Alopecia Areata

 

History:  Single, Non-cicatrized patch of hair loss, noticed suddenly on the scalp

In Brief

• Non-scarring patterned alopecia, most commonly presenting as circular areas of alopecia

• Hair specific T cell mediated autoimmune disease with genetic factors involved in disease susceptibility and severity

• Usually self-resolving, though in some cases can progress to total scalp hair loss

Pathogenesis

T cell mediated response towards hair follicular auto-antigens are primarily seen. Normal growing hair follicle keratinocytes usually lack expression of class I and class II major histocompatibility antigens, which is responsible for sparing of the follicle by immunological forces. In alopecia areata, human leukocyte antigens (HLA-A, -B, -C, -DR) become expressed by the hair follicle, allowing an interaction of cytotoxic T lymphocytes with hair matrix cells

Disease Associations:

- Atopy: >40% of cases

- Autoimmune thyroid disease (e.g. Hashimoto’s thyroiditis- Commonest), vitiligo, inflammatory bowel disease

- Autoimmune polyendocrinopathy syndrome type 1 
- Type 1 diabetes increased in relatives of patients with alopecia areata

Types
1) Based on the extent of hair loss, AA is clinically classified as follows: patchy AA, in which

  there is a partial loss of scalp hair ; alopecia totalis (AT), in which 100% of scalp hair is lost, or alopecia universalis (AU), in which there is a 100% loss of all scalp and body hair. Approximately 5% of cases will progress to AT/AU. 

  2) Based on the areas involved and the pattern of hair loss, it can be 

  a) Classical pattern - Single/Few oval or round well defined patches(the first photo on this page) 

  b)  Band-like hair loss in parieto-temporo-occipital area (called as ophiasis pattern) 

  c)  Reticular (net like pattern)

  d) Ophiasis inversus (sisapho) (this is opposite of ophiasis, i.e Hair loss in the vertex and normal hair on parieto-temporo-occipital area(this type mimics Androgenetic alopecia)

  e) Diffuse loss from full scalp

 Associated abnormalities 

 a) AA can be associated with nail changes in as many as 66% of patients

 b) Autoimmune diseases, particularly thyroiditis (in 8-28%), are the most significant associations. The  presence of such abnormalities is one of the poor prognostic factors. The presence of thyroid autoantibodieshas no clinical correlation with AA severity. 

Vitiligo may be another important association, with a 3% to 8% incidence in AA patient 

 c) Other reported abnormalities include psychiatric and asymptomatic ophthalmologic changes.

Look for these words in any question on diagnosis of alopecia areata

- sparring of white hair in the patch of alopecia (as supposed antigen is melanin in the hair)
- hairs tapering at skin surface and thickening as it rises up  (EXCLAMATION HAIR). This is opposite of normal hair (larger at skin surface and thins as it rises up)
- patchy hair loss

On magnification of the patch of hair loss by a dermatoscope, scalp hair findings in areata on scalp are 

- black dots
- broken/ cadaveric hairs
- yellow dots
- exclamation hair (Explanation at bottom of post)
- Coudability hair (Explanation at bottom of post)

Pic (Ref: Seetharam KA, et al. IJDVL)

Prognosis
- Extent of hair loss determines the prognosis. Most patients will have morethan one episode
- About 80% spontaneous regrowth in the classical type at 1 year
- In children, thedisease may have a tendency towards worsening with time, even if the initial  presentation was mild

- In AT/ AU, the chance of full recovery is about 10%


Treatment (Ref: Dermatology. Bolognia 3rd Edn)

1. Topical and intralesional corticosteroids-  Intralesional corticosteroids are the treatment of choice for adults. (Triamcinolone acetonide 5mg/ml to the scalp and 2.5mg/ml to the face every 4 to 6 weeks).Topical midpotent corticosteroids are the treatment of choice in children. 
2. Topical irritants (e.g. anthralin, tazarotene, azelaic acid). Anthralin 0.5%- 1%, is mostly used as short-contact therapy (apply for 20-30 minutes initially, then contact time is increased gradually)
3. Topical minoxidil-  mainly used as adjuvant treatment to conventional therapy.
4. Topical immunotherapy (e.g. squaric acid dibutyl ester (SADBE), diphencyprone(DPCP)-  DPCP is the therapy of choice for adults with > 50% involvement. Sensitization with DPCP 2% is followed by weekly application of the lowest concentration that can cause mild irritation. This irritation is responsible for reflex hair growth
5. Topical or oral photochemotherapy (PUVA)
6. Excimer laser- may be useful in limited patchy AA
7. Systemic corticosteroids-The use of systemic corticosteroids is limited by their side effect profile and a higher rate of relapse
8. Systemic cyclosporine
9. Latanoprost, a prostaglandin F2 and bimatoprost, a synthetic prostamide F2 analogue have been used for AA of the eyelids.

