Alopecia Areata

 

Alopecia Areata (symptoms-bald patches) 

A condition affecting either gender in which one or more bald patches appear which may coalesce to involve significant areas of the scalp.

Symptoms usually include the characteristic stubble (exclamation hairs), crawling sensations.

The lesions may appear pink and spongy. The hair may eventually re-grow. Recurrence is always a possibility.

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This form of hair loss is a microscopically-inflammatory often spontaneously reversible loss of hair, usually presenting as sharply-defined patches of baldness (very occasionally diffuse).

It can involve scalp, beard, or other hair-bearing skin.

It is widely regarded as an organ-specific autoimmune response (an activity of the immune system), but some suggest psychosomatic implications.

There may be predisposition in families with a history of thyroid abnormality, eczema, asthma or hay-fever.

It can reportedly follow excessive, sudden or prolonged stress, surgery, physical injury, bereavement, financial crises and other human emotions inculcating the autonomic nervous system (sympathetic and parasympathetic) – which are generally beyond the control of the individual and may involve a breakdown within the sympathetic and parasympathetic nervous systems – adversely affecting hair-growth mechanisms. Body-chemistry abnormalities may also be implicated.

A.Areata can have a profound impact on the lives of both children and adults. Its onset can be sudden, unpredictable and recurrent. It progresses as hair-follicles prematurely enter catagen, telogen and exogen. The disease is not fully understood.
Existing white or non-pigmented hairs usually remain intact in the development of an A Areata lesion. This phenomenon is not understood although by definition white hair-shafts have inactive melanocytes at their germinal matrix at the time of onset of the condition.

The author observes that the disease, which may present as single or multiple bald patches of varying size which may coalesce may commence 6-12 weeks following the ’cause’. In some instances hair losses have been reported within days.

This paper seeks to discuss A Areata as an autoimmune disease, the epidemiology, diagnosis and treatments currently available.

A Areata is therefore the name given to hair loss in circumscribed bald patches, principally of the scalp and beard but potentially affecting any region of hairy skin. Alopecia of the beard should more correctly be termed A Barbae.
A Areata can progress to A Totalis (complete hair loss of the scalp).
A Areata can in rare cases progress into A Universalis (complete loss of all body hair). In this instance the prognosis is poor.
The aetiology of A Areata is not fully understood but it is believed to be an autoimmune response.
In many cases A Areata has a common denominator of stress or injury, but not all scientists support the theory.

Epidemiology

Statistical research data – provides the following estimations:
A. Areata affects 0.2% of the population, however this may be misleading as others may have suffered lesions which re-grew before discovery and are not therefore represented in these figures.
Gender incidence is equal.
Up to 40% of pre-puberty individuals suffering A Areata will develop A Totalis in adulthood with only a small number making a full recovery.
40-50% of all patients who develop A Areata will do so before the age of 21.
Approximately 10% of adult onset A Areata will develop into A Totalis with less than 10% making a full recovery.
Approximately 20% develop the disease after the age of 40.
Epidemiologists and Endocrinologists have observed similarities in patterns of hair losses in both identical (monozygotic) and non-identical (dizygotic) twins.
A link may exist between Down’s Syndrome and A. Areata.

Aetiology

A frequently held opinion is that A. Areata is an autoimmune response.  Other theories suggest psychosomatic influences.
A Areata as an autoimmune disease
The immune system
The immune system protects organisms from infection by the identification and destruction of pathogens (agents which infect their host) and which constantly evolve and avoid detection.
Immune cells responsible for fighting infection in the human body include:
Lymphocytes (syn:leukocytes or white blood cells) There are five types of these cells – the principle two being B cells and T cells. Each is specific for a particular antigen (it binds to a particular molecular structure).
B cells are produced and mature in the Bone marrow.
T cells leave the bone marrow and mature in the Thymus.
Dendritic cells (syn. Langerhans cells). These cells can produce branched projections (dendrites) from which their name derives. They are present in small numbers within the skin – at which point they are in close contact with the external environment. On activation, they migrate to the lymphoid tissue where they interact with T cells and B cells to initiate and manage the immune response.
Macrophages are cells within the tissues that originate from specific white blood cells (monocytes). Monocytes and macrophages are phagocytes, acting in both non-specific defence (or innate immunity) as well as specific defence (or cell-mediated immunity). Their role is to engulf and digest cellular debris and pathogens and stimulate lymphocytes and other immune cells to respond to the pathogen.
Immune cells are capable of recognising and responding to foreign micro-organisms invading the body as ‘non-self ‘antigens. However in an autoimmune disease the cells develop a response to certain ‘self cells’ as if they were foreign.

It is believed that in A. Areata hair follicle antigens come under attack from immune cells in this way.

Is A Areata an autoimmune disease? 

Differing opinions exist. The primary evidence that A. Areata is an autoimmune disease comes from the observation of immune cells around dystrophic hair follicles and, that some patients’ hair can re-grow following treatment with immuno-suppressive drugs. However some expert opinion disputes the theory that A Areata is an autoimmune disease due to the lack of tissue damage – in autoimmune diseases there is usually intensive irreversible tissue damage – this is not apparent in A Areata.

The disease is not fully understood – research is ongoing.

