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Alopecia areata
This condition affects approximately 2% of people at some point in their lifetime. Hair loss can range from small circular patches to complete loss of scalp or body hair, though regrowth often occurs spontaneously.
Overview
Alopecia areata is characterised by sudden onset of non-scarring hair loss, most commonly appearing as round or oval bald patches on the scalp. The condition results from an autoimmune process where T-lymphocytes target the hair follicle, disrupting the normal hair growth cycle without permanently damaging the follicle structure itself. This means affected follicles retain the capacity to regrow hair, and many people experience spontaneous regrowth within months to years.
The condition can affect anyone regardless of age, though it most commonly begins in childhood or early adulthood. Whilst alopecia areata itself does not cause physical discomfort or systemic illness, the visible hair loss can significantly impact psychological wellbeing and quality of life. The unpredictable nature of the condition, with potential for regrowth followed by recurrence, adds to the challenge for affected individuals and their families.
Symptoms & clinical features
The hallmark presentation is one or more well-defined patches of complete hair loss, typically circular or oval in shape. These patches usually appear quite suddenly, often discovered by the affected person or during routine grooming. The scalp skin within the bald area generally appears smooth and healthy, without scaling, redness, or scarring. Some individuals notice short 'exclamation mark' hairs at the edges of expanding patches - these broken hairs are narrower at the base than at the tip.
The extent of hair loss varies considerably. Some people develop only a single patch that regrows within months, whilst others experience multiple patches or progression to more extensive patterns. Alopecia totalis refers to complete loss of scalp hair, and alopecia universalis describes loss of all body hair including eyebrows, eyelashes, and body hair. Nail changes occur in some individuals, presenting as pitting, ridging, or thinning of the nail plates.
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Affected organs
Alopecia areata primarily affects hair follicles across the body, with the scalp being the most common site. However, any hair-bearing area can be involved, including the beard area in men, eyebrows, eyelashes, and body hair. The follicles themselves are not permanently destroyed - they enter a resting phase and cease producing hair shafts whilst under immune attack, but maintain the structural capacity for regrowth.
Nail involvement represents the only other direct physical manifestation, reflecting shared developmental origins between hair follicles and nail matrix cells. The condition does not affect internal organs, though people with alopecia areata have slightly increased likelihood of other autoimmune conditions such as thyroid disorders, vitiligo, or type 1 diabetes.
Risks & severity
The clinical course is highly variable and unpredictable. Many people with limited patchy hair loss experience spontaneous regrowth within 6-12 months, though recurrence remains common. A substantial proportion of individuals see hair return naturally within one year even without intervention, though many will face recurrent episodes during their lifetime.
Several factors are associated with more persistent or extensive disease. Onset before puberty, extensive hair loss at first presentation, nail changes, atopic background, and family history of alopecia areata all correlate with less favourable outcomes. Complete loss of scalp or body hair carries a lower likelihood of full spontaneous regrowth. However, even in severe cases, regrowth can occur many years after onset, showing follicles retain their regenerative potential.
Genetic causes
Alopecia areata has a complex genetic architecture involving multiple genes that influence immune system function. Two genes included in genomic testing panels are CTLA4 and IL2RA, both of which encode proteins that regulate T-lymphocyte activity and immune tolerance.
CTLA4 produces a protein expressed on T-lymphocytes that functions as a brake on immune responses, preventing excessive activation. Genetic variants in CTLA4 can alter how effectively this regulatory mechanism operates, potentially increasing susceptibility to autoimmune reactions against the body's own tissues. IL2RA encodes part of the receptor for interleukin-2, a signalling molecule crucial for T-lymphocyte development and regulation. Variants in IL2RA may influence the balance between immune activation and suppression, contributing to loss of tolerance toward hair follicle antigens. These genetic factors increase susceptibility but do not determine whether someone will definitely develop the condition.
Inheritance pattern
Alopecia areata does not follow a simple inheritance pattern such as dominant or recessive. Instead, it is polygenic, meaning susceptibility results from the combined effects of variants in multiple genes, each contributing a small amount to overall risk. Environmental triggers likely also play a role, though specific triggers remain poorly understood.
Familial clustering occurs in some cases, indicating genetic factors contribute to risk. Having a close relative with alopecia areata increases an individual's likelihood of developing the condition compared to the general population. However, most people with alopecia areata do not have an affected family member, and most children of affected parents will not develop the condition. This complex inheritance pattern means genetic counselling focuses on empiric risk estimates rather than specific inheritance calculations.
