Nail plate and soft tissue abnormalities

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Robert Baran, Rodney PR Dawber, Eckart Haneke, Antonella Tosti Onycholysis

Onychomadesis and shedding Hypertrophic nail and subungual hyperkeratosis Splinter haemorrhages and haematomas Dorsal and ventral pterygium Further reading


Onycholysis refers to the detachment of the nail from its bed at its distal and/or lateral attachments (Figure 4.1).

The pattern of separation of the plate from the nail bed takes many forms. Sometimes it resembles closely the damage from a splinter under the nail, the detachment extending proximally along a convex line, giving the appearance of a half-moon. When the process reaches the matrix, onycholysis becomes complete. Involvement of the lateral edge of the nail plate alone is less common. In certain cases the free edge rises up like a hood, or coils upon itself like a roll of paper. Onycholysis creates a subungual space which gathers dirt and keratinous debris; the greyish-white colour is due to the presence of air under the nail but the colour may vary from yellow to brown, depending on the aetiology. This area is sometimes malodorous.

In psoriasis (Figures 4.2-4.4) there is usually a yellow-red margin visible between the pink normal nail and the white separated area. In the 'oil spot' or 'salmon patch' variety, the separation between nail plate and nail bed may start in the middle of the nail; this is sometimes surrounded by a yellow margin, inflammatory and eczematous diseases affecting the nail bed. Oil patches have been reported in systemic lupus erythematosus; they may be extensive in lectitis purulenta et granulomatosa.

Onycholysis is usually symptomless. The extent of onycholysis increases progressively and can be estimated by measuring the distance separating the distal edge of the lunula from the proximal limit detachment, Transillumination of the terminal phalanx gives a good view of the affected area. The onset may be sudden in trauma (often of occupational origin) and in photo-onycholysis (Figure 4.5) where there may be a triad of photosensitiza-tion, onycholysis and dyschromia. Four distinct types of onycholysis (often preceded by onychodynia) were noted after both antibiotics and psoralens were administered; one common sign was prevalent in the first three types: the lateral margins of the nails were unaffected.

Finger Tophus And Nail Deformities

Figure 4.1


especially in psoriasis. The accumulation of large amounts of serum-like exudate containing glycoprotein, in and under the affected nails, explains the colour change in this condition. Glycoprotein is also commonly found in

Soft Tissure Nail

Figure 4.2

Onycholysis with Pseudomonas aeruginosa discoloration.

Figure 4.2

Onycholysis with Pseudomonas aeruginosa discoloration.

Separation The Nail Plate

Figure 4.3

Onycholysis—showing the separation of the nail plate and nail bed.

Figure 4.3

Onycholysis—showing the separation of the nail plate and nail bed.

Figure 4.4

Onycholysis due to psoriasis.

Figure 4.5


Figure 4.6

Self-induced onycholysis.

• Type I: several fingers are involved; the separating part of the nail plate is half-moon-shaped and concave distally with a pigmentation of variable intensity, and shows a well-demarcated proximal border.

• Type II: one finger only is affected; a well-defined circular notch is present, which opens distally and has a brownish hue proximally.

• Type III: in the central part of the pink nail bed on several fingers, there is initially a round yellow staining that turns reddish after 5-10 days.

• Type IV: bullae under the nails have been reported in photo-onycholysis due to tetracycline hydrochloride and in four types of cutaneous porphyria—porphyria cutanea tarda, erythropoietic porphyria, erythropoietic protoporphyria and variegate porphyria—as well as in pseudo-porphyria.

Sudden onset of oncycholysis may also be due to contact with chemical irritants such as hydrofluoric acid or hair remover containing thioglycolate. In finger nails, irregularly sculptured onycholysis is a self-induced nail abnormality due to excessive manicure with a sharp instrument (Figure 4.6). Sometimes the proximal lytic border is straight or gently curved.

Onycholysis of the toe demonstrates some differences from the condition on the fingers: the major distinctions are due to:

• The lack of occupational causes.

• The reduced use of cosmetics on the toes.

• The protection afforded by footwear (photo-onycholysis is rare).

The two main causes of onycholysis of the toe nail, especially the great toe nail, are onychomycosis and traumatic onycholysis. Onycholysis of the great toe nail is often seen when the second toe overrides it. Other causes

Finger nail onycholysis as an isolatd sign on a few nails in adult women is often perpetuted by overzealous maincurring

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