It is not uncommon for hair texture to be altered as a result of injury to the scalp: examples include curly hair becoming straight or straight hair becoming curly. As the injury heals, normal hair texture often eventually returns as new hair is made.
The hair follicle can only respond in a limited number of ways to genetic programming, disease, or injury. Either follicles may be destroyed, the hair cycle altered, the quality of the hair changed, or a combination of these may occur. A typical alteration of the hair cycle occurs in common baldness (androgenetic alopecia), where the follicle progressively has shorter and shorter growth phases resulting ultimately in hairs so fine that they are hardly visible. In cases of malnutrition, pigment may be diminished, the calibre of hair may decrease and hair may be shed, not being replaced until nutritional status has improved. In certain genetic diseases, the structural integrity of the fibres may be so poor that hairs will break off at the surface of the skin, leaving little more than stubble behind.
Knowing whether a hair problem is due to a hair cycle abnormality or a structural problem with the hair fibres is very important in determining the nature of hair disorders.
Chemical/Mechanical Hair Damage
Brittleness and uneven construction of the hair shaft leading to breakage and an appearance of thinness to the hair can be caused by the same factors, or by harsh chemicals used to bleach, colour, straighten or curl the hair during styling; any of which can have a detrimental effect on the texture and integrity of the body of your hair.
Chemical and mechanical injuries to the hair or scalp can produce a number of different effects. The effects may be divided into two broad categories; abnormalities of existing hairs or abnormalities of hair production. Sometimes abnormalities may involve both of these categories.
Typical chemicals intentionally used to alter hair include bleaches, dyes, relaxers, and agents used for permanents. Almost any type of chemicals used to alter hair will cause some degree of damage but most cosmetic products if used in moderation will produce minimal unwanted side effects
Dandruff is the most common condition affecting the scalp. Skin is constantly renewing itself and dead cells from the scalp fall off as new cells form beneath them. Everyone loses skin cells in this way, but with dandruff the whole process is faster, so a greater number of cells are shed. The cells are also shed in clumps that are big enough to be seen by the eye as dandruff flakes, particularly when they land on dark clothing. The scalp can also be itchy. The medical name for this condition is pityriasis capitis.
Many people think that flaking occurs because their scalp is too dry, and stop using shampoo because they believe it makes the condition worse. This is not true. The flaking occurs due to the increased turnover of skin cells. Dandruff is believed to be associated with an overgrowth of a fungus commonly found on the skin and scalp, called Pityrosporum ovale.
As we age, the amount of hair pigment (melanin) that we produce lessens, turning the hair clear or 'grey'. Most people go grey from the front back, but again this is inherited. It is common too to get a streak of grey and a few people get a condition where the hair goes grey then natural colour alternately along its length every millimetre or so. This is nothing to worry about as your body is just deciding to produce then not produce melanin.
There is nothing to worry grey hair can look everything from sexy and sophisticated to ageing and draining depending on you.
TELOGEN EFFLUVIUM : Diffuse Hair Loss
It is normal to lose up to about 100 hairs a day on one's comb, brush, in the sink or on the pillow. This is the result of the normal hair growth cycle. Hairs will grow for a few years, then rest for a few months, shed, and regrow. Telogen is the name for the resting stage of the hair growth cycle. A telogen effluvium is when some stress causes hair roots to be pushed prematurely into the resting state. Telogen effluvium can be acute or chronic.
A considerable number of different causes for telogen effluvium exist. Among the common causes are high fevers, childbirth, severe infections, severe chronic illness, severe psychological stress, major surgery or illnesses, over or under active thyroid gland, crash diets with inadequate protein, and a variety of medications. Most hair loss from medications is this type and causes include retinoids, beta blockers, calcium channel blockers, antidepressants.