Nail Pathology Study

Nail Pathology

• This is a study of nail conditions and abnormalities.

Learning Objectives

• Understand nail terminology, presentation, causes and management of common nail pathologies.
• Key pathologies include: Onychauxis, Onychogryphosis, Involution, Subungual Exostosis, Beau's Lines, Koilonychia, Onychocryptosis, Onychomycosis, Subungual Haematoma, Clubbing.

Nail Anatomy

• Images and detailed drawings illustrating the structure and parts of the nail, including the dorsal plate, ventral nail plate, nail matrix, eponychium, proximal nail fold, distal nail fold, lunula, nail bed, hyponychium, and ventral nail matrix.

Causes of Nail Diseases

• The causes of nail diseases are categorized as acquired and congenital problems.
• Acquired: Trauma, infection, dermatological change, vascular issues, and tumours can contribute.
• Congenital: Conditions present from birth.

Trauma-Related Nail Pathology

• Acute Trauma: Single, sudden injuries, such as stubbing a toe or being stepped on.
• Chronic Trauma: Frequent injuries over a span of time, such as improper nail cutting, lack of maintenance, or ill-fitting footwear.
• Anatomical changes may also be factors.

Onychauxis

• Characterized by thickened toenails.
• Podiatry abbreviation: O/X.
• Possible causes: Fungal infection, vascular insufficiency, neglect/poor care, dermatological factors, microtrauma, and traumatic episodes.
• Signs: Discoloration (brown/yellow), possible partial detachment from the nail base or subungual breakdown, abnormal thickening (hypertrophy) localized primarily on distal portion of nail, as well as possible transverse ridges.
• Pathogenesis: Disorganized nail plate and proximal nail fold, shortened proximal nail fold, reduced strength to act against forces, increased angle between matrixes and increased vertical nail thickness.
• Diagnosis: Visual observation of signs and symptoms, patient history, and potential lab tests
• Treatment: Reduction with nail nippers/files first, then drill, and/or removal of debris/callus. Nail surgery might not be required.
• Prognosis: Recurrence but manageable.

Onychogryphosis

• Characterized by ridged, enlarged nail sulci, and discolouration of the nail.
• Gross deformity, mimicking a ram's horn.
• Possible causes: Trauma, peripheral vascular disease (PVD), fungal infections, eczema, psoriasis, poor nail care

Onycholysis

• Refers to detachment of the nail plate from the nail bed.
• Signs: Detachment of the nail, distal-to-proximal detachment, presence of half moon shape, and detachment from lateral edges.
• Moisture and debris accumulation below the nail plate.
• Discoloration may be yellow/brown if fungal infection present.
• Underlying conditions may contribute
• Possible causes: Trauma, fungal infection, psoriasis, allergic reactions, and systemic issues
• Treatment: Nail trimming to proximal attachment, removing detached nail, addressing fungal involvement, and moisture concerns if necessary. Allergic responses should be assessed and allergens removed.
• Prognosis: If trauma is addressed, the nail will likely regrow on its own; but can be recurring and involve a larger area.

Onychocryptosis

• Ingrown nail with embedded spicule.
• Podiatry abbreviation: O/C
• Signs: Inflammation, oedema, bleeding/discharge, unpleasant odour, erythema (redness), heat; May be painful
• Underlying conditions may contribute
• Causes: Poor nail cutting techniques (picking of nails and skin, dermatillomania), trauma, involution of a more flexible nail, hyperhidrosis, maceration, ill-fitting shoes

Subungual Haematoma

• Bleeding beneath the nail plate, often following trauma.
• Signs: Initial redness, then black/purple discoloration from blood coagulation and oxidation.
• Localized inflammation may be visible.
• Pain may be present due to pressure buildup.
• Possible causes: Sudden trauma, sport-related activities, systemic conditions (e.g., haemophilia).
• Diagnosis: Observation of signs and symptoms, thorough history gathering, specifics about how it happened

Involution

• Increased transverse curvature of the nail plate, possibly unilateral or bilateral.
• May pinch into the skin, potentially a precursor to onychocryptosis
• Treatment: Removing pressure, trimming/resection of offending portion, and possibly nail surgery (PNA/TNA with phenolisation).
• Advice: Appropriate footwear, hygiene, and regular nail care.

Onychomycosis

• Fungal infection of the nail plate.
• Podiatry abbreviation: O/M
• Can involve total dystrophic O/M, superficial white O/M, or distal medial and lateral O/M.
• Pathogenesis: Fungi produce keratinase, breaks down keratin and affects the healthy nail plate
• Causes: Dermatophytes (most common), yeasts, and molds.
• Diagnosis: Visual signs & symptoms, laboratory testing (microscopy and culture).
• Treatment: Topical, systemic (oral medications, e.g., terbinafine), possibly destructive treatments.

Subungual Exostosis

• Bone outgrowth beneath the nail plate, commonly on the hallux.
• Often very painful.
• Possible causes: Idiopathic, trauma, ill-fitting shoes.
• Could be associated with severe trauma to the hallux.
• Diagnosis: X-rays
• Treatments: Surgical removal (exostectomy)

Nail Clubbing

• Distal enlargement of the digit, bulbous appearance to the nail plate.
• No abnormality to the underlying phalanx.
• Hypertrophic changes to surrounding soft tissues.
• Possible causes: Certain cardiovascular disease, smoking, malnutrition, endocrine disorders, and aortic aneurysm.

Koilonychia

• Spoon-shaped contour to the nail plate.
• No changes to nail thickness
• Possible causes: Iron deficiency anemia, dermatological conditions (psoriasis), occupational exposure to chemicals, some infections (onychomycosis)

Beau's Lines

• Horizontal ridges or dents on one or more nails.
• Appear at the lunula and then progress, typically superficial.
• Possible causes: Systemic illness, trauma, severe mental stress, certain infections, toxins
• Occurs about 1 month after initiating trauma.

Onychorrhexis

• Brittle, vertical ridges form on the nail plate

Nail Pitting

• Small, round depressions or notches in the nails.
• Associated with some skin and autoimmune diseases (e.g., psoriasis, eczema.)

Chromonychia

• Abnormality in nail color and pigmentation.
• Examples include Leuconychia, Yellow Nail, Green Nail, Melanonychia.

Further Nail Pathologies

• Onychophosis, Durlacher's Corn, Subungual Heloma Durum, Paronychia, Onychoschizia/onychoschisis, Onychomadesis, Pachyonychia, Onychotillomania, Onychopapilloma,

Post-Lecture Consolidation

• Review lecture notes and research articles.
• Attempt the MCQ quiz.