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NAILS
Prof. Ihab Younis
Anatomy
1-Nail plate: is the hard and translucent portion, composed of keratin. Its free edge is the part that
extends past the finger
2. Lunula : is the crescent shaped whitish area of the nail bed
3. Eponychium or cuticle, is the fold of skin at the proximal end of the nail
4. Nail fold : a fold of hard skin overlapping the base and sides of the nail
5. Nail matrix : situated directly below the cuticle. New cells form here to produce the nail plate. It
also contains blood vessels and nerves. If the matrix is damaged the nail will grow deformed
6. Nail bed : It is continuation of the matrix and the part that the nail plate
rests on
7. Hyponychium: is the attachment between the skin of the finger or toe and the distal end of the
nail
Nail growth and factors affecting it:
•The nail can take between 5 - 6 months to grow from the matrix to the free edge
•In children the growth is rapid 6 – 8 weeks
•In adults nails grow approximately by 1 mm a week
•Nail growth is quicker:
· During pregnancy
· In the summer than in the winter
· On the hands than the feet
•If the matrix is damaged by trauma, the nail will grow back deformed
•Nail growth is inversely proportional to age
•With advancing years the nail plate becomes paler and opaque and white nails similar to those seen in
cirrhosis, uraemia and hypoalbuminaemia may be seen in normal old persons
•Longitudinal ridging is present to some degree in most people after 50 years of age
I-Nail disorders
1.Congenital
Anonychia
•Some or all the fingernails and toenails are absent without significant bone anomalies
•It is a rare condition and may have an autosomal dominant inheritance pattern
Nail patella syndrome
•A rare autosomal dominant syndrome
•There is a tetrad of fingernail dysplasia with triangular lunula, absent or hypoplastic patellae, posterior
iliac horns, deformation of the radial heads
Pachyonychia congenita
•A rare autosomal dominant disease
•There is hypertrophy of the nails
associated in some cases with nail bed and hyponychia
hyperkeratosis
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•May be associated with palmoplanter hyperkeratosis, warty skin lesions on the limbs,
hyperhidrosis
and lustreless and kinky scalp hair
2.Traumatic
Acute trauma
•It is classified with respect to severity, ranging from a small hematoma to digit amputation
Nail biting
•It is found in 60% of children, 45% of adolescents and 10% of adults
•The majority of moderate nail biters have no associated psychiatric disorder
•Patients are susceptible to bacterial and viral infections producing whitlows. It may also result in the
transportation of bacteria that are buried under the surface of the nail, or pinworms from anus region to
mouth
•Regarding social effects the aesthetic aspect of the nail may affect employability, self-esteem, and
interaction with other people
•The nails are typically short, with up to 50% of thenail bed exposed.The free edge may be even or
ragged. Surface change may include splitting of the nail into layers or a sand-papered effect, and the
nail may acquire a brown longitudinal streak
•Cure relies largely on the motivation of the patient
• Local antiseptics and antimicrobial ointments may help settle the infection secondary to nail-unit
damage
•Antidepressants and behavioural therapy have been used with some success in limited studies
Hangnail
•Trim the skin of the hangnail with a pair of clean scissors .
•These are due to hard pieces of epidermis breaking away from the lateral nail folds
•Although often due to nail biting, they may result from many other minor injuries
•The splits may be painful when they penetrate to the underlying dermis
•They should be removed with sharp, pointed scissors
Trauma by footwear
•Due to repetitive trauma by footwear, the great toenail becomes thickened, yellow and twisted
(onychogryphosis). It is most commonly seen in the elderly
•Treatment is either :
- Radical by surgical removal of the nail and matrix and is recommended in young persons with
good circulation
- Palliative treatment requires regular paring and trimming of the affected nails, usually by a
chiropodist
Ingrowing toenail
•The lateral nail fold of the great toe is penetrated by the edge of the nail plate, resulting in pain, sepsis
and, later, the formation of granulation tissue
•The main cause for the deformity is compression of the toe from the side due to ill-fitting footwear
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•In infancy, ingrowing toenail most commonly occurs before shoes are worn, associated with crawling,
or wearing undersized jumpsuits
•Treatment is by:
-Avoiding tight-fitting or high-heeled shoes
- oral antibiotics or topical antibiotic ointments combined with local anaesthetic agents help to heal
the toe faster and also provide pain relief
- Surgical removal of the ingrown toenail may be required if the condition worsens
3-Infections
Paronychia
•It is a soft tissue infection around a fingernail
•It results from a breakdown of the protective barrier between the nail and the nail fold leading to entry
of bacteria or fungi into the area
