Alopecia Areata

WHAT IS ALOPECIA AREATA?

The meaning of alopecia is hair loss. 

It is a recurrent nonscarring type of hair loss that can affect any hair-bearing area and can manifest in many different patterns.

In alopecia areata, one or more round bald patches appear suddenly, most often on the scalp. Alopecia areata is also called autoimmune alopecia, that can also cause diffuse alopecia. 

It develops when the body attacks its own hair follicles (where hair grows from), which can cause hair loss anywhere on the body

CAUSES 

It is an autoimmune condition, the immune system malfunctions and attacks the body's own tissues instead. In alopecia areata the immune system targets hair follicles, stopping hair growth However, the causes are complex and not well understood. A combination of factors likely underlies the disorder, including changes in many genes that function in the hair and skin and in the immune system. 

INCIDENCE 

It can affect people of all ages, although it most commonly appears in adolescence or early adulthood. It can affect males and females at any age. It starts in childhood in about 50%, and before the age of 40 years in 80%. Lifetime risk is 1–2% and is independent of ethnicity. A family history of alopecia areata and/or of other autoimmune disease are present in 10–25% of patients.

At least 8 susceptibility genes have been detected.

Patients with alopecia areata have higher than expected rates of thyroid disease, vitiligo, and atopic eczema.

There is an increased prevalence in patients with chromosomal disorders such as Down syndrome.

It is possibly drug-induced when arising in patients on biologic medicines. 

SYMPTOMS 

Most patients have no symptoms, and a bald patch or thinning hair is noted incidentally. Other patients describe a burning, prickly discomfort in the affected areas — this is known as trichodynia. 

The bald areas may have a smooth surface, completely devoid of hair or with scattered 'exclamation mark' hairs.

Exclamation mark hairs are 2 to 3 mm in length, broken or tapered, with a club-shaped root.

Regrowing hairs are often initially white or grey; they may be curly even when previously straight.

It may take months and sometimes years to regrow all the hair.

One patch can be falling out while another is regrowing.

Diffuse alopecia areata

• Sometimes called alopecia areata incognita

• Presents with sudden diffuse alopecia.

• Persisting hair tends to grey, thus descriptions of 'turning white overnight'

• Positive hair pull test

• Diffuse alopecia areata may be confused with telogen effluvium or hair loss due to medications.

Alopecia areata of the nails

• Nail disease affects 10–50% of those with alopecia areata.

• Regular pitting and ridging are the most common findings.

• May also cause koilonychia, trichodynia, Beau lines, Onychorrhexis, onychomadesis, onycholysis and red spots on the lunula.

IF PARENTS HAS ALOPECIA AREATA WILL THE CHILD HAVE IT?

A child has a greater risk of developing this disease, if a parent or close blood relative has (or had) alopecia areata. While the risk is greater, not every child with this increased risk will get alopecia areata. It depends person to person susceptibility.