**6. Clinical lesions of nail psoriasis**

Psoriasis patients with nail involvement have a longer disease duration, higher disease severity, more than double the frequency of psoriatic arthritis, more pronounced impairment of disease related quality of life, they were statistically significantly longer off work, and had a 2.5 fold higher rate of in-hospital treatments (Augustin et al, 2010).

Nail psoriasis is characterized by pits, salmon spots, onycholysis, subungual hyperkeratosis and some more signs that are less frequent. The psoriatic nail changes may be classified according to their origin: Pitting, leukonychia, nail plate thickening, crumbling and red spots in the lunula originate in the matrix whereas oil drop discoloration (salmon spots), nail bed hyperkeratosis, onycholysis and splinter haemorrhages derive from the nail bed. Swelling of the proximal nail fold reflects paronychia and swelling of the distal interphalangeal joint is suggestive of psoriatic arthritis. Psoriatic pachydermoperiostosis leads to enlargement of the entire distal phalanx.

Nail Psoriasis 153

b) Fig. 12. a - c. 16-year-old boy with marked nail psoriasis. Note that some nails are almost

transverse rows. Longitudinal rows of pits are due to repeated minor trauma at exactly the same location of the proximal matrix whereas transverse ones may reflect a trauma that elicited a Köbner phenomenon at many spots at the same time. Rarely, shallow transverse lines are seen indicating a microtrauma to the entire width of the matrix. The variable arrangement of the pits may cause a clinical picture that varies within a relatively short period of time. It is now thought that pits may be due to microtrauma of the proximal matrix, which is the closest to the articulation, from the distal interphalangeal joint. Pits in

In pustular psoriasis, pits may occur that are much larger than usual pits (Fig. 14); they are

Salmon or oil spots represent circumscribed psoriasis plaques of the nail bed. Their specific colour is due to the fact that the psoriatic scales are compressed under the nail plate and imbibed with serum that makes them appear yellowish-reddish mimicking a drop of oil on a sheet of paper. Once a psoriatic plaque has reached the hyponychium or when it started at the hyponychium the scales are not or no longer compressed by the overlying nail plate and

destroyed, other are much less involved.

also called elkonyxis.

horizontal rows are equivalent to Beau's lines (Fig. 13).

may break out giving rise to onycholysis (Fig 15).

a) b)

Fig. 11. Psoriatic pits are small depressions of the nail surface of equal size and depth. The pits in a are artificially stained by dithranol treatment, b shows distal onycholysis in addition.

Analogous lesions are small white to yellowish spots that are mainly seen in the proximal nail plate when the parakeratosis does not break off the plate. This is called spotted nails (Tüpfelnägel in German), a term not commonly used in the Anglo-American literature. A number of ten or more pits per nail or more than 60 pits in all nails is commonly seen as proof of psoriasis (Baran & Haneke, 2007). Both pits and spots derive from tiny lesions in the most proximal matrix and possibly the most proximal part of the ventral surface of the proximal nail fold (Zaias, 1990). The length of a pit represents the length of time of the psoriatic matrix lesion, its width is indicative of the width of the lesions and the depth either of the severity of the lesion or a lesion that extends a bit into the intermediate matrix. Pits are usually arranged irregularly but sometimes they form longitudinal or even

Pits are generally said to be the most frequent signs. They are small, well delimited depressions on the surface of the nail plate with usually equal size and depth (Figs 11-12).

Pits are generally said to be the most frequent signs. They are small, well delimited depressions on the surface of the nail plate with usually equal size and depth (Figs 11-12).

b) Fig. 11. Psoriatic pits are small depressions of the nail surface of equal size and depth. The pits in a are artificially stained by dithranol treatment, b shows distal onycholysis in

Analogous lesions are small white to yellowish spots that are mainly seen in the proximal nail plate when the parakeratosis does not break off the plate. This is called spotted nails (Tüpfelnägel in German), a term not commonly used in the Anglo-American literature. A number of ten or more pits per nail or more than 60 pits in all nails is commonly seen as proof of psoriasis (Baran & Haneke, 2007). Both pits and spots derive from tiny lesions in the most proximal matrix and possibly the most proximal part of the ventral surface of the proximal nail fold (Zaias, 1990). The length of a pit represents the length of time of the psoriatic matrix lesion, its width is indicative of the width of the lesions and the depth either of the severity of the lesion or a lesion that extends a bit into the intermediate matrix. Pits are usually arranged irregularly but sometimes they form longitudinal or even

addition.

a)

Fig. 12. a - c. 16-year-old boy with marked nail psoriasis. Note that some nails are almost destroyed, other are much less involved.

b)

transverse rows. Longitudinal rows of pits are due to repeated minor trauma at exactly the same location of the proximal matrix whereas transverse ones may reflect a trauma that elicited a Köbner phenomenon at many spots at the same time. Rarely, shallow transverse lines are seen indicating a microtrauma to the entire width of the matrix. The variable arrangement of the pits may cause a clinical picture that varies within a relatively short period of time. It is now thought that pits may be due to microtrauma of the proximal matrix, which is the closest to the articulation, from the distal interphalangeal joint. Pits in horizontal rows are equivalent to Beau's lines (Fig. 13).

