Jean Luc Drap MD PhD

Professor of Radiology, Hôpital Cochin, University of Paris Paris, France

A ypï Martin Dunitz

LvLy Ti^e-iriAfU Ciwn»


© 1990, 1996, 2003, Martin Dunitz, a member of the Taylor & Francis Group

First published in the United Kingdom in 1990 by Martin Dunitz, Taylor & Francis Group plc, 11 New Fetter Lane, London EC4P 4EE

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List of contributors vii

Preface x

1 Science of the nail apparatus

Rodney PR Dawber 1

2 Nail configuration abnormalities

Antonella Tosti, Robert Baran, Rodney PR Dawber, Eckart

Haneke 10

3 Modifications of the nail surface

Antonella Tosti, Robert Baran, Rodney PR Dawber, Eckart

Haneke 59

4 Nail plate and soft tissue abnormalities

Robert Baran, Rodney PR Dawber, Eckart Haneke, Antonella

Tosti 87

5 Periungual tissue disorders

Robert Baran 114

6 Nail consistency

Robert Baran, Rodney PR Dawber, Eckart Haneke, Antonella

Tosti 166

7 Nail colour changes (chromonychia)

Eckart Haneke, Robert Baran, Rodney PR Dawber, Antonella

Tosti 175

8 Onychomycosis and its treatment

Antonella Tosti, Robert Baran, Rodney PR Dawber, Eckart

Haneke 197

9 Traumatic disorders of the nail

Rodney PR Dawber and Ivan Bristow 221

10 Histopathology of common nail conditions

Eckart Haneke 268

11 Ultrasonography and magnetic resonance imaging of the perionychium

Jean-Luc Drapé, Sophie Goettmann, Alain Chevrot and Jacques Bittoun 280

12 Dermatoscopy of nail pigmentation

Luc Thomas and Sandra Ronger 302

13 Treatment of common nail disorders

Antonella Tosti, Robert Baran, Rodney PR Dawber, Eckart

Haneke 314

Index 327

List of contributors

Robert Baran MD

Nail Disease Centre 42 rue des Serbes 06400 Cannes, France

Jacques Bittoun MD, PhD

Centre Inter Etablissements de Resonance

Magnétique (CIERM)

CHU de Bicêtre

Université Paris Sud

74 rue du general Leclerc

94274 Le Kremlin-Bicêtre Cedex, France

Ivan Bristow, MSc, BSc, DPodM, MChS School of Podiatry University College of Northampton Park Campus

Northampton NN2 7AL, UK

Alain Chevrot, MD

Service de Radiologie B Hôpital Cochin

27 rue du Faubourg Saint-Jacques 75679 Paris Cedex 14, France

Rodney PR Dawber, MA, MB ChB, FRCP Department of Dermatology Churchill Hospital Old Road

Oxford OX3 7LJ, UK

Service de Radiologie B Hôpital Cochin

27 rue du faubourg Saint-Jacques 75679 Paris Cedex 14, France

Sophie Goettmann, MD

Service de Dermatologie

Hôpital Bichat 46 rue Henri Huchard 75018 Paris, France

Eckart Haneke, MD

Klinikk Bunaes Lokkeâsveien 3 1300 Sandvika/Oslo, Norway

Sandra Ronger, MD, PhD

Unite Dermatologique Hotel Dieux

69288 Lyon Cedex 02, France

Luc Thomas, MD, PhD

Unite Dermatologique Hôtel Dieux

69288 Lyon Cedex 02, France

Antonella Tosti, MD

Istituto di Clinica Dermatologica Université di Bologna Policlinico S Orsola Via G Massarenti 1 40138 Bologna, Italy


The editorial team were reassured that the second edition, with its differential diagnostic style of presenting clinical information together with liberal use of colour illustrations, had been successful enough to merit a further edition. Seven years have passed since the previous edition and evidently, like for other areas of clinical medicine, diagnostic and therapeutic advances have been made in relation to nail disorders. These are reflected in this third edition.

