Health #04 | Alopecia Areata: The autoimmune hair disorder !

Hello everyone !  Welcome back to the new episode of Imagicnation ! A blog where we will reveal the answers to some of the most interesting & curious questions related to science...

Hey guys...how many of you are having hair disorders?? I guess most of us. Focusing on that, here I present you an article on an autoimmune hair disorder called Alopecia Areata. But, before jumping straightly into the topic, I really want you to know about the basics. So, let's start with a brief introduction of one of our skin appendages, the HAIR !

*So what actually is hair??

- Hair is a filament like structure composed of proteins (alpha keratin), that grows from follicles in the skin, or dermis. It is one of the characteristic features of mammals.

*How does our hair actually look like ??

L.S of hair:

It is made up of 3 parts:

- Hair shaft: It is the part of hair which is visible above skin.

- Hair follicle: It is the part of hair embedded in skin.

- Hair bulb: It is the deepest part of follicle.

Credits

Fig. Structure of hair

C.S of hair:

It is made up of the following parts:

- Medulla: It is the central core, present in terminal hair.

- Cortex: It surrounds the medulla in terminal hair. 

- Cover: Follicle is ensheathed by inner root sheath and outer root sheath.

*What are the types of hair??

Our hair is of 3 main types:

- Lanugo hair: These are fine, soft hair of fetus which are shed in utero but are retained rarely

- Vellus hair: Present on most parts of our body

- Terminal hair: Present on axillae, pubis, beard and moustache

*Hair cycle and growth:

It occurs in 3 phases:

- ANAGEN: active hair growth that lasts between two to six years

- TELOGEN: resting phase that lasts about two to three months. At the end of the resting phase the hair is shed and a new hair replaces it

- CATAGEN: transitional hair growth that lasts two to three weeks.

*What is Alopecia ??

- Alopecia is a condition in which hair is lost from some or all areas of the body, usually the scalp.  

It is a non-communicable disorder of the hair and occurs more frequently in people who have affected family members, suggesting that heredity may play a factor.

*What are the causes of Alopecia ??

The causes are shown below:

*What actually is Alopecia Areata (AA) ??

- It is a non-cicatrical, non-inflammatory disorder where there are large areas of hair loss with exclamatory mark hair at the edge.

*What is the cause behind Alopecia Areata ??

- AA is thought to be an autoimmune disorder in which the body immune system attacks it’s own hair follicles and suppresses or stops hair growth.

There is evidence that T type lymphocytes cluster around these follicles causing inflammation and lead to subsequent hair loss. However, an unknown environmental trigger such as emotional stress or a pathogen is thought to combine with hereditary factors to cause this condition.

*Epidemiology:

Gender:

- Male : female = 1 : 1

Age: 

- It can occur at any age.

*What are the clinical features ??

The features are :

Morphology:

- Discoid patch with no scaling, papules, inflammation or atrophy

Presence of exclamatory sign (!) is pathogmonic.

Site:

Scalp, less commonly on beard, eyebrow and eye lashes.

Course:

Unpredictable, i.e, there can be spontaneous recovery with regrowth or progresses to alopecia totalis or to even alopecia universalis

Variants:

- Ophiasis: Band like pattern.

- Alopecia totalis: Hair loss of entire scalp.

- Alopecia universalis: Hair loss of entire body.

All these three have very poor prognosis.

Association:

- There is thinning and pitting of nail plate. Unlike psoriasis, these pits are fine.

*What are the investigations to be done??

- Generally, it is not required.

- But, if suspected we must rule out other autoimmune disorders.

*How is the diagnosis done ??

- It is done on the basis of clinical features:

i) Non cicatrical patch of hair loss, without inflammation.

ii) Presence of '! mark ' hair at the edge of patch.

iii) Site of occurence: usually scalp, sometimes beard, mustache, eyebrows and eye lashes. Rarely entire body.

iv) Nail changes are seen.

*What are the Differential diagnosis ??

- Alopecia Areata should must be differentiated from:

i) Tinea Capitis

ii) Cicatrical Alopecia

*What is the treatment of Alopecia Areata ??

-If few lesions are present:

Less than 6 months :

- Spontaneous recovery is seen. 

More than 6 months :

-Topical therapy with steroids like Clobetasol, Mometasone etc.

-Minoxidil

-Topical calcipotriol, a vitamin D derivative, has been used successfully in treatment of areata

-If extensive lesions are present:

Oral corticosteriods: 

- May be used, but withdrawal often leads to relapse

- It is given daily or weekly doses.

- Associated with serious side effects.

Psoralens and PUVA

- They are only used in extensive lesions.

- They can be combined with oral steroids and given as OMP (Oral Mini Pulse)

Diphencyprone

- They are contact sensitizers

- Shows promising outcomes

Cosmetic cover using wigs (esp. for alopecia totalis)

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Credits 

So guys, I believe that's all you need to know about the basics of Alopecia Areata..there are definitely a lot things too, but I will be discusing on them on my coming days.

Hope you enjoyed that...

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Thank You !