In pustular psoriasis, pits may occur that are much larger than usual pits (Fig. 14); they are also called elkonyxis.

Salmon or oil spots represent circumscribed psoriasis plaques of the nail bed. Their specific colour is due to the fact that the psoriatic scales are compressed under the nail plate and imbibed with serum that makes them appear yellowish-reddish mimicking a drop of oil on a sheet of paper. Once a psoriatic plaque has reached the hyponychium or when it started at the hyponychium the scales are not or no longer compressed by the overlying nail plate and may break out giving rise to onycholysis (Fig 15).

Nail Psoriasis 155

there may also be a thickening of the nail plate itself. Clinically this looks like a rough nail with irregular surface and loss of transparency, which is mainly due to wavy arrangement

Fig. 14. Nail involvement in pustular psoriasis of the palms and soles (Barber-Königsbeck type). Note the relatively large pits and some ivory-coloured spots. These large surface

Small dark-brown to black longitudinal streaks in the nail bed, mainly in distal location, are called splinter haemorrages (Fig 16). They are due to thromboses of the dilated capillaries of the nail bed papillary ridges, which run all along the nail bed with 3 to 5 layers of capillaries

Psoriatic leukonychia is relatively rare. It usually represents a focus of parakeratosis in the intermediate nail layers. It is often associated with other signs of nail psoriasis and may be

Larger psoriatic lesions of the nail matrix cause crumbly nails, even complete nail

Pustular psoriasis of the nails is seen in palmar plantar pustular psoriasis of Barber-Königsbeck (Figures 14, 17), in generalized pustular psoriasis of von Zumbusch and in Hallopeau's acrodermatitis continua suppurativa. In palmar plantar pustular psoriasis, nail involvement is commonly seen as yellow lakes of pus under the nail plate. This is often associated with elkonyxis. In generalized pustular psoriasis, nail involvement usually leads

depressions are called elkonyxis.

seen as an advancing edge in acute-onset nail psoriasis.

destruction. They are often associated with psoriatic arthritis.

one above the other.

to nail dystrophy.

of the nail lamellae as well as inclusion of serum and neutrophilic abscesses.

Small lesions in the intermediate and distal matrix may appear as red spots whereas extensive lesions may cause a red lunula before the resultant nail plate changes obscure these alterations.

Fig. 13. Pits arranged in horizontal rows. On finger nails, which grow faster they are still identifiable as single pits (A) whereas on toenails, due to their slow growth rate they appear as transverse furrows and lines (B).

Sometimes, psoriasis of the nail bed may cause important hyperkeratosis that may in extreme cases resemble pachyonychia congenita. In addition to subungual hyperkeratosis

Small lesions in the intermediate and distal matrix may appear as red spots whereas extensive lesions may cause a red lunula before the resultant nail plate changes obscure

a)

b) Fig. 13. Pits arranged in horizontal rows. On finger nails, which grow faster they are still identifiable as single pits (A) whereas on toenails, due to their slow growth rate they appear

Sometimes, psoriasis of the nail bed may cause important hyperkeratosis that may in extreme cases resemble pachyonychia congenita. In addition to subungual hyperkeratosis

as transverse furrows and lines (B).

these alterations.

there may also be a thickening of the nail plate itself. Clinically this looks like a rough nail with irregular surface and loss of transparency, which is mainly due to wavy arrangement of the nail lamellae as well as inclusion of serum and neutrophilic abscesses.

Fig. 14. Nail involvement in pustular psoriasis of the palms and soles (Barber-Königsbeck type). Note the relatively large pits and some ivory-coloured spots. These large surface depressions are called elkonyxis.

Small dark-brown to black longitudinal streaks in the nail bed, mainly in distal location, are called splinter haemorrages (Fig 16). They are due to thromboses of the dilated capillaries of the nail bed papillary ridges, which run all along the nail bed with 3 to 5 layers of capillaries one above the other.

Psoriatic leukonychia is relatively rare. It usually represents a focus of parakeratosis in the intermediate nail layers. It is often associated with other signs of nail psoriasis and may be seen as an advancing edge in acute-onset nail psoriasis.

Larger psoriatic lesions of the nail matrix cause crumbly nails, even complete nail destruction. They are often associated with psoriatic arthritis.

Pustular psoriasis of the nails is seen in palmar plantar pustular psoriasis of Barber-Königsbeck (Figures 14, 17), in generalized pustular psoriasis of von Zumbusch and in Hallopeau's acrodermatitis continua suppurativa. In palmar plantar pustular psoriasis, nail involvement is commonly seen as yellow lakes of pus under the nail plate. This is often associated with elkonyxis. In generalized pustular psoriasis, nail involvement usually leads to nail dystrophy.