The science of the nail apparatus and the clinical management of the foot and traumatic nail disorders are now much more closely allied to podiatry and this is shown in the contributions of Ivan Bristow and by his inclusion as a member of the editorial team.

Until relatively recently only mycological and histological diagnostic routines were used to investigate nail diseases. Luc Thomas and Sandra Ronger have contributed a new section on the use of dermatoscopy in the nail and periungual tissues, reflecting the increasing subtlety of this technique in the diagnosis of pigmentary conditions.

Ultrasonography and Magnetic Resonance Imaging (MRI) have become very important in diagnosis and presurgical assessment and a contribution by JeanLuc Drape shows the advances in this field.

Many of our dermatological and podiatric colleagues use this book as their main diagnostic tool and to further aid our readers we have increased the number of 'further reading' references throughout the book.

Robert Baran Rodney PR Dawber Eckart Haneke Antonella Tosti Ivan Bristow January 2003

Science of the nail apparatus

Rodney PR Dawber


Microscopic anatomy Blood and nerve supply Nail dynamics

The nails in childhood and old age

The anatomy and physiology of the nail apparatus on the hand may be considered in isolation; however, the nail apparatus on the toes must always be considered in relation to toe and foot structure and function. Many disorders of nails are directly due to functional faults in the foot; alternatively, diseases of the nail apparatus may be modified by alterations in digital or foot shape or movement (see Chapter 9).

The nail is an important 'tool' and adds subtlety and protection to the digit.

The nail apparatus develops from the primitive epidermis. Its main function is to produce a strong, relatively inflexible nail plate over the dorsal surface of the end of each digit. The nail plate acts as a protective covering for the digit by exerting counter-pressure over the volar skin and pulp; its relative flatness adds to the precision and delicacy of the ability to pick up small objects and of many other subtle finger functions. Counter-pressure against the plantar skin and pulp prevents the 'heaping up' of the distal soft tissue. Finger nails typically cover approximately one-fifth of the dorsal surface, while on the great toe, the nail may cover up to half of the dorsum of the digit. Toe nails and finger nails have varying shapes and curvature. This is controlled by many factors: the area of the proximal matrix; the rate of cell division within it; and the shape of the underlying distal phalanx to which the nail is firmly attached by vertical connective tissue.


The component parts of the nail apparatus are shown in Figure 1.1. The rectangular nail plate is the largest structure, resting on and firmly attached to the nail bed and the underlying bones; it is less firmly attached proximally, apart from the posterolateral corners. Approximately one-quarter of the nail is covered by the proximal nail fold, while a narrow margin of the sides of the nail plate is often occluded by the lateral nail folds. Underlying the proximal part of the nail is the white lunula ('half-moon' or lunule); this area represents the most distal region of the matrix. The natural shape of the free margin of the nail is the same as the contour of the distal border of the lunula. The nail plate distal to the lunula is usually pink owing to its translucency, which allows the redness of the vascular nail bed to be seen through it. The proximal nail fold has two epithelial surfaces, dorsal and ventral; at the junction of the two the cuticle projects distally on to the nail surface. The lateral nail folds are in continuity with the skin on the sides of the digit laterally, and medially they are joined by the nail bed.

The nail matrix can be subdivided into proximal (or dorsal) and distal (or intermediate) sections, the latter underlying the nail plate to the distal border of the lunula. It is now generally considered that the nail bed contributes to the deep surface of the nail plate (ventral matrix), although this thin, soft, deep component plays little part in the functional integrity of the nail plate in its distal part. At the point of separation of the nail plate from the nail bed, the proximal part of the hyponychium may be modified as the solehorn. In hooved animals this is the site of hard keratin hoof formation—it may also be the source of hard, distal subungual hyperkeratosis in diseases such as psoriasis and pachyonychia congenita. Beyond the solehorn region the hyponychium terminates at the distal nail groove; the tip of the digit beyond this ridge assumes the structure of the epidermis elsewhere.

