Types of hair loss

WHAT EXACTLY IS HAIR LOSS?

Hair loss, also known as baldness or alopecia is defined as an abnormal loss of hair from the scalp or the body.  The most common types of hair loss include androgenic alopecia (or female pattern hair loss), alopecia areata and telogen effluvium.  Hair loss that occurs with inflammation and scarring of the scalp include fungal infections of the scalp, lupus erythematosus, sarcoidosis.

Diagnosis of hair loss is based on clinical features, blood tests, the area of the body or scalp that is affected and the severity of the condition.  In some cases, a dermatologist can take a biopsy to assess scalp bacteria population or autoimmune activity around the follicle.

Treatment of hair loss conditions depends on the type of hair loss and the severity of the condition.

TYPES OF HAIR LOSS

Alopecia areata | Characterised by round or oval patches of hair loss on the scalp area. This is an autoimmune condition with a complex genetic influence. There are several associated diseases and conditions such as allergies and asthma.  The hair follicle suffers no permanent injury and hair will often spontaneously regrow after a period.

Zinc supplementation has been shown to be effective in women with alopecia areata.

Alopecia totalis | This is a more severe type of alopecia areata that affects the whole scalp area.  Most women with alopecia totals will experience at least partial hair regrowth. Treatment options are limited in the case of alopecia totalis.  The most successful treatments will focus on improving adaptive immunity function.  Immunotherapy is a good treatment option for alopecia totalis.

Drug-induced hair loss | Some types of medication can cause hair loss.  This type of hair loss is usually temporary but can be permanent in some cases.  The types of medication that can cause hair loss include those for diabetes, anabolic steroids, blood pressure problems and medication that treats heart disease.  Medication that alters hormone concentration or ratio such as hormone replacement therapy, the contraceptive pill and acne medications can also cause hair loss.  Some drugs used to relieve mycotic infections can cause severe hair loss.

Cicatricial alopecia (scarring alopecia) | This type of alopecia is particularly challenging.  Diagnosis of scarring alopecia requires interpretation of morphology of the hair follicle as well assessment of inflammation or fibrosing.

Scarring alopecia has been linked to low levels of vitamin D, low zinc and abnormal liver enzyme levels.  There are long term treatment plans or surgical interventions that have shown success in reversing the condition [2].

Hair loss due to seborrheic dermatitis | Associated with excess sebum production due to high levels of DHT.

Seborrheic dermatitis is a scalp condition where high levels of sebum build up on the scalp leading to what appears to be ‘adult cradle cap’.  This condition can lead to thinning hair.

Postpartum hair loss | Most women notice their hair thickens during pregnancy and starts to thin out some time after childbirth.  When a woman is pregnant, there will be an increase in anagen hairs.  In a study published in the Journal of Investigative Dermatology, it was found that in the third trimester, follicles in anagen phase increase from 90% to 94-100%.  They found that 6 weeks postpartum the percentage of follicles in anagen can be as low as 56% [1].  Pregnancy causes many changes in the body so there is not one clear explanation as to why hair loss occurs and no accurate way to predict the severity of hair loss after childbirth.  Postpartum hair loss should always be investigated by a trichologist, dermatologist or doctor to ensure the problem is not be worsened by a separate condition such as a thyroid condition or an iron deficiency.

Chemotherapy induced hair loss | Chemotherapy attacks fast growing cells such as keratin cells in the hair follicle.  Chemotherapy also leads to hair cycle abnormalities driven by the degeneration of tissue.  If the tissue is fully destroyed, the hair follicle will recover quickly by the beginning of new hair growth cycles.  If the hair follicle is only partially damaged, it will take considerably longer for the body to clear the damaged tissue and start a new growth cycle.

Telogen effluvium | More than 90% of all hairs should be in growing phase (anagen) and around 10% will be resting or in preparation to shed (telogen).  When the percentage of hairs in telogen phase reaches around 30-40% there will be a greatly reduced number of hairs on the scalp, this is often a cosmetic concern for a hair loss patient.  Normally, telogen effluvium is self-correcting and occurs after a period of ill health, surgery, a shock or a radical change in diet.  Cholesterol levels and poor blood glucose regulation can also trigger telogen effluvium.

Genetic hair loss conditions | There are several genetic hair loss conditions that cause unusual hair growth and hair shaft disorders.  There are several treatment options, though some conditions can be a therapeutic challenge.

Tumour-induced hair loss | Any tumour on the scalp or outgrowth of skin can cause localised hair loss.  The types of tumours associated with this type of hair loss include sebaceous nevus, basal cell carcinoma and squamous cell carcinoma.

Hair loss due to infection | Infections can cause hair loss directly or indirectly.  Some infectious conditions can trigger telogen effluvium 12 weeks after the infection has commenced.  Fungal infections of the scalp such as folliculitis decalvans, dissecting cellulitis and tinea capitis will need to be treated by a medical professional.

Frontal fibrosing alopecia | This is a type of scarring alopecia where the hair loss and fibrosing is at the hair line only.  Treatment for frontal fibrosing alopecia is the same scarring alopecia.

Frictional alopecia | Caused by rubbing of the hair follicles.  This type of hair loss is normally noticed on the ankles of men caused by the rubbing of socks.  Frictional alopecia is also associated with hair loss caused by regular wearing of hats and headscarves.

Traction alopecia | This type of hair loss is caused by mechanical force.  Hair loss occurs when the hair follicle is continually pulled by tight hair styles and the wearing of hair extensions.  Hair loss is unlikely to be permanent in these cases.  Often this type of hair loss occurs where hair thinning was already beginning.

Age-related hair loss | This type of hair loss is known as involutional alopecia.  This is where gradual thinning of the hair occurs due to a higher percentage of hairs switching from anagen phase into telogen phase.  This type of hair loss should be treated as telogen effluvium rather than being accepted as inevitable due to age-related decline.  Age related hair loss tends to affect women over 50.

THE FINAL WORD

There are many different treatment options for hair loss.  Firstly, it is important to diagnose the type of hair loss you have.  You may want to see your doctor, a trichologist or a dermatologist.

Hair loss is rarely permanent, but it is imperative that any type of hair loss be dealt with quickly as most types of hair loss increase in severity over time.

REFERENCES

  1. Effect of pregnancy on the human hair cycle. Journal of Investigative Dermatology, 35(6), pp.323-327.
  2. Cicatricial alopecia: clinico-pathological findings and treatment. Clinics in dermatology, 19(2), pp.211-225.