•It is the most common hand infection
Etiology
Acute paronychia
•Usually results from a minor(e.g. nail biting) trauma that breaks down the physical barrier between the
nail bed and the nail allowing the infiltration of infectious organisms
•S. aureus is the most common infecting organism. Organisms, such as Streptococcus and
Pseudomonas species, gram-negative bacteria, and anaerobic bacteria are other causative organisms
Chronic paronychia
•It is primarily caused by a mixture of C.albicans and bacteria
•It can also be a complication of eczema
•Most often it occurs in persons whose hands are repeatedly exposed to moist environments or in those
who have prolonged and repeated contact with irritants such as mild acids, mild alkalis, or other
chemicals. People who are most susceptible include housekeepers, dishwashers, and swimmers
Clinically
Acute paronychia
•The presenting complaints are pain, tenderness, and swelling in one of the lateralfolds of the nail
•The affected area often appears erythematous and swollen
•In more advanced cases, pus may collect under the skin of the lateral fold
•If untreated, the infection can extend into the eponychium, both lateral folds and in severe cases, the
infection may track proximally under the skin of the finger and volarly to produce a felon (whitlow)
which is an abscess involving the bulbous distal end of a finger
Chronic paronychia
•Patients complain of symptoms lasting 6 weeks or longer
•The nail folds become swollen, erythematous, and tender without fluctuance
•Eventually, the nail plates become thickened and discolored, with pronounced transverse ridges
•The cuticles and nail folds may separate from the nail plate, forming a space for the invasion of
various microorganisms
Treatment
Acute paronychia
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•Oral antibiotics with gram-positive coverage against S aureus, such as amoxicillin and clavulanic acid
(Augmentin) or clindamycin (Dalacine C), are usually administered concomitantly with warm water
soaks 3-4 times/day
•Dalacine C and Augmentin also have anaerobic activity; therefore, they are useful in treating patients
with paronychia due to oral anaerobes contracted through nail biting
•If the paronychia does not resolve or if it progresses to an abscess, it should be drained promptly
Chronic paronychia
•The avoidance of moist environments or skin irritants is essential for recovery
•Because of the 'mixed' etiology of the inflammation, many clinicians use antibiotic-anticandidasteroid creams combinations. Oral ketoconazole or fluconazole may be added in more severe cases
•Patients with diabetes and those who are immunocompromised need more aggressive treatment
because the response to therapy is slower in these patients than in others
•Cryosurgery, using liquid nitrogen spray to the nail folds, or surgical removal of the proximal nail fold
and adjacent part of the lateral nail folds, may cure recalcitrant cases
Pseudomonas infection
•It is always a complication of onycholysis or chronic paronychia
•The nail plate has a characteristic bluish-black or green color due to accumulation of the pigment
pyocyanin below the nail which may remain after the organism has been removed
•Treatment is as described for paronychia
•Gentamicin or sulphacetamide eye drops can be used to eradicate the colonization in resistant cases
4-Tumors
•Warts
•Fibrokeratoma:They arise in the periunguium and have a hyperkeratotic tip and narrow base
•Subungual exostosis: It is a benign bony outgrowth of the distal part of the toe
Glomus tumour: There is pain, which may be spontaneous or evoked by mild trauma or temperature
change. Nail-plate changes depend on the location of the tumour. Matrix tumours cause splitting and
distortion of the nail plate. Nail bed lesions are most likely to appear as bluish or red foci of 1-5mm
diameter beneath the nail
•Squamous cell carcinoma: There are hype-rkeratotic, warty changes, erosions and fissuring,
macerated cuticle, periungual swelling, erythema
•Melanocytic nevi: Present as longitudinal melanonychia
•Malignant melanoma:There are many features that should suggest the possibility of malignant
melanoma:
-The presence of brown-black periungual pigmentation
-The pigmentation develops in a single digit in adult life
-The pigmentation is evolving to become darker and broader and has blurred edges
-Longitudinal melanonychia(75% of cases)
II-Dermatoses affecting the nails
1-Psoriasis
Psoriasis is the most common disorder affecting fingernails(50% of psoriatics) It manifests as:
•Pitting:Punctate surface depressions
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•Onycholysis:Separation of the nail from the nail bed either proximally or distally
•Subungual hyperkeratosis:Most marked distally and extends proximally
•Splinter hemorrhage:may be due to the increased capillary prominence and in nail-bed dermis
2-Darier's disease
•There are white and red longitudinal lines and distal notching
3-Lichen planus
•Nail involvement occurs in 10% of individuals with disseminated LP
• Nail apparatus involvement may be the only manifestation