When the attached nail plate is viewed from above, several distinct areas may be visible, such as the proximal lunula and the larger pink zone. On close examination two further distal zones can often be identified: the distal yellowish-white margin, and immediately proximal to this the onychodermal band. The latter is a barely perceptible, narrow transverse band 0.5-1.5 mm wide. The exact anatomical basis for the onychodermal (onychocorneal) band is not known but it appears to have a separate blood supply from that of the main body of the nail bed; if the tip of the finger is pressed firmly, the band and an area just proximal to it blanch, and if the pressure is repeated several times the band reddens.

Onychocorneal Band

Figure 1.1

(a), (b) Nail apparatus structures; (c) longitudinal nail biopsy section, oriented to equate with (b).


The proximal nail fold is similar in structure to the adjacent skin but is normally devoid of dermatoglyphic markings and sebaceous glands. From the distal area of the proximal nail fold the cuticle reflects on to the surface of the nail plate. The cuticle is composed of modified stratum corneum and serves to protect the structures at the base of the nail, particularly the germinative matrix, from environmental insults such as irritants, allergens and bacterial and fungal pathogens.

Nail matrix

The proximal (dorsal) and distal (intermediate) nail matrix produces the major part of the nail plate. Like the epidermis of the skin, the matrix possesses a dividing basal layer producing keratinocytes; these differentiate, harden, die and contribute to the nail plate, which is thus analogous to the epidermal stratum corneum. The nail matrix keratinocytes mature and keratinize without keratohyalin (granular layer) formation. Apart from this, the detailed cytological changes seen in the matrix epithelium under the electron microscope are essentially the same as in the epidermis.

The nail matrix contains melanocytes in the lowest two cell layers and these donate pigment to keratinocytes. Under normal circumstances pigment is not visible in the nail plate of white individuals, but many black people show patchy melanogenesis as linear longitudinal pigmented bands.

On the great toes, the nail matrix sits like a saddle on the distal phalanx

Nail bed

The nail bed consists of an epidermal part and an underlying dermal part closely apposed to the periosteum of the distal phalanx. There is no subcutaneous fat layer in the nail bed, although scattered dermal fat cells may be visible microscopically. The epidermal layer is usually no more than two or three cells thick, and the transitional zone from living keratinocyte to dead ventral nail plate cell is abrupt, occurring in the space of one horizontal cell layer. As the cells differentiate they are incorporated into the ventral surface of the nail plate and move distally with this layer.

The nail bed dermal fibrous tissue network is mainly oriented vertically, being directly attached to phalangeal periosteum and the epidermal basal lamina. Within the connective tissue network lie blood vessels, lymphatics, a fine network of elastic fibres and scattered fat cells; at the distal margin, eccrine sweat glands have been seen.

Nail plate

The nail plate is composed of three horizontal layers: a thin dorsal lamina, the thicker intermediate lamina and a ventral layer from the nail bed. Microscopically it consists of flattened, dead squamous cells closely apposed to each other. In older people acidophilic masses are occasionally seen, called 'pertinax bodies'.

The nail plate is rich in calcium, found as the phosphate in hydroxyapatite crystals; it is bound to phospholipids intracellularly. The relevance of other elements which are present in smaller amounts, such as copper, manganese, zinc and iron, is not exactly known. Calcium exists in a concentration of 0.1% by weight, 10 times greater than in hair. Calcium does not significantly contribute to the hardness of the nail. Nail hardness is mainly due to dense sulphur protein from the matrix, which contrasts with the relatively soft keratin of the epidermis. The normal curvature of the nail relates to the shape of the underlying phalangeal bone to which the nail plate is directly bonded via the vertical connective tissue attachment between the subungual epithelium and the periosteum.

