Alopecia areata is an autoimmune condition where the body’s immune system is attacking the hair follicles, causing the hair to fall out. The natural history of the condition is usually unpredictable with patches of hair loss occurring, followed by regrowth and then potentially further patches of hair loss occurring.
It is often referred to in the community as just ‘alopecia’ however this term should always be qualified with the word areata as there are other forms of alopecia such as scarring alopecia, androgenetic alopecia etc. The terms totalis and universalis are descriptive terms referring to loss of the entire scalp hair and loss of the hair on the entire body respectively. Therefore, one would refer to these conditions as alopecia areata totalis or alopecia areata universalis to signify that these are particular presentations of the one condition, rather than a distinct entity.
Fortunately, the autoimmune-induced inflammatory response does not cause destruction of the hair follicle and so as the follicles are still present regrowth is always possible. This differs from some of the other hair loss conditions.
What causes Alopecia Areata?
It is thought that there is a genetic basis to alopecia areata as this condition does occur more commonly in some families than others. The problem with the genetic theory is that a person has the same genes all their life and so this does not explain why people can get patches of hair loss due to alopecia areata at different times throughout their life. We therefore look for an environmental trigger which may precipitate patches of hair loss in genetically susceptible people. The only trigger that is seen with any frequency is stress. The flipside of this is that many people develop patches of alopecia areata who deny any major stressors in their life at the time of hair loss.
The actual process of hair loss with alopecia areata is due to the body’s own white blood cells attacking the hair follicles which is why this is one of the autoimmune conditions.
Who is at risk of Alopecia Areata?
Alopecia areata occurs equally in men and women. It can affect up to 2% of the population at any one time. We do see it more frequently in teenagers and young adults and then there is a second slight increase in incidence in women around the menopause. It is also more common in people who have atopy which encompasses eczema, asthma and hay fever. It is also seen more frequently in patients who have other autoimmune conditions such as thyroid problems or vitiligo.
What are the symptoms of Alopecia Areata?
Alopecia areata is usually a symptomless condition with people just becoming aware of patches of hair loss. When the patches are small it is often the hairdresser or barber who may notice these rather than the patient. The patches usually start off small and can increase in size expanding out from the centre. Hair loss can be more dramatic with hair falling out in clumps causing larger areas of hair loss. A small percentage of patients experience a tingling or itchy sensation associated with the patches of hair loss. Some patients can predict where their next patch of hair loss is going to occur due to the sensations on the scalp.
When patches of alopecia areata occur on the scalp there can sometimes be a slight salmon-pink discolouration of the skin within the patch signifying inflammation, however apart from this the skin appears normal with no scaling. This is an important observation as many people assume that patchy hair loss is due to a fungal infection, tinea capitis, often referred to as ringworm.
Alopecia areata can affect any hair on the body and so patients may present with loss of hair from the eyebrows or eyelashes, patchy hair loss in the beard or hair loss from the body.
Images of Alopecia Areata
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How does a Dermatologist diagnose Alopecia Areata?
A Dermatologist who specialises in hair and scalp conditions diagnoses alopecia areata through examining the scalp, reviewing your medical history and through performing some in-consultation tests such as the hair-pull test. The Dermatologist may organise a blood-test screen to exclude other factors and medical conditions associated with alopecia areata and in a small number of cases, may request a biopsy where a small core of skin containing hair follicles is surgically removed and sent to a specialist pathologist for assessment.
How does a Dermatologist treat Alopecia Areata?
Alopecia areata can resolve of its own accord with the patches of hair loss growing back. Treatment options include topical steroids applied directly to the scalp in the form of a steroid scalp lotion rather than a cream or ointment for hair bearing areas or steroid injections directly in to the patches of hair loss using triamcinolone.
When the hair loss is more widespread Diphenylcycloprenone (DCP) treatment may be effective. This is a form of topical immunotherapy using a liquid containing DCP. The Dermatologist sensitizes the scalp so as to make the patient allergic to the chemical DCP. Increasing strengths of DCP are then applied to the scalp until an allergic reaction is precipitated. Although the exact mechanism is not known, it is thought that the inflammation of the allergic contact dermatitis that is created sends a down-regulating message to the inflammation around the hair follicles. Once the inflammation around the hair follicles resolves the hairs are then able to regrow again. This is a very specialised form of treatment that is only offered in some centres.
Oral immunosuppressant treatment can also be an option for treating more extensive alopecia areata. If the hair loss is very dramatic then a high dose of prednisolone can be used weaning the dose over a period of 6 to 8 weeks. Sometimes a low dose of oral prednisolone is used in conjunction with other treatments over a longer period of time, however this is not a long-term solution due to the side effect profile of prednisolone with prolonged use. Other immunosuppressant drugs used for the treatment of alopecia areata by Dermatologists with a special interest in hair include cyclosporine and methotrexate Both these drugs also have side-effects and so need to be prescribed by clinicians experienced in their use.
Phototherapy has also been reported as a treatment for alopecia areata however the response rate is very low and the treatment is quite time-consuming and so it is now rarely used for this indication.
Some results are being seen with platelet-rich plasma injections although this is still largely experimental and there is not a large amount of clinical evidence supporting this.
The latest breakthrough with alopecia areata is the discovery of the response of alopecia areata to the Janus kinase (JAK) inhibitors. This was discovered serendipitously when patients with alopecia areata were treated for other conditions with JAK inhibitor drugs and showed regrowth of hair. The two JAK inhibitor drugs that have have been found to help with alopecia areata are tofacitinib and rituximab which are used for arthritis and blood disorders such as myelodysplasia and lymphoma. Both these drugs are very expensive and can cause side effects and experience has shown that on ceasing the medication the regrown hair often falls out. The latest area of research in this field is to develop a topical formulation of one of the JAK inhibitor drugs to avoid side effects and hopefully also reduce cost. Whilst topical minoxidil is not a treatment as such for alopecia areata it can be used in conjunction with other treatments to try to hasten the regrowth of hair once the inflammatory infiltrate has been turned off.
Effective strategies for disguising alopecia areata include the use of hair fibres, clip-in or weave-in hair pieces or the use of cosmetic pencils to draw in eyebrows.