What’s the diagnosis in this case of patchy hair loss?

Clinical features

Presentation:

• Sudden‑onset, well‑demarcated, round or oval patches of non‑scarring hair loss on the scalp; often described as ‘coin‑sized’ (although sizes vary).
• May progress to include the whole scalp (alopecia totalis) or entire body hair loss (alopecia universalis).
• The underlying skin is normal or slightly red, but without scarring. Exclamation mark hairs (short broken hairs which taper proximally) may be seen in the area of hair loss.

Symptoms

• Usually hair loss is the primary feature – pruritus, burning or tingling may occur in some patients but are not typical.
• Psychosocial impact: hair loss, especially on the scalp, eyebrows, eyelashes or body hair, can cause significant distress, affect self‑image, social interaction and mental well‑being.

Affected areas

• Classically the scalp, but any hair‐bearing skin may be involved (eyebrows, eyelashes, beard, body hair, pubic hair).
• The pattern may be patchy (most common), but there are variants: ophiasis pattern (hair loss at the scalp margins), diffuse alopecia areata (sudden widespread thinning) and more extensive forms.

Epidemiology

• Lifetime risk of alopecia areata is approximately 1.7% in some populations.
• It affects children, adolescents and adults of all ages; many cases begin in childhood or early adulthood.
• No strong sex predilection is consistently observed, though the condition may be more noticeable and burdensome in those with darker skin tones.
• Associated with other autoimmune conditions (for example thyroid disease, atopy).

Diagnosis

Clinical evaluation

• History: onset (often rapid), number and size of patches, progression, family history of alopecia areata or other autoimmune disease, associated symptoms (e.g., nail changes, eyebrow/eyelash loss).
• Examination: inspect scalp and other hair‑bearing areas, look for discrete patches, exclamation‑mark hairs, nail changes, symmetry, signs of other hair‑loss types (e.g., androgenetic).
• Assess psychosocial impact and mental health (anxiety, depression) given the distress alopecia areata may cause.
• Note any triggers (e.g., recent illness, significant stress) though these are not always identifiable.

Investigations

• Typically no routine blood tests needed specifically for alopecia areata unless there is suspicion of other autoimmune disease (e.g., TSH, thyroid auto‑antibodies) or if the clinical picture is atypical.
• Dermatology department may use trichoscopy (dermoscopy of hair follicle features) or scalp biopsy in uncertain cases.

Differential diagnosis

• Telogen effluvium – diffuse hair shedding rather than discrete patches.
• Androgenetic alopecia – patterned hair loss, slower progression.
• Scarring alopecia (various types) – where hair follicles are destroyed and permanent hair loss results; in alopecia areata follicles remain viable (non‑scarring).
• Tinea capitis – especially in children, may present with patches of hair loss and scaling; requires fungal investigation.
• Trichotillomania – self‑inflicted hair pulling, broken hairs, irregular patches.

Red flags

• Rapidly progressive hair loss involving the scalp and body (i.e., progression to totalis or universalis) – early dermatology referral.
• Child onset with widespread hair loss – impacts psychosocial health, requires specialist input.
• Nail involvement with severe changes or widespread involvement – may indicate a more severe disease course.
• Presence of signs of scarring alopecia, scalp inflammation, itching/pain (not typical in alopecia areata) – suggests other diagnoses.
• Significant psychosocial distress (anxiety, depression, social withdrawal) – holistic care including mental‑health support needed.

Management

First line (primary care / early intervention)

Education and reassurance

• Explain that alopecia areata is an autoimmune, non‑scarring hair loss condition; follicles are not destroyed so regrowth is possible though not guaranteed.
• Discuss the natural history – many cases will have spontaneous regrowth especially if limited patches and short duration.

Sun protection and scalp care

• Although alopecia areata does not specifically increase sun damage, patches of bald scalp are vulnerable – advise on sunscreen/hat use.

Psychosocial and camouflage support

• Refer to patient support groups (e.g., Alopecia UK), consider wig referral or scalp micropigmentation if appropriate.

Topical therapy

• For limited patchy disease, potent topical corticosteroids (e.g., high‑potency once daily) may be initiated (not on face).
• Intralesional corticosteroids (e.g., triamcinolone acetonide) are commonly used in dermatology for small patches – this would require referral.

When to refer

• Extensive scalp involvement (>50 % of scalp), or involvement of eyebrows/eyelashes/body hair.
• Rapid progression, alopecia totalis/universalis.
• Children or adolescents with new onset.
• Failure of first‑line topical therapy.
• Significant impact on mental health or quality of life requiring psychological support.
• If systemic therapy is being considered (e.g., for severe refractory disease).

Patient education

Understanding the condition

• Alopecia areata is an autoimmune hair follicle disorder that causes hair to fall out in patches.
• The disease is non‑scarring, meaning follicles remain intact and hair regrowth is possible.
• Emphasise that while regrowth can occur (particularly in limited disease), there is no guaranteed cure and relapses are common.
• It is not infectious or life‑threatening, but the impact on emotional wellbeing can be profound.

Triggers and associations