Science of the nail apparatus 5 BLOOD AND NERVE SUPPLY

The nail apparatus has a magnificent blood supply with many anasomoses

There is a rich arterial blood supply to the nail bed and matrix derived from paired digital arteries (Figure 1.2). The main supply passes into the pulp space of the distal phalanx before reaching the dorsum of the digit. The volar digital nerves (Figure 1.2c) are similarly important in providing nerves to the deep nail apparatus structures. An accessory blood supply arises further back on the digit and does not enter the pulp space. There are two main arterial arches (proximal and distal) supplying the nail bed and matrix, formed from anastomoses of the branches of the digital arteries. In the event of damage to the main supply in the pulp space, such as might occur with trauma, infection or scleroderma, there may be sufficient blood from the accessory vessels to permit normal growth of the nail.

There is a capillary loop system to the whole of the nail fold, but the loops to the roof and matrix are flatter than those below the exposed nail. There are many arteriovenous anastomoses below the nail—glomus bodies, which are concerned with heat regulation. Glomus bodies are important in maintaining acral circulation under cold conditions— arterioles constrict with cold, but glomus bodies dilate. The nail beds of fingers and toes contain such bodies (93-501 per cm2). Each glomus is an encapsulated oval organ 300 ^m long, made up of a tortuous vessel uniting an artery and venule, a nerve supply and a capsule; also within the capsules are many cholinergic muscle cells.


Clinicians used to observing the slow rate of clearance of diseased or damaged nails are apt to view the nail apparatus as a rather inert structure, although it is in fact the centre of marked kinetic and biochemical activity.

Cell kinetics

Unlike the hair matrix, which undergoes a resting or quiescent (telogen) phase every few years, the nail matrix germinative layers continue to undertake DNA synthesis, to divide and to differentiate throughout life, akin to the epidermis in this respect. Exactly which parts of the nail apparatus contribute to the nail plate has been debated; it is now usually accepted that the three-layer nail plate is produced from the proximal matrix, the distal matrix and the nail bed (sterile ventral matrix).

Nail Plate Upper Layer Onychomycosis

Figure 1.2

Digital blood and nerve supply: (a) showing arterial anastomoses; (b) arterial supply from hand to digits (radio-opaque dye seen in arterises); (c) major digital arteries and nerve supply.

Ytbr njidil m«

Figure 1.2

Digital blood and nerve supply: (a) showing arterial anastomoses; (b) arterial supply from hand to digits (radio-opaque dye seen in arterises); (c) major digital arteries and nerve supply.

The nail grows continuously througout life

Why the nail grows flat, rather than as a heaped-up keratinous mass, has generated much thought and discussion. Several factors probably combine to produce a relatively flat nail plate; the orientation of the matrix rete pegs and papillae, the direction of cell differentiation, and the fact that since keratinization takes place within the confines of the nail base, limited by the proximal nail fold dorsally and the terminal phalanx ventrally, the differentiating cells can only move distally and form a flat structure—by the time they leave the confines of the proximal nail fold all the cells are dead, keratinized and hardened.

Linear nail growth

Many studies have investigated the linear growth rates of the nail plate in health and disease; their findings are summarized in Tables 1.1 and 1.2. Finger nails grow

Science of the nail apparatus 7 approximately 1 cm every 3 months and toe nails at half this rate.

Table 1.1 Physiological and environmental factors affecting the rate of linear _nail growth_

Faster growth

Slower growth

Day-time Pregnancy

Minor trauma/nail biting Right-hand nails Youth, increasing age Fingers Summer

Middle, ring and index fingers Male (?)_

Night-time First day of life

Left-hand nails Old age Toes

Winter or cold environment Thumb and little finger Female (?)_



In early childhood, the nail plate is thin and may show temporary koilonychia. Because of the shape of the matrix, some children show ridges that start laterally by the proximal nail fold and join at a central point just short of the free margin, to give a 'herringbone' arrangement of the ridges (chevron nails). In one study 92% of normal infants aged 8-9 weeks showed a single transverse line (Beau's line) on the finger nails. One child demonstrated a transverse depression through the whole nail thickness on all 20 digits.