Treatment for Alopecia Totalis and Universalis

- High Dose systemic steroids
- Topical immunotherapy (with diphencyprone or squaric acid dibutyl ester) 

MCQs

1) The classical nail change in Alopecia areata is
A) Oil drop sign
B) Yellow discoloration
C) Sandpaper nails
D) Pitting
Answer:  D
Expl: Pitting pattern is said to be regular (horizontal and vertical). Irregular, superficial  pits are seen in psoriasis (also called as thimble nails). Coarse pits are seen in eczema. Oil drop/salmon patch in psoriasis.  Sandpaper nails (also called as trachyonychia and 20 nail dystrophy) is seen in alopecia areata, psoriasis and lichen planus. Yellow discoloration is more indicative of onychomycosis

Oil drop / Salmon Patch sign- PSORIASIS

Yellow Discolouration- Onychomycosis

Horizontal nail pits in Alopecia areata

Other nail changes in Alopecia areata are

• Brittle nails

• Onycholysis

• Koilonychia

2) Poor prognostic factors in AA are all except

A) Nail Changes

C) Adult onset

D) Atopy

Answer: C
Ophiasis pattern is when Alopecia areata occurs on hair line margins like occipital, temporal, frontal margins. Early onset, atopy, thyroid disorder,  alopecia universalis, alopecia totalis, exclamation hair, positive hair pull test at margin of areata patch, Long duration of disease (> 5 years), Nail changes all have poor prognosis

3) Classification used in alopecia areata is 
A) CASPAR criteria
B) Hanifin Rajka criteria
C) Ikeda criteria
D) Ridley Jopling

Answer: C
Ikeda is for areata. CASPAR for psoriatic arthritis. Hanifin Rajka for atopic dermatitis. Ridley Jopling for leprosy.

Ikeda Classification:
1)Atopic type: It begins early in life and mostly (30-75%) progresses to alopecia totalis
2)Autoimmune type: It is seen in middle-aged groups associated with autoimmune diseases, diabetes mellitus and progresses to alopecia totalis in 10-50%.
3) Prehypertensive type: It is seen in young adults whose parents were hypertensive and progress fast to totalis in 40% of cases.
4) Common type: It affects adults aged 20-40 years and totalis develops in 5-15% of cases.


4) Commonest autoimmune association in areata is THYROID disease (hypothyroidism)

5) Histopathology of areata is

A) Clutching the ball appearance
B) Regular elongation of rete ridges
C) Saw tooth rete ridges
D) Swarm of bees appearance

Answer: D

A- is in Lichen nitidus
B- is in psoriasis
C- is in Lichen planus
D- in areata is accumulation of lymphocytes around hair follicle; like a swarm of bees.
he infiltrate is composed of both CD4andCD8 cells with the CD4/CD8 ratio being higher in clinically active disease

 

(Ref: Dermatology. Bolognia 3rd Edn)

6) Why do We get Exclamation hairs in Alopecia areata?

Normal hair is broad at bottom (bulb) and then it gradually tapers as it rises up. Exclamation mark hairs look exactly as they are named. They develop because of focal thinning causing weak points in the growth of the middle part of the  hair fiber causing the constriction. As the hair bulb is normal in areata, the bottom part is globular like the dot of an english exclamation mark. The upper part is also normal and middle part is constricted all like an exclamation mark. If you see this hair by naked eye, you would only see the part of hair above the skin (not the bulb). So it would appear that hair is thin at skin surface (the constriction part) and it thickens as it goes up. 

Extra edge points in areata- 
1) Coudability hairs (kink in the areata hairs, at a distance of 5-10 mm above the surface, where the hair is bent inwards)
2) Hair growth and maintenance depends on 3 phases of hair cycle, anagen (active growth phase), catagen (involution phase), and telogen (resting phase). In normal healthy individuals, hair sheds out after the resting phase when the new hair anagen growth starts. In alopecia areata, hair shedding occurs even before the anagen starts leaving the hair follicle empty (kenogen). Thus, AA is generally a disorder of hair cycling and is considered to be a state of kenogen.
3) Rarer associations in AA include Down syndrome, Addison disease, autosomal recessive autoimmune polyglandular syndrome (APS-1),  pernicious anemia, psoriasis, lupus, celiac disease,ulcerative colitis, and multiple sclerosis.  There may be an increased risk of type 1 diabetes in family members of AA patients, but not in patients themselves.

7) Most effective therapy for Alopecia areata is
A) Corticosteroids
B) Photochemotherapy
C) Minoxidil
D) Diphencyclopropenone (DPCP)

Contact sensitizers are the most effective treatment available.  But due to higher side effect profile, they are not first line. Dinitrochlorobenzene (DNCB), squaric acid dibutyl ester (SADBE) ,DPCP (most commonly tried) are the agents in this category. Works in alopecia totalis and universalis (traditionally very difficult to treat) in about 17% of pts. Can be given in children. Severe dermatitis, occipital lymphadenopathy are the side effects.