1. ANDROGENETIC ALOPEcIA
NAZLI SEDA GÖKDERELİ

2. THE EFFECTS OF ANDROGENS ON HAIR GROWTH
Androgens are important in regulating hair growth.
Types of Hair. There are three types of hair.
Thick, pigmented hairs are called terminal hairs.
Terminal hairs on the top of the head and in the beard, axillary, and pubic areas are influenced by androgens.
*Lanugo hairs are the fine hairs found on the fetus; similar fine hairs (peach fuzz) found on the adult are called vellus hairs.
*Vellus hair is short, fine, and relatively nonpigmented and covers much of the body.
Hair on the rest of the body is independent of androgens

3. Each hair follicle perpetually goes through three stages in the hair growth cycle: *catagen (transitional phase), *telogen (resting phase), *anagen (growing phase) The causes of hair loss (alopecia) are numerous. Most hair problems seen by the practitioner are due to changes in hair-follicle cycling. Scarring alopecias are due to other causes.

4. HOW TO APPROACH HAIR LOSS?
History
Sudden vs. gradual loss
Presence of systemic disease or high fever
Recent psychologic or physical stress
Medication or chemical exposure
Examination
Localized vs. generalized
Scarring vs. nonscarring
Inflammatory vs. noninflammatory
Presence of follicular plugging
Skin disease in other areas
Diagnostic procedures
Hair pull test
Daily counts
Part width
Possible trichotillomania
Potassium hydroxide examination for fungi
Scalp biopsy
Hormone studies

5. DIFFERENTIAL DIAGNOSIS OF DIFFUSE NONSCARRING HAIR LOSS
Determine the time of onset and the duration of hair loss. Abrupt-onset telogen effluvium is most often related to a specific event.
Gradual or imperceptible onsets are more complicated and involve possible shortened anagen, as well as a differential diagnosis that includes alopecia areata, androgenetic alopecia, and diffuse primary scarring alopecias.

6. Androgenetic Alopecia in Men (Male Pattern Baldness)
Baldness in men is not a disease, but rather a physiologic reaction induced by androgens in genetically predisposed men.
The pattern of inheritance is probably polygenic.
Thinning of the hair begins between the ages of 12 and 40 years, and about half the population expresses this trait before the age of 50.

7. HamIlton Patterns
The progression and various patterns of hair loss are classified by the Hamilton male baldness classification system.
Triangular frontotemporal recession occurs normally in most young men (type I) and women after puberty.
The first signs of balding are increased frontotemporal recession accompanied by midfrontal recession (type II).
Hair loss in a round area on the vertex follows, and the density of hair decreases, sometimes rapidly, over the top of the scalp (types III through VII).

8. Pathophysiology
Androgenetic alopecia is due to the progressive shortening of successive anagen cycles.
There are two populations of scalp follicles:
1.Androgen-sensitive follicles on the top and
2.androgen-independent follicles on the sides and back of the scalp.

9. In genetically predisposed individuals, and under the influence of androgens, predisposed follicles are gradually miniaturized, and large, pigmented hairs (terminal hairs) are replaced by thin, depigmented hairs (vellus hairs).

10. Skin Androgen Metabolism
Testosterone is converted to the more potent dihydrotestosterone by 5areductase.
Skin cells contain 5a- reductase (types I and II).
The type I enzyme is found in sebaceous glands, and the type II enzyme is found in hair follicles and the prostate gland.

11. Testosterone and dihydrotestosterone act on androgen receptors in the dermal papilla.
They increase the size of hair follicles in androgen-dependent areas such as the beard area during adolescence, but later in life dihydrotestosterone binds to the follicle androgen receptor and activates transformation of large, terminal follicles to miniaturized follicles.
The duration of anagen shortens with successive hair cycles, and the follicles become smaller, producing shorter, finer hairs.
Androgenetic alopecia does not develop in men with a congenital absence of 5a-reductase type II.
Finasteride, which inhibits 5areductase type II, slows or reverses the progression of androgenetic alopecia.

12. Process
Inflammation surrounds the bulge area of the outer root sheath.
The inflammation may damage the follicle stem cells, which results in a decrease in hair-follicle density.
Hair follicles are still present, but removing androgens or treatment with minoxidil or finasteride does not result in the conversion of miniaturized follicles back to terminal ones.

13. TREaTMENT
The desire for treatment varies. Some men accept the inevitable; others find baldness intolerable.
Topical treatment (minoxidil), oral treatment (finasteride), and several surgical procedures are available.
The drugs can enlarge existing hairs and retard thinning in the vertex and the frontal regions.
They have no benefit for men who are bald or those with bitemporal recession without hair.
Benefits are seen in 6 to 12 months.
Treatment must be continued indefinitely. If treatment is stopped, benefits are lost within 6 to 12 months, and hair density will be the same as before treatment.
Patients who begin balding at an early age are most distressed and are tempted to consult nonphysician “experts” at hair clinics.
These clinics offer a variety of topical preparations, none of which has any value.
Selected patients may be referred for hair transplants, plastic surgical rotation flaps, or wigs.