Old age

Many of the changes seen in old age may occur in younger age groups with impaired arterial blood supply. Elastic tissue changes diffusely affecting the nail bed epidermis are often seen historically; these changes may be due to the effects of ultraviolet (UV) radiation, although it has been stated that the nail plate is an efficient filter of UVB radiation. The whole subungual area in old age may show thickening of blood vessel walls with vascular elastic tissue fragmentation. Pertinax bodies are often seen in the nail plate; they are probably remnants of nuclei of keratinocytes. Nail growth is inversely proportional to age; related to this slower growth, corneocytes are larger in old age. Since nails tend to thicken with age and some diseases, it may well be that the volume of nail production per unit of time does not change.

The nail plate becomes paler, dull and opaque with advancing years and white nails similar to those seen in cirrhosis, uraemia and hypoalbuminaemia may be seen in normal individuals. Longitudinal ridging is present to some degree in most people after 50 years of age and this may give a 'sausage links' appearance.

Table 1.2 Pathological factors affecting the rate of linear nail growth

Faster growth_Slower growth

Table 1.2 Pathological factors affecting the rate of linear nail growth

Faster growth_Slower growth


Finger immobilization

normal nails



Beau's lines



Pityriasis rubra pilaris

Poor nutrition

Idiopathic onycholysis of women


Bullous ichthyosiform erythroderma



Yellow nail syndrome


Relapsing polychondritis

Arteriovenous shunts

Nail configuration abnormalities

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

Clubbing (Hippocratic fingers) Koilonychia

Transverse overcurvature

Dolichonychia (long nails)

Brachyonychia (short nails)

Parrot-beak nails

Round fingerpad

Hook and claw-like nails

Micronychia, macronychia and polydactyly

Worn-down, shiny nails

Anonychia and onychatrophy

Further reading


The bulbous digital deformity known as clubbing (Figure 2.1a,b) was described as early as the fifth century BC when Hippocrates noted such changes in patients suffering from empyema. The diagnostic signs comprise:

1 Overcurvature of the nails in the proximal to distal and transverse planes (Figure 2.2).

2 Enlargement of periungual soft tissue structures confined to the tip of each digit.

A simple method to detect clubbing is measurement of the phalangeal depth ratio (Figure 2.3). In a normal finger the distal phalangeal depth is smaller than the interphalangeal depth. In clubbing this relationship is reversed (>1). The measurement can easily be taken using a caliper in less than a minute.


Figure 2.1

Figure 2.1

Nail Clubbing

Figure 2.2

Clubbing, demonstrating typical nail curvature and obliteration of the 'window'.

Figure 2.2

Clubbing, demonstrating typical nail curvature and obliteration of the 'window'.

Clubbed Finger Distal Depth
Figure 2.3 In clubbing the phalangeal depth ratio is greater than 1. (a/b>1)

The increased nail curvature usually affects all 20 digits, but may be particularly obvious on the thumbs, index and middle fingers. The 'watch-glass' shape of the nail may occur as an isolated deformity without any associated enlargement of the tip of the digit. The shape of the curved nails is variable and may appear fusiform, like a bird's beak, or clubbed like a watch-glass. The matrix quite often appears abnormally large. There are three main types of clubbing:

1 Simple clubbing.

2 Hypertrophic pulmonary osteoarthropathy.

3 Pachydermoperiostosis.

Simple clubbing

Simple clubbing is the most common category and has several distinctive characteristics:

1 Increased nail curvature occurs with a transverse furrow separating it from the rest of the nail both in the early stage and after resolution. The onset is usually gradual and painless, except in some cases of carcinoma of the lung in which clubbing may develop abruptly and be associated with severe pain.

2 Hypertrophy of the soft parts of the terminal segment caused by firm, elastic, oedematous infiltration of the pulp, which may spread to the dorsal surface with marked periungual swelling.

3 Hyperplasia of the dermal fibrovascular tissue may extend to involve the adjacent matrix. This accounts for one of the earliest signs of clubbing—abnormal mobility of the nail base, which can be rocked back and forth giving the impression that it is floating on a soft oedematous pad. The increased vascularity is responsible for the slow return of colour when the nail is pressed and released.