Alopecia Areata – Triggers

If we accept the philosophy that A Areata is an autoimmune disease – what triggers the onset?
Why is the incidence of the disease selective? – Genetic predisposition may be a factor. It is thought that susceptibility to develop the disease is polygenic and that a number of inherited genes are required to render an individual potentially vulnerable. These are not reported to be mutations or defective but are normal functioning genes.
Does psychological long-term stress and extreme shock trigger A Areata? Physical trauma has been linked with A Areata. Cells under physical stress can produce heat shock proteins (HSP’s). These have been implicated in other autoimmune diseases e.g. Lupus, forms of spondylitis, rheumatoid arthritis.
Drugs thought to initiate A Areata include: Zidovudine (HIV). Fluvoxamine (anti-depressant).

Diagnosis

Macroscopic diagnosis for A Areata can be unreliable. Confusion may exist. The initial A Areata lesions appear as smooth bald patches with or without ‘exclamation mark’ stubble (on or at the periphery). 

Other symptoms may include pruritus, tenderness or paresthesia (burning, tingling, numbness) in the affected area or in an area preceding the development of a new patch. The scalp most commonly affected, but the disease can affect any hairy region of the body. Pull tests conducted at the margins of lesions may be indicative of further activity.

Exclamation hairs

Scanning electron microscopy reveals abnormalities in hair-shafts which epilate with ease and fail to exceed 2 cm at the peripheral margin of an expanding A Areata lesion -These are referred to as ‘exclamation hairs’ – the distal portion of such hair growth is normal but the proximal section present with abnormalities e.g. it tapers, possesses no cuticle and has longitudinal cracks.
Hair analysis indicates irregular construction of the protein keratin resulting in weakness where hair-shafts readily break.

Nail growth may present with dystrophy varying from a diffuse fine pitting to severe alteration.

Differential diagnosis should exclude Tinea Capitis (infection of the scalp caused by microspora), Lichen Planus Chronicus (Planopilaris), Pseudo Pelade (Brocq), Folliculitis Decalvans and Lupus Erythematosus (an autoimmune disease), Trichotillomania (a compulsive disorder), Secondary Syphilis.

Where definitive diagnosis is required, biopsy may be employed. A 4mm diameter skin section is extracted under local anaesthesia for microscopic and /or serology examination. The positive presence of a dense infiltration of lymphocytes around the anagen hair bulb confirms a diagnosis of A Areata.

Treatments 

Nothing is certain, but levels of response have been achieved in some patients with the following.
Corticosteroids.
Dermatitis inducers .
Irritants
Minoxidil
8-methoxy-psoralen + UVA = PUVA
Other.

Corticosteroids mimic the steroidal hormones produced by the adrenal glands.
Administration method:
Topical lotions or a creams
Intralesional injections
Systemically via injection or oral medication.

Topical Corticosteroids.
Potency varies from 0.5% to 2.0%. Figures suggest a high response rate in prepubertal children but lower in adults (double-blinded study).
Potential side effects include; folliculitis, localised eczema, skin thinning.

Intralesional corticosteroid injection – sited as near as possible to the affected follicles. Injections may be administered using a ‘Pan-jet system’ – which although faster and less painful is unpopular with some. Positive results if achieved may be seen after 8 + weeks. Side effects: pain and possible atrophy at the injection site.

Systemic corticosteroids
Normally indicated for A Areata A Totalis or A Universalis. This is administered as intramuscular injection or oral medication. Potential side effects include: hypertension, weight gain, acne, menstrual problems, migraine, stunted growth in children, osteoporosis. This is last resort treatment.

8-methoxy-psoralen + UVA = PUVA –
A combination of UVA actinotherapy with 8-methoxypsoralen ( an irritant and immuno-modulator). PUVA is not popular due to the frequency required, danger, and low success rate.

Minoxidil (Regaine, Rogaine or Headway) a topical vasodilator with mixed but unconvincing success rates. Currently being prescribed in conjunction with other treatments.

Retin A – Tretinoin
Used in conjunction with minoxidil. The Retin-A gel is applied in the evening (out of sunlight) with minoxidil during the day.

Irritants and contact dermatitis inducers
These interrupt cell differentiation in the skin. The damage caused stimulates immune cell activity.

Non-specific irritants:
Irritants (iodine, chrysarobin, croton oil, capsicum etc) have historically been used to treat A Areata.
UVA is currently considered undesirable due to low success rates and potential side effects.

Anthralin (Dithranol, Dithrocreme)
– an irritant currently in used in varying concentrations. The response rate is unpredictable.

Contact dermatitis inducers (may be used in severe cases of A Areata)
Di-nitro-chloro-benzene (DNCB) – 63% success rate (Swanson 1981)
Di-phenyl-cyclo-propenone (DPCP) – 38% success rate (Shapiro 1993
Squaric-acid-dibutyl-ester (SADBE) – 70% success rate (Flowers 1982)

These results are disputed by some. Discrepancy may relate to the definition of ‘re growth’

Contact dermatitis inducers work by sensitising the immune system. A low level of the drug is initially applied and adjusted until a reaction is established. The treatment should be monitored.

Conclusion.

The Trichologist’s Role – Caution: Only highly trained trichologists should be consulted.

A Areata has significant physical and psychological implications (affecting self esteem, confidence and appearance). Diagnosis and treatment of a patient with bald patches can be about offering psychological support.
Bald patches can and often are misdiagnosed. The trichologist is usually consulted as a second opinion.

A Areata cases can represent a major part of the trichologists daily work.

Experienced trichologists have come to respect combinations of Actino + Electro therapies and Laser as safe sensitising procedures used in conjunction with short periods of local Hydrocortisone or Anthralin. Results are positive in many cases where others have failed.

 

© Prof. B Stevens FTTS – Contact the author

 

 

 

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