Dermatology Library

H

Hair Health:

There are several hair conditions listed below.

DANDRUFF

What is dandruff?

Your skin continuously sheds layers, with the scalp shedding more than any other part of the body. Dandruff is an excessive amount of larger-than-normal flakes of scalp that stick to the shafts of the hair where they may accumulate a build-up of oil, dust and hair products. These flakes eventually fall on the collars and shoulders of clothes in large flakes. There may be associated irritation or itching.

Symptoms of dandruff

  • White scales and flakes on the scalp which fall onto the shoulders are clear signs of dandruff.
  • Some irritation or itch may be present.

What are the causes of dandruff?

  • The most common cause is the abnormal overproduction and shedding of dead skin from the scalp.
  • Seborrhoeic dermatitis is a red, scaly and itchy rash that causes the scalp to shed skin cells excessively. The cause of this condition is unknown at present.
  • Pityrosporum is a microscopic fungus that is normally present on oily areas of the skin. People who have dandruff often have an unusually large amount of pityrosporum.

What you can do

  • Massage your scalp for a few minutes each day to stimulate the circulation and loosen dead skin cells. This can then be followed by vigorous brushing to remove loosened flakes.
  • Wash your hair regularly with an anti-dandruff shampoo with fungicides.
  • Rinse well to eliminate any build-up of hair products. Many people find that regular washing is beneficial, however some people may find their scalp gets irritated by frequent washing.
  • Oily hair can often benefit from rinsing with fresh lemon juice or cider vinegar diluted in water.
  • A dry scalp can often benefit from a warm oil treatment used once a week.
  • Massage olive oil, castor oil or linseed oil into your hair and scalp and warm in a hot towel for at least 10 minutes (preferably a few hours) before washing.
  • Avoid the excessive use of hair products (including dyes) and change shampoo if it is not proving effective. An allergy-free product may be of benefit.
  • Stress and negative emotions have been known to play a significant part in skin conditions such as dandruff, so relaxation techniques may be of assistance.

When to see your doctor

Dandruff is usually more cosmetic than medical and is generally considered harmless. However, in some cases, dandruff may cause thinning of the hair and may be stress-related. Severe persistent dandruff may be a symptom of more serious conditions such as eczema, psoriasis or seborrhoeic dermatitis, and you should consult your doctor.

BALDNESS

Baldness in men

The most common type of hair loss starts in males from about the age of 30. It is known as androgenic alopecia or ‘male pattern baldness’. It is thought to be hereditary, and dependent on the male hormone, testosterone. How quickly or slowly baldness develops, and the pattern of hair loss, appear to be genetically determined. Although this type of baldness can also affect women, the pattern of baldness is different in males and females.

Other forms of baldness

Hair loss that is not hereditary may be caused by pregnancy, hormonal or other medicines, severe nutritional deficiencies, chemotherapy, auto-immune disorders, an under-active thyroid or scalp trauma, including reactions to hair care products and hair grooming methods.

How does hair grow?

The human scalp contains about 100,000 follicles. These anchor the hair to the skin and contain the cells that produce new hairs.

Normal hair grows in 3 phases:

  1. The anagen or follicle growing phase starts growing the new hair. This phase is genetically determined and can vary from 2 to 5 years (the average is just under 3 years).
  2. The catagen phase is a transition stage between the growing and resting phases.
  3. The telogen or resting phase is a mature hair with a root, which is held very loosely in the follicle. The telogen phase generally lasts about 3 months. About 100 telogen hairs are lost from the human scalp each day.

In hereditary hair loss, the follicle becomes smaller, the anagen phase is shorter and the telogen hairs are shed faster.

When should you seek medical advice?

You should seek medical advice for hair loss if:

  • you are a woman who has recently given birth.
  • you have been diagnosed with an auto-immune disorder such as systemic lupus erythematosis (SLE), nutritional deficiency or thyroid disease.
  • you have been recently treated with chemotherapy or have used a hormonal medicine; or
  • the hair loss cannot be explained by hereditary factors.

HEAD LICE

What are head lice?

Head lice (Pediculus humanus capitis), also known as nits (which are actually the eggs of the lice), live, eat and breed on the hair and skin of the human scalp. They are small, wingless insects, about 2.5 to 3.5 mm in length. Head lice cannot jump or fly, but they can roam the scalp by moving from hair to hair with strong claws. Healthy head lice can be very difficult to see on the scalp as they move quickly when the hair is disturbed.

Female lice lay about 6 to 8 eggs every day. Eggs are laid close to their food supply - the scalp. The eggs (nits), which are small whitish flecks, are often seen behind the ears and towards the nape of the neck. They are attached firmly to the hair and are very hard to remove or slide along the hair shaft. This is in contrast to dandruff which is easy to slide along the hair shaft. Eggs hatch about 7 to 10 days after being laid.

How are head lice spread?

Because they cannot fly or jump, head lice must come in close contact with another person's hair or head to spread. This can be done by sitting or lying next to a person with head lice, or using the same hairbrush, comb or hat. Head lice infestations occur most frequently in schoolchildren because they tend to be in close personal contact with each other and to share brushes and combs. Head lice are not associated with a lack of cleanliness.