4 Acral cyanosis is often observed.

In the early stages clubbing may involve one hand only, though eventually both hands become affected symmetrically. Several stages of clubbing or acropachy may be distinguished: suspected, slight, average and severe. In practice the degree of the deformity may be gauged by Lovibond's 'profile sign' which measures the angle between the curved nail plate and the proximal nail fold when the finger is viewed from the radial aspect. This is normally 160°, but exceeds 180° in clubbing. A modified profile sign is assessed by measuring the angle between the middle and the terminal phalanx at the interphalangeal joint: in normal fingers the distal phalanx forms an almost straight (180°) extension of the middle phalanx, whereas in severe clubbing this angle may be reduced to 160° or even 140°. However, the best indicator may be the simple clinical method adopted by Schamroth: in normal individuals a distinct aperture or 'window', usually diamond-shaped, is formed at the base of the nail bed; early clubbing obliterates this window. (Fig 2.2).

Radiological changes occur in less than one-fifth of cases. These include phalangeal demineralization and irregular thickening of the cortical diaphysis. Ungual tufts generally show considerable variations and may be prominent in advanced stages of the disease. Bony atrophy may be present.

Congenital finger clubbing may be accompanied by changes such as hyperkeratosis of the palms and soles, and cortical hypertrophy of the long bones. Familial clubbing may be associated with hypertrophic osteoarthropathy; some authors regard simple clubbing as a mild form of the latter. Isolated watch-glass nails without other deformities are also constitutionally determined. Rare cases of unilateral Hippocratic nails have been reported due to obstructed circulation, oedema of the soft tissues and dystrophy of the affected parts. The pathological process apparently responsible for clubbing and its associated changes is the increased blood flow due to the opening of many anastomotic shunts.

Acquired clubbing almost always has an internal cause

Hypertrophic pulmonary osteoarthropathy

This disorder is characterized by the following five signs:

1 Clubbing of the nails.

2 Hypertrophy of the upper and lower extremities similar to the deformity found in acromegaly.

3 Joint changes with pseudo-inflammatory, symmetrical, painful arthropathy of the large limb joints, especially those of the legs. This syndrome is almost pathognomonic of malignant chest tumours, especially lung carcinoma and mesothelioma of the pleura; less commonly bronchiectasis is seen. Gynaecomastia may also be present.

4 There may be bone changes such as bilateral, proliferative periostitis and moderate, diffuse decalcification. 5 Peripheral neurovascular disorders such as local cyanosis and paraesthesia are not uncommon.

Hypertrophic osteoarthropathy confined to the lower extremities appears as a manifestation of arterial graft sepsis.


Pachydermoperiostosis (idiopathic hypertrophic osteoarthropathy) is rare. In most of the reported cases the digital changes typically begin at or about the time of puberty. The ends of the fingers and toes are bulbous and often grotesquely shaped, with hyperhidrosis of the hands and the feet (Figure 2.4). The clubbing stops abruptly at the distal interphalangeal joint. In this type the lesions of the finger tips are clinically identical to those of hypertrophic pulmonary osteoarthropathy. However, in pachydermoperiostosis the thickened cortex appears homogeneous on X-ray examination and does not impinge on the medullary space. Acro-osteolysis of the distal phalanges has been reported.

Phalanx Radiological Examination

Figure 2.4

Clubbing in pachydermoperiostosis.

Figure 2.4

Clubbing in pachydermoperiostosis.

The pachydermal change of the extremities and face, with furrowing and oiliness of the skin, is the most characteristic feature of the disorder; it is termed the Touraine-Solente-Gole syndrome. Nevertheless, in hypertrophic pulmonary osteoarthropathy there may be facial skin and scalp changes indistinguishable from those seen in pachydermoperiostosis; this may be due to a common genetic factor. In the differential diagnosis acromegaly must be considered; this enhances tufting of the terminal phalanges and presents an anchor-like appearance, but without acro-osteolysis. Thyroid acropachy is usually associated with exophthalmos, pretibial myxoedema and abnormal thyroid function.