• One, several, or all 20 nails may be involved ("twenty-nail syndrome," where there is loss of all 20
nails without any other evidence of lichen planus elsewhere on the body)
•There is thinning of the nail plate and longitudinal ridging
•Typically, the area of thelunula is more elevated than the more distal portion
4-Alopecia areata
•The nail plate is rough with a "hammered brass" appearance
5-Eczema
•Severe pompholyx around the nail folds may cause nail dystrophy, resulting in irregular ridges
III-Nail signs in systemic disease
A-Abnormalities of shape
1-Clubbing
•It is the bulbous uniform swelling of the soft tissue of the terminal phalanx of a digit with subsequent
loss of the normal angle between the nail and the nail bed
•It is due to vasodilation of the digit blood vessels, the cause of which is unknown
Causes :
1-Primary (idiopathic)clubbing e.g. familial clubbing
2-Secondary clubbing include the following:
•Pulmonary disease e.g. Lung cancer, cystic fibrosis
•Cardiac disease e.g. Cyanotic congenital heart disease
•GIT disease e.g. inflammatory bowel disease
•Skin disease e.g. Pachydermoperiostosis
•Malignancies e.g. Thyroid cancer, Hodgkin disease, leukemia
•Miscellaneous conditions e.g. Acromegaly, pregnancy, and hypoxemia possibly related to long-term
smoking of cannabis
2-Koilonychia
•Nails become concave (spoon-shaped)
•It is common in infancy as a benign feature of the great toenail
•The most common systemic association is with iron deficiency
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3-Beau's lines
•They are deep grooved lines that run from side to side on the fingernail due to a temporary cessation
of cell division in the nail matrix
•This may be caused by an infection or trauma in the nail matrix
•Systemic reasons include: coronary occlusion, hypocalcaemia, diabetes, certain drugs - including beta
blockers
4-Muehrcke's lines:
•They are superficial (not grooved as beau’s line) white lines that extend all the way across the nail and
lie parallel to the lunula
•The lines are actually in the vascular nail bed underneath the nail plate, and so they do not move with
nail growth and disappear when pressure is placed over the nail
•The appearance of Meuhrcke's lines is nonspecific, but they are often associated with decreased
protein synthesis, which may occur during periods of metabolic stress (e.g., after chemotherapy) and in
hypoalbuminemic states such as the nephrotic syndrome
5-'True' Leukonychia
•It is the most common form of leukonychia, small white spots affecting one or two nails
•Picking and biting of the nails are a prominent cause in young children and nail biters
•In most cases, they disappear after around eight months, which is the amount of time necessary for
nails to regrow completely
III-Changes in nail color
Terry’s nails
•The nails are white proximally and normal distally
•It occurs in cirrhosis, congestive heart failure and adult-onset diabetes
Yellow nail syndrome
•The nails are yellow due to thickening, sometimes with a tinge of green
•The lunula is obscured and there is increased transverse and longitudinal curvature and loss of cuticle
•It is usually accompanied by lymphoedema and pleural effusions
Color changes due to drugs
•Chloroquine may produce blue-black pigmentation of the nail
•Arsenic may produce longitudinal bands of pigment or transverse white stripes (Mees' stripes) across
the nail
Nail cosmetics
•Professional taking care of the fingernails is known as a manicure
•Professional taking care of the toenails is known as a pedicure
Nail polish
•In 1930, Charles Revson developed the first pigmented, opaque nail polish, which launched Revlon
•Nail polish basically consists of:
1-Cellulose film formers, such as nitrocellulose. These give gloss, body and gel structure
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2-Resins, such as toluene sulphonamide formaldehyde resin, to improve the gloss and adhesion of the
film
Plasticizers, such as dibutylphthalate, added to give the film pliability, to minimize shrinkage, and
soften and plasticize the cellulose
4-Suspending agents, such as bentonite, for non-settling and flow. They keep pigments in suspension
on shaking
5-Solvents (such as butyl) and diluents (such as toluene), which keep other ingredients in a liquid state
and control the application and drying time
6-Color substances. These are either inorganic (iron oxides) or a variety of certified organic colors (D
and C yellow, A1 lakes). In principle, they require to be insoluble in a nail lacquer system
Problems of nail polish
1-Contact dermatitis:
•Frequently appears on any part of the body accessible to the nails, with no signs in or around the nail.
The commonest areas involved are the eyelids, the lower half of the face,the sides of the neck and the
upper chest
•Formaldehyde resin is the most common cause
2-Nail plate discoloration:
•Nail-plate staining from the use of polish is most commonly yellow-orange in color
3-Nail polish removers:
•These are composed of various solvents such as acetone which occasionally cause trouble by
excessive drying of the nail plate and may be responsible for some inflammation of nail folds
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