

Pityriasis 2 Types Pityriasis capitis simplex Pityriasis steatoides Dry type; itchy scalp White scales that attach to the scalp and hair strands or scattered loosely in the hair Pityriasis steatoides Greasy or waxy type Scales become mixed with sebum; they stick to the scalp in patches Medical treatment is advised If redness and inflammation, medical term is “seborrheic dermatitis

Pityriasis Capitis classic type; large flakes itchy scalp

Pityriasis steatoides waxy, oily type

Pityriasis Steatoides

Shampoo for Scalp Disorders Contain: Pyrithione zinc, Seleiuem sulfide, or Ketoconazole **All to control dandruff by suppressing growth of malessezia

Fungal Infections Tinea Tineas favosa Technical term for ringworm Caused by vegetable parasites Highly contagious!! Begins with small, reddened patch of little blisters Refer to a physician Tineas favosa Honeycomb ringworm Dry, sulfur-yellow, cup-like crusts on the scalp called scutula Give off odor Scars from favus are pink or white, shiny bald patches VERY contagious!!

Tinea Favosa

Tinea Cont’d Tinea Capitis Ringworm of the scalp Characterized by red papules or spots at the opening of the hair follicles Causes hair to break

Tineas Capitis

Parasitic Infections Scabies Pediculosisi Capitis Highly contagious Caused by the itch mite Vesicles and pustules form from the irritation of scratching Pediculosisi Capitis Head lice Itching and scratching can cause infection

Pediculosis Capitis

Faruncles and Boils Faruncle or boil Carbuncle Staphylocci infection of hair follicle Produces constant pain A pustule perforated by a hair Refer to physician Carbuncle Inflammation of the subcutaneous tissue Caused by staphylococci Larger than a faruncle

Faruncle

Carbuncle

Texture medium- fine- coarse- most common standard to which all others are compared does not pose any problems Thinner than coarse and thicker than fine fine- smallest diameter and more fragile susceptible to damage: chemicals easier to process coarse- largest diameter requires more processing than medium or fine hair

Hair Density Hair texture diameter of individual hair Density refers to the number of hairs per square inch not very dense Very dense

Density Measures the number of individual hair strands per 1 square inch: Avg Head = 100K strands Low Density Thin Hair Medium Average or normal numbers per sq inch High Dense or thick

Density in Different Natural Colored Heads Average head- 2,200 hairs per sq inch Blondes- 140,000 Brown- 110,000 Black- 108,000 Red- 80,000

Porosity Hair Porosity= is the ability to absorb moisture directly related to condition of the cuticle layer healthy hair has compact cuticle which is naturally resistant to penetration Three types: Low Average High

Porosity cont. average porosity low porosity considered resistant Normal Hair slightly raised cuticle chemicals usually process as expected low porosity considered resistant hair w/low porosity harder to process: chemicals Requires more alkaline solution chemicals Considered resistant high porosity or overly porous often result of previous over processing damaged, dry, brittle requires less alkaline with lower pH So you don’t damage the hair further!

Elasticity ability to stretch and return to original shape indication of the strength of side bonds Hair with normal elasticity stretches: wet up to 50% dry stretches 20% low elasticity breaks easily may not hold curl from setting, styling or permanently waving chemical processing require mild solution/ low pH

Elasticity Test Test individual hair strands from 4 areas of the scalp Hold wet hair and pull to stretch returns to normal shape: good elasticity if breaks or fails to return to original shape: low elasticity

Hair Growth Patterns Hair Stream Whorl Cowlick Hair flowing in the same direction Result of the follicles sloping in the same direction Two streams flowing in opposite direction create a part! Whorl Hair that forms in a circular pattern, as in on the crown Cowlick A tuft of hair that stands straight up Can be anywhere on the scalp but more noticeable on the hairline

Compare and Contrast Hair Porosity to Hair Elasticity Hair Texture to Hair Density Dry hair and scalp to Oily hair and scalp