It should be noted that only rarely will any type of clubbing present to a dermatologist, since in most cases it is simply one sign among many relating to the primary cause.

Classification of clubbing

The principal general causes of clubbing are listed in Table 2.1; a more comprehensive list of causes is given below.

Hereditary and congenital forms, sometimes associated with other anomalies:

• familial and genotypic pachydermoperiostosis

• racial forms (Africans)

• syndrome of pernio, periostosis and lipodystrophy

• Muckle-Wells syndrome.

Table 2.1 General causes of clubbing and pseudoclubbing_

Clubbing Pseudoclubbing

Unilateral Yellow nail syndrome (Figure 2.7)

Aortic/subclavian aneurysm Gout

Brachial plexus injury Sarcoidosis

Trauma (Figure 2.5) Osteoid osteoma


Congenital familial/sporadic

Thoracic tumours (bronchopulmonary cancers)



Gastrointestinal inflammatory bowel disease parasitosis liver disease tropical sprue

Endocrine/metabolic thyroid, acromegaly (Figure 2.6)



Secondary to pulmonary and other infections

Idiopathic forms

Lower extremities Arterial graft sepsis

Perineurioma Metastases

Congenital abnormalities Chronic paronychia—severe hook nail

Acquired forms

1 Thoracic disorders are involved in about 80% of cases of clubbing, often with the common denominator of hypoxia:

• bronchopulmonary diseases, especially chronic and infective bronchiectasis, abscess and cyst of the lung, pulmonary tuberculosis

• sarcoidosis, pulmonary fibrosis, emphysema, Ayerza's syndrome, chronic pulmonary venous engorgement, asthma in infancy, mucoviscidosis

• blastomycosis, pneumonia, Pneumocystis carinii infection, AIDS.

2 Thoracic tumours:

• primary or metastatic bronchopulmonary cancers, pleural tumours, mediastinal tumours

• Hodgkin's disease, lymphoma, pseudotumour due to oesophageal dilatation.

Figure 2.5

Pseudoclubbing due to trauma—hooked nail deformity.

3 Cardiovascular disease:

• congenital heart disease associated with cyanosis (rarely non-cyanotic)

• thoracic vascular malformations; stenoses and arteriovenous aneurysms

• Osler's disease (subacute bacterial endocarditis)

• congestive cardiac failure

• Raynaud's disease, erythromelalgia, Maffucci's syndrome.

4 Disorders of the alimentary tract (5% of cases):

Hooked Nail

Figure 2.5

Pseudoclubbing due to trauma—hooked nail deformity.

oesophageal, gastric and colonic cancer

Nail configuration abnormalities 17 • disease of the small intestine

Nail Deformity Causes

Figure 2.6

Clubbed appearance in acromegaly. (Courtesy of D.Wendling.)

Figure 2.6

Clubbed appearance in acromegaly. (Courtesy of D.Wendling.)

Acromegaly Hand Ray

Figure 2.7

Pseudoclubbing in yellow nail syndrome.

Figure 2.7

Pseudoclubbing in yellow nail syndrome.

• colonic disease

• amoebiasis and inflammatory states of the colon

• ulcerative colitis

• familial polyposis, Gardner's syndrome

• ascariasis

• active chronic hepatitis

• primary or secondary cirrhoses

• purgative abuse.

5 Endocrine origin:

• Diamond's syndrome (pretibial myxoedema, exophthalmos and finger clubbing)

6 Haematological causes:

• methaemoglobinaemia

• sulphaemoglobinaemia

• haemoglobinopathies

• primary or secondary polycythaemia associated with hypoxia

• poisoning by phosphorus, arsenic, alcohol, mercury or beryllium.

7 Hypervitaminosis A.

8 Malnutrition, kwashiorkor.

9 Addiction (hashish, heroin).

10 Syringomyelia, POEMs syndrome (peripheral neuropathy, organomegaly, endocrinopathy, monoclonal plasmaproliferative disease, skin changes).