14. MINOXIdIl Minoxidil was developed to treat hypertension!
It increases the duration of anagen, causes follicles at rest to grow, and enlarges miniaturized follicles.
These effects occur in only a minority of patients.
Minoxidil 2% (Rogaine) and 5% (Extra Strength Rogaine) are available over-the-counter in a solution or foam preparation.
Minoxidil increases nonvellus hairs.
Ideal candidates are men younger than 30 years of age who have been losing hair for less than 5 years.
The solutions produce a modest increase in hair on scalps of young men and women with mild to moderate hair loss, with continuous twice daily application for years to maintain the effect.

15. SIde effects of mınoxIdILE
One study found that topical use of 2% minoxidil caused small but statistically significant increases in left ventricular end-diastolic volume, cardiac output, and left ventricular mass.
Dizziness and tachycardia have been reported with 2% solution.
Local irritation, itching, dryness, and erythema may occur.
About one third of these patients grow hair that is long enough to be cut or combed.
Hair growth is evident in 8 to 12 months.

16. FInasterIde
Finasteride (Propecia 1 mg) taken daily is an effective oral therapy for androgenetic alopecia in men.
Based on global photographic assessment, finasteride (1 mg) is able to increase hair growth in all areas of the scalp affected by male pattern hair loss.
Androgenetic alopecia (male pattern hair loss) is caused by androgen-dependent miniaturization of scalp hair follicles, with scalp dihydrotestosterone (DHT) level implicated as a contributing cause.

17. Finasteride blocks 5areductase type II, which inhibits the conversion of testosterone to dihydrotestosterone and decreases serum and cutaneous dihydrotestosterone concentrations.
This slows further hair loss, inhibits androgen-dependent miniaturization of hair follicles, and improves hair growth and hair weight in men with androgenetic alopecia.
Finasteride is effective in men with vertex male pattern hair loss and hair loss in the anterior/mid area of the scalp.
Woman who are or may potentially be pregnant because of the risk that inhibition of conversion of fetal testosterone to DHT could impair virilization of a male fetus.

18. Side Effects of fInAsterIDE
In clinical trials 4.2% of men reported side effects related to sexual dysfunction, which resolved both after discontinuation and spontaneously in many men who chose to remain on drug treatment.
No other significant adverse effects related to finasteride treatment were observed.
Finasteride is beneficial in women with hirsutism, but the drug should be used cautiously in women because of its potential feminizing effects on male fetuses.

19. Hair Transplants
Hair transplants have been used successfully for years to permanently restore hair.
Age is not a determining factor.
Androgen-independent hairs from the lateral and posterior areas of the scalp are used.
The surgeon must have a sense of aesthetics to properly design the anterior hairline.

20. Scalp Reduction and Flaps
An anterior-posterior elliptic excision of bald vertex scalp with primary closure can provide an instant hair effect.
The procedure can be repeated every 4 weeks until hair margins converge or scalp tissue becomes too thin.
Grafts or flaps may be used later to fill any remaining void.
Alternately, several types of flaps can be designed by the creative surgeon to fill voids.

21. Adrenal Androgenic Female Pattern Alopecia
Chronic, progressive, diffuse hair loss in women in their twenties and thirties is a frequently encountered complaint.
These women, who usually have a normal menstrual cycle and lack any abnormalities on physical examination, have been classified as having “male pattern baldness,” a genetic trait, and have been dismissed without further evaluation.
Studies have shown that some of these women have increased levels of the serum adrenal androgen dehydroepiandrosterone sulfate (DHEA-S) and a distinct pattern of central scalp alopecia, which has been called adrenal androgenic female pattern alopecia.

22. COMPARISON OF MALE PATTERN AND FEMALE PATTERN ANDROGENETIC ALOPESIA
Male pattern baldness results in a gradual regression of the hair on the central scalp and gradual frontotemporal recession, as well as a gradual decrease in hair shaft diameter in the areas of hair loss.
In contrast, most women with diffuse alopecia experience a gradual loss of hair on the central scalp, with retention of the normal hairline without frontotemporal recession.
There are a variety of anagen hair diameters.
With advancing age, the central thinning becomes more pronounced; in contrast to male pattern baldness, a fringe of hair along the frontal hairline persists.
In exceptional cases, a course similar to that in men is seen, with deep frontotemporal recession.
Male pattern
Female pattern

23. Ludwig pattern
Evolution of the female type of androgenetic alopecia.
Stage I begins with thinning on the top of the head.
In stage II the scalp starts to show.
Finally, all of the hair at the crown of the head may be lost when the hair loss progresses to stage III.

24. Laboratory Findings
Laboratory evaluation for some androgenetic alopecia patients should initially in-clude determination of the
serum DHEA-S and total serum testosterone (T) levels,
testosteroneestradiol–binding globulin (TeBG) level for the T/TeBG ratio, and
serum prolactin levels.

25. Treatment
Once-daily 5% minoxidil topical foam is as effective for stimulating hair growth as twice-daily 2% minoxidil topical solution in women with androgenetic alopecia.
Finasteride is beneficial in women with hirsutism, but the drug should be used cautiously in women because of its potential feminizing effects on male fetuses.

27. Thank you for your attention…

28. sources
Clinical Dermatology Thomas P. Habif
Bologne