Hair Disorders

Alopecia Areata

•    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

Androgenetic Alopecia

•    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)

Telogen Effluvium

•    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

Nail Disorders

Onychomycosis

•    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)

Psoriatic Nail Changes

•    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

Koilonychia

•    Spoon-shaped nails, concave

•    Associated with:

o    Iron deficiency anaemia (classic)

o    Plummer–Vinson syndrome (dysphagia + iron deficiency + oesophageal web)

Beau’s Lines

•    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