Diagnosis & testing
Diagnosis is typically made through clinical examination of the characteristic hair loss pattern. A dermatologist will assess the distribution of patches, examine the scalp for signs of inflammation or scarring, and may perform a gentle hair pull test at the margins of bald areas. The presence of exclamation mark hairs strongly supports the diagnosis.
Scalp biopsy is occasionally performed when the diagnosis is uncertain or when other conditions need to be excluded, revealing characteristic lymphocytic infiltration around hair follicles. Genetic testing for variants in genes such as CTLA4 or IL2RA is not routinely used for diagnosis, as the condition is polygenic and many people without these variants develop alopecia areata. However, such testing may be offered through research studies or when there is suspicion of rare genetic syndromes with alopecia as a feature. Referral to dermatology within the NHS typically occurs through general practice, with most cases managed in outpatient settings.
Management & lifestyle
No curative treatment exists for alopecia areata, and management focuses on supporting hair regrowth and addressing psychological impact. Treatment decisions depend on the extent of hair loss, rate of progression, patient age, and individual preferences. For limited patchy disease, watchful waiting is often appropriate given the high rate of spontaneous regrowth.
When treatment is pursued, options include topical or injected corticosteroids to reduce local immune activity, topical immunotherapy to redirect the immune response, or systemic immunosuppression for severe cases. Response to treatment varies considerably between individuals, and regrown hair may be lost again if treatment is stopped. NHS dermatology services provide access to these interventions through specialist clinics. Psychological support, including counselling or connection with support groups such as Alopecia UK, helps individuals cope with the visible impact of hair loss. Cosmetic approaches including wigs, scalp micropigmentation, or hair systems can improve quality of life and are sometimes available through NHS services.
UK care pathway
Within the NHS, people with suspected alopecia areata are typically referred to dermatology services by their general practitioner. Initial assessment by a dermatologist confirms the diagnosis and establishes the extent and pattern of hair loss. For straightforward cases with limited patchy disease, management may involve monitoring or topical treatments initiated in primary care with dermatology advice.
More extensive or rapidly progressive cases warrant ongoing specialist dermatology follow-up. Whilst alopecia areata is not typically managed through the NHS Genomic Medicine Service, individuals with unusual presentations, very early onset, or features suggesting syndromic forms may be referred to clinical genetics services for further assessment. Multidisciplinary support including dermatology nurses, psychologists, and specialist wig services provides comprehensive care for those with significant hair loss.
Frequently asked questions
Will my hair definitely grow back?
Many people with limited patchy alopecia areata experience spontaneous regrowth within 6-12 months, but the condition is unpredictable. Regrowth is less certain with extensive hair loss or very early onset. Even when hair regrows, recurrence is common.
Can stress cause alopecia areata or make it worse?
The relationship between stress and alopecia areata remains unclear. Whilst some people report hair loss following stressful life events, research has not established a definitive causal link. Stress management may support overall wellbeing but should not be relied upon as primary treatment for the condition.
Is alopecia areata contagious?
No, alopecia areata is not contagious and cannot be transmitted between people. It results from an autoimmune process within an individual's own body rather than from infection or external exposure.
If I have alopecia areata, what is the chance my children will develop it?
Family history is present in some cases, indicating genetic factors contribute to risk. However, the inheritance is complex and most children of affected parents will not develop the condition. Genetic counselling can provide personalised risk estimates based on family history.
Are there any dietary changes that can help with alopecia areata?
No specific diet has been proven to treat or prevent alopecia areata. Maintaining overall good nutrition supports general health, but dietary modifications alone are not recognised as effective treatment for this autoimmune condition.
References
- King BA, Craiglow BG. Janus kinase inhibitors for alopecia areata. Journal of the American Academy of Dermatology. 2023. PMID: 37591562
- Sibbald C. Alopecia Areata: An Updated Review for 2023. Journal of cutaneous medicine and surgery. 2023. PMID: 37340563
- Gaurav A, Eang B, Mostaghimi A. Alopecia Areata. JAMA dermatology. 2024. PMID: 38265795
- Hordinsky M, Junqueira AL. Alopecia areata update. Seminars in cutaneous medicine and surgery. 2015. PMID: 26176283
- Alopecia areata. Nature reviews. Disease primers. 2025. PMID: 41198735
- Meah N, Wall D, Trindade de Carvalho L. Bitemporal alopecia areata. The Australasian journal of dermatology. 2020. PMID: 32141073
- Prie BE, Voiculescu VM, Ionescu-Bozdog OB. Oxidative stress and alopecia areata. Journal of medicine and life. 2015. PMID: 26361510
- Shetty S, Rao R, Kudva RR. Linear Alopecia Areata. International journal of trichology. 2016. PMID: 27625568