• Autoimmune attack on hair follicles (T-cell mediated)
• Patchy, non-scarring hair loss, smooth bald patches
• "Exclamation mark" hairs at margins (thin proximally, thick distally)
• Associated with other autoimmune diseases:
o Thyroid disease
o Vitiligo
o Pernicious anaemia
• Prognosis: variable; spontaneous regrowth common, but relapses frequent
• Treatment:
o Potent topical or intralesional steroids
o Immunotherapy (e.g., diphencyprone) in resistant cases
• Patterned hair loss, non-scarring
• Men: bitemporal recession, vertex thinning ("M-shaped")
• Women: central thinning, preservation of frontal hairline
• Dihydrotestosterone (DHT) mediated miniaturisation of hair follicles
• Treatment:
o Topical minoxidil
o Oral finasteride (men)
• Diffuse hair shedding, occurs 2–3 months after a trigger
• Common triggers:
o Severe illness
o Surgery
o Postpartum
o Psychological stress
o Rapid weight loss
• Usually self-limiting; hair regrows when trigger removed
• Fungal infection of the nail (dermatophytes most common)
• Features:
o Thickened, discoloured, crumbly nail
o Onycholysis (separation from nail bed)
• Diagnosis: nail clippings for fungal microscopy and culture
• Treatment:
o Oral terbinafine (first-line for dermatophytes)
o Itraconazole (alternative)
• Occur in up to 50% of psoriasis patients
• Key features:
o Pitting (small depressions)
o Onycholysis (distal separation)
o Oil drop/salmon patch discolouration
o Subungual hyperkeratosis
• Strongly associated with psoriatic arthritis
• Spoon-shaped nails, concave
• Associated with:
o Iron deficiency anaemia (classic)
o Plummer–Vinson syndrome (dysphagia + iron deficiency + oesophageal web)
• Transverse grooves or depressions, involving all nails
• Reflect temporary interruption of nail growth
• Causes:
o Severe systemic illness (e.g., sepsis, MI)
o Chemotherapy
o Trauma
Extra Revision Pearls
• Exclamation mark hairs → think alopecia areata
• Telogen effluvium → no true bald patches, hair pull test often positive
• Onycholysis in psoriasis vs fungal → psoriasis often with pitting and "oil drop," fungal with subungual debris
• Clubbing vs koilonychia → clubbing convex, koilonychia concave
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Author & Educational Disclaimer
Author:
Dr Phillip Cockrell BM FRCP DipClinEd
Dr Phillip Cockrell is a UK Consultant Physician in Internal Medicine, currently working at Queen Alexandra Hospital, Portsmouth University Hospitals NHS Trust. He has previously worked as a registrar across Intensive Care Medicine, Gastroenterology, Cardiology, Stroke Medicine, Acute Medicine, and Respiratory Medicine.
He has held senior leadership roles including Associate Clinical Director of the Acute Medical Unit, Clinical Director of Internal Medicine, and Chief of Medicine. Dr Cockrell has over 15 years’ experience in postgraduate medical education, having lectured extensively across the MRCP syllabus and contributed to MRCP revision teaching and course development.
Dr Cockrell holds a Bachelor of Medicine (BM), Fellowship of the Royal College of Physicians (FRCP), and a Diploma in Clinical Education (DipClinEd). His teaching approach is based on structured consolidation of complex medical topics to support efficient and effective revision for postgraduate examinations.
Purpose of this content:
The material on this page is intended solely for educational purposes to support revision for the MRCP (UK) Part 1 examination. It reflects examination-relevant principles of internal medicine and is designed to aid learning and pattern recognition.
Medical disclaimer:
This content is designed for postgraduate medical examination revision and does not constitute medical advice, diagnosis, or treatment guidance and must not be used as a substitute for professional clinical judgement, local guidelines, or specialist consultation. Clinical decisions should always be made in the context of individual patient circumstances and current national guidance.