11 Lupus erythematosus.

12 Unilateral or limited to a few digits:

• subluxation of the shoulder (with paralysis of the brachial plexus), medial nerve neuritis

• Pancoast-Tobias syndrome

• aneurysm of the aorta or the subclavian artery

• sarcoidosis

• tophaceous gout.

13 Lower extremities:

• arterial graft sepsis.

14 Isolated forms:

• local injury, whitlow, lymphangitis

• subungual epidermoid inclusions.

15 Transitory form: physiological in the newborn child (due to reversal of the circulation at birth).

16 Occupational acro-osteolysis (exposure to vinyl chloride).


Koilonychia (spoon-shaped nails) is the opposite of clubbing. The nail is firmly attached to bone by vertical dermal connective tissue bundles in the subungual area which bond directly to the bony periosteum. In the early stages of koilonychia there is flattening of the nail plate. Later, the edges become everted upwards and the nail appears concave, giving rise to the characteristic 'spoon' shape (Figures 2.8-2.11). In mild cases the water test may enable a drop of water to be retained on the nail plate. The subungual tissues may be normal, or affected by hyperkeratosis at the lateral and/or the distal margin.

Koilonychia is more often due to local rather than systemic factors

1 In neonates and in infancy, koilonychia is a temporary physiological condition (Figures 2.12, 2.13). There is a proven correlation between koilonychia and iron deficiency (with normal haemoglobin values) in infants.

2 Koilonychia is a common manifestation of the rare Plummer-Vinson syndrome in association with anaemia, dysphagia and glossitis.

3 When subungual keratosis accompanies koilonychia, psoriasis should be considered, as well as occupational causes, which may be relevant in those who work with cement, or in car mechanics whose hands suffer constant immersion in oil, for example.

4 Koilonychia may result from thin nails of any cause (old age, peripheral arterial disease and so on).

Concave Shaped Fingernails

Figure 2.8

Koilonychia or 'spoon-shaped' nail; thin nail variety.

Figure 2.8

Koilonychia or 'spoon-shaped' nail; thin nail variety.

Subungual Distal Hyperkeratosis

Figure 2.9

Koilonychia—distal view with some terminal traumatic whitening.

Figure 2.9

Koilonychia—distal view with some terminal traumatic whitening.

Goettmann Sophie Dermatologue

Figure 2.10

Koilonychia—severe variety, of many nails. Involvement of the first three nails is a plea for an occupational cause.

Figure 2.10

Koilonychia—severe variety, of many nails. Involvement of the first three nails is a plea for an occupational cause.

Longitudinal Transverse Nail

Figure 2.11

Koilonychia—transverse and longitudinal curvature evident.

Figure 2.11

Koilonychia—transverse and longitudinal curvature evident.

5 Soft nails of any cause (mainly occupational) may also cause this condition.

6 Hereditary and congenital forms (Figures 2.14-2.16) are sometimes associated with other nail signs such as leukonychia.

The most common causes of koilonychia are probably occupational softening and iron deficiency (Table 2.2) Occupational koilonychia is often associated with mild nail-plate surface abnormalities and nail plate discoloration.

Iron Deficiency Koilonychia Child

Figure 2.12

Koilonychia—temporary type of early infancy.

Figure 2.12

Koilonychia—temporary type of early infancy.

Finger Nail Decalcification

Figure 2.13

Physiological koilonychia and thinning in the toe nails of a 3-month-old infant.

Figure 2.13

Physiological koilonychia and thinning in the toe nails of a 3-month-old infant.

Congenital Koilonychia Newborn

Figure 2.14

Severe congenital koilonychia.

Figure 2.14

Severe congenital koilonychia.

Congenital Toe Abnormalities

Figure 2.15

Koilonychia in hereditary ectodermal dysplasia.

Figure 2.15

Koilonychia in hereditary ectodermal dysplasia.

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