Symptoms of head lice

Head lice may cause the scalp to itch, although often there are no symptoms. An active infestation of head lice is diagnosed by looking at the scalp and hair and either finding a live insect on the scalp or finding an egg (a nit) within 1.5 cm of the scalp (older eggs are found more than 1.5 cm from the scalp).

Wet comb technique to find lice

To help detect head lice, you can use the wet comb technique. Simply apply any brand of regular hair conditioner to dry, untangled (brushed) hair. This stuns the lice. Then comb the conditioner through to the ends of the hair using a fine-toothed lice comb. Wipe the combings onto a tissue; inspect the tissue for lice and eggs as you go (live eggs will ‘pop’ when squeezed between the fingernails). If any lice or live eggs are present you need to treat the infestation as described below.

How are head lice treated?

If you find lice or live nits in the hair or in the combings after using the wet comb tecnique, you will need to treat the infestation. Generally, a special shampoo or lotion is used. Follow the directions on the package carefully using a clock to time how long the shampoo should be left on. Speak to your pharmacist for advice about what treatment to use.

As no treatment kills the eggs as well as the lice, treatment must be repeated in 7 days to kill the newly hatched lice from eggs that have survived the first treatment. You can check the effectiveness of the treatment by using the wet comb technique to check for lice and eggs one week after the second application of lice treatment.

Don't worry about washing all the bedding and clothes, eggs will not survive away from their food source after hatching. Check for head lice on the scalps of family members and close contacts. Only apply treatment if an active infestation is found - there's no need to treat everyone who has been in contact with the person who has had head lice.

HIRSUTISM IN WOMEN

What is hirsutism?

Hirsutism is the name given to the problem of having too much hair on the face or body, a problem which mainly concerns women. For each woman, it is a matter of personal preference how much hair she considers to be too much.

Hair grows from tiny hair follicles. Men and women have the same number and distribution of these, although there is a difference between races. For example, Caucasians have more hair follicles than Asians, and people from the Mediterranean have more than those from Northern Europe.

In women, the hair on most parts of their bodies is very thin, pale and almost invisible. This hair is known as lanugo. Under the stimulus of male hormones (known as androgens) lanugo hair becomes coarser and darker, making it far more obvious. This is sometimes known as terminal hair.

What causes hirsutism?

All women have small amounts of androgens in their circulation, made primarily in the ovaries and adrenal glands. When androgens are produced in excess, hirsutism is likely to occur.

The usual cause of excess androgen production is a condition called polycystic ovary syndrome. Usually, women with this problem have irregular or absent periods and may experience difficulty becoming pregnant. Rarer causes are tumours of the ovary or adrenal gland and Cushing's syndrome, in which the adrenal gland is overactive.

In many cases, no abnormality of the hormones is found and it may be that in those people the hair follicle is more sensitive to normal amounts of androgen. Other family members are often affected.

How is it treated?

Treatment of hirsutism is through a combination of cosmetic measures and treatment of the hormone imbalance. Once the lanugo has developed into terminal hair it cannot change back. Cosmetic methods such as electrolysis, waxing and depilation are therefore needed to remove the excess visible hair. At the same time, those with an excess male hormone can be treated in a variety of ways to prevent further unwanted hair appearing.

Halo Nevus:

A halo mole (or halo nevus) is a mole with a white ring, or halo, around it. Halo moles are not uncommon and are usually seen in children or young adults.

Head Lice:

Head lice infestation (also called pediculosis) is a major problem in the United States, throughout Europe and Asia. The problem is particularly common in schoolchildren.

Also see: Head Conditions

Hemangioma:

Benign tumors of the vascular endothelium. Hemangiomas of infancy are the most common type of hemangiomas, characterized by a unique natural history of growth in early infancy, followed by slow involution over the next several years. Hemangiomas may be present at the time of birth as so- called precursor lesions in approximately half of the cases. Rarely are they fully- formed tumors at birth. In the remainder of cases, lesions become evident after birth, usually within the second and fourth weeks of life.

Herpes simplex:

The herpes simplex virus (HSV) causes blisters and sores around the mouth, nose, genitals, and buttocks, but they may occur almost anywhere on the skin or mucous membranes. HSV infections can be very annoying because they may reappear periodically. The sores may be painful and unsightly. For chronically ill people and newborn babies, the viral infection can be serious, but rarely fatal. There are two types of HSV - Type 1 and Type 2.

Herpes zoster (shingles):

Herpes zoster, also known as shingles or zoster, is a viral infection caused by the same virus that causes chicken pox. Anyone who has had chicken pox can develop herpes zoster. The virus remains dormant (inactive), in certain nerve cells of the body, and when it reactivates it causes zoster. About 20 percent of those people who have had chicken pox will get zoster. Most people get zoster only once.

Hives:

See: Urticaria

Hydrocortisone:

A less potent corticosteroid incorporated into creams, lotions and ointments used to treat skin inflammation.

Hyperhidrosis (excessive sweating):

Hyperhidrosis is a chronic medical disorder that results in the production of excessive sweat. A recent study determined that the condition - once thought to be rare - actually affects approximately 2.8 percent of the U.S. population, or 7.8 million people. Even more compelling, one out of three people surveyed with the condition said their sweating was intolerable or barely tolerable. Many sufferers said they were depressed and frustrated with daily activities, and they experienced interference with work and romance and had difficulty meeting people.

Hyperpigmentation:

See: Ethnic Skin