Nail Psoriasis 157

Fig. 16. Splinter haemorrhages in a nail with salmon spot

Fig. 17. Psoriasis pustulosa of Barber-Königsbeck

Fig. 18. Early acrodermatitis continua suppurativa

Acrodermatitis continua suppurativa of Hallopeau is an insidiously developing disease of the tip of the finger commonly commencing dorsally and slowly involving the nail apparatus (Figs. 18, 19 a, b). The diagnosis is often only made late when there is already a certain degree of nail dystrophy. In very typical cases, the finger or toe tip rounds up, loses its nail, the skin is fiercely red with some tiny pustules. Radiographically, resorption of the corona unguicularis becomes evident. In acute cases, the skin may appear superficially necrotic.

b) Fig. 15. Subungual hyperkeratosis in distal nail bed psoriasis. A. Fingernails, B toe nails.

Acrodermatitis continua suppurativa of Hallopeau is an insidiously developing disease of the tip of the finger commonly commencing dorsally and slowly involving the nail apparatus (Figs. 18, 19 a, b). The diagnosis is often only made late when there is already a certain degree of nail dystrophy. In very typical cases, the finger or toe tip rounds up, loses its nail, the skin is fiercely red with some tiny pustules. Radiographically, resorption of the corona unguicularis

becomes evident. In acute cases, the skin may appear superficially necrotic.

a)

Fig. 16. Splinter haemorrhages in a nail with salmon spot

Fig. 17. Psoriasis pustulosa of Barber-Königsbeck

Fig. 18. Early acrodermatitis continua suppurativa

Nail Psoriasis 159

Fig. 20. Psoriatic paronychia in a patient with psoriasis arthropathy.

interphalangeal joint and a shiny skin.

detect changes not seen clinically (Khan et al, 2003).

nail plate.

**7. Quality of life** 

and Cooper, 2009).

**7.1 Scoring of nail psoriasis** 

Psoriatic enthesitis of the distal interphalangeal joint is a painful inflammation of the insertions of tendons and ligaments mainly at the base of the distal phalanx. This may cause swelling of the distal joint with stiffness and loss of the dorsal creases of the distal

Psoriatic pachydermoperiostosis is a rare event. It is associated with bone appositions which also lead to a widening of the base of the distal phalanx with consecutive widening of the

In almost a quarter of the patients with latent psoriatic arthritis, radiological assessment will

Nail psoriasis has been shown to severely impair quality of life (see Scoring of nail psoriasis). Pain, cosmetic embarrassment, impaired function, loss of dexterity are just some of the complaints brought forward by the patients (De Jong et al, 1996). More than 90% of the patients consider their nail psoriasis to be a significant social problem affecting their professional work, and more than half of them experienced pain (de Berker, 2009, Gupta

To score the extent and severity of nail psoriasis the **nail psoriasis severity index** (NAPSI) was developed (Rich and Scher, 2003). Each nail is divided into 4 quadrants by a horizontal

Fig. 19. Acrodermatitis continua suppurativa. A. Pustules have been present for more than 12 years in this elderly lady. B. Relatively acute onset of acrodermatitis continua suppurativa in a patient with bronchial carcinoma; whether this is a causal or accidental association is not clear.

Psoriatic paronychia develops when the periungual skin is affected by psoriasis, but it is also commonly seen in psoriatic arthritis with nail involvement (Fig. 20). The chronic inflammation causes thickening of the free edge of the proximal nail fold with consecutive loss of the cuticle and later loss of attachment of the nail fold's ventral surface to the underlying nail plate. This allows foreign material such as dirt, microorganisms or allergenic substances to enter the space under the nail fold where they may aggravate the inflammation.

b) Fig. 19. Acrodermatitis continua suppurativa. A. Pustules have been present for more than

Psoriatic paronychia develops when the periungual skin is affected by psoriasis, but it is also commonly seen in psoriatic arthritis with nail involvement (Fig. 20). The chronic inflammation causes thickening of the free edge of the proximal nail fold with consecutive loss of the cuticle and later loss of attachment of the nail fold's ventral surface to the underlying nail plate. This allows foreign material such as dirt, microorganisms or allergenic substances to enter the space

suppurativa in a patient with bronchial carcinoma; whether this is a causal or accidental

12 years in this elderly lady. B. Relatively acute onset of acrodermatitis continua

under the nail fold where they may aggravate the inflammation.

association is not clear.

a)

Fig. 20. Psoriatic paronychia in a patient with psoriasis arthropathy.

Psoriatic enthesitis of the distal interphalangeal joint is a painful inflammation of the insertions of tendons and ligaments mainly at the base of the distal phalanx. This may cause swelling of the distal joint with stiffness and loss of the dorsal creases of the distal interphalangeal joint and a shiny skin.

Psoriatic pachydermoperiostosis is a rare event. It is associated with bone appositions which also lead to a widening of the base of the distal phalanx with consecutive widening of the nail plate.

In almost a quarter of the patients with latent psoriatic arthritis, radiological assessment will detect changes not seen clinically (Khan et al, 2003).
