Cutaneous autoimmune disease (alopecia areata, vitiligo)

Question 1

Define alopecia areata.

Answer 1

Alopecia areata (AA) is an autoimmune disease that causes inflammation of the hair follicles resulting in non-scarring hair loss, affecting scalp and body hair.

At the edge of the hair loss, there may be small, broken ‘exclamation mark’ hairs

Question 2

How common is alopecia areata?

Answer 2

1 in 1000 prevalence
M=F
Up to 10% have the severe chronic form of the disease

Question 3

What is the aetiology of alopecia?

Answer 3

T lymphocyte directed at hair follicles

Question 4

What are the risk factors for alopecia areata?

Answer 4

Autoimmune disease - hyroid disease, vitiligo, type 1 diabetes, pernicious anaemia, and atopy
FH

Question 5

What are the clinical features of alopecia?

Answer 5

Hair loss - usually patchy, beard, brows, lashes included less commonly

Question 6

What is complete scalp loss and complete body hair loss called?

Answer 6

Complete scalp hair loss = AA totalis
Complete body hair loss = AA universalis

Question 7

What is the prognosis with alopecia areata?

Answer 7

Hair will regrow in 50% of patients by 1 year, and in 80-90% eventually. Careful explanation is therefore sufficient in many patients.

Question 8

What is the management of alopecia areata?

Answer 8

• careful explanation
• topical or intralesional corticosteroids
• topical minoxidil
• phototherapy
• dithranol
• contact immunotherapy
• wigs

Question 9

What investigations should be done for alopecia areata?

Answer 9

Clinical diagnosis but screen for other autoimmune diseases e.g. DM, thyroid,pernicious anaemia

• FBC
• TFTs
• HbA1c
• B12

Question 10

Define vitiligo.

Answer 10

Vitiligo is an acquired loss of melanocytes in circumscribed areas of the epidermis, resulting in complete depigmentation of affected skin.

Question 11

How common is vitiligo?

Answer 11

It is thought to affect around 1% of the population and symptoms typically develop by the age of 20-30 years.

Question 12

What are the risk factors for vitiligo?

Answer 12

Associated conditions:

• type 1 diabetes mellitus
• Addison’s disease
• autoimmune thyroid disorders
• pernicious anaemia
• alopecia areata

Age < 30yrs
FH
Chemical contact - monobenzyl ether of hydroquinone, rhododendrol, and other phenols

Question 13

What are the clincial features of vitiligo shown?

Answer 13

Round depigmented area - predilection to the acral (i.e. peripheries) and periorifical skin is shown.
Poliosis of several eyelashes also shown

Question 14

What sign of vitiligo is shown ?

Answer 14

Halo (Sutton) naevus - x10 more common in vitiligo

Question 15

How do you diagnose vitiligo?

Answer 15

Clinical diagnosis

Wood’s lamp examination -accentuates the contrast between affected and unaffected skin while fluorescence is a characteristic bluish tint typical of vitiligo.
Biopsy would show absent melanocytes

Question 16

What may precipitate new lesions in vitiligo?

Answer 16

Trauma (= Koebner phenomenon)

Question 17

What is the management of vitiligo?

Answer 17

1. Sunblock - for affected areas
2. Camouflage - make-up
3. Topical corticosteroids e.g. clobetasol topical 0.05% - may reverse the changes if applied early
4. +/- Topical tacrolimus and phototherapy - although caution needs to be exercised with light-skinned patients