The hard keratin of the nail plate is formed in
the nail matrix, which lies in an invagination of
the epidermis (the nail fold) on the back of the
terminal phalanx of each digit.
The matrix runs from the proximal end of the
ﬂoor of the nail fold to the distal margin of the
From this area the nail plate grows forward over
the nail bed, ending in a free margin at the tip of
The nail bed is capable of producing small
amounts of keratin which contribute to the nail
and which are responsible for the ‘false nail’
formed when the nail matrix is obliterated by
surgery or injury.
The cuticle acts as a seal to protect the potential
space of the nail fold from chemicals and from
The nails provide strength and protection for the
terminal phalanx. Their presence helps with ﬁne
touch and with the handling of small objects.
The rate at which nails grow varies from person
to person: ﬁngernails average between 0.5 and
1.2 mm per week, while toenails grow more
Nails grow faster in the summer, if they are
bitten, and in youth.
They change with ageing from the thin,
occasionally spooned nails of early childhood to
the duller, paler and more opaque nails of the
A. Trauma:A. Trauma:
*Permanent ridges or splits in the nail plate can follow*Permanent ridges or splits in the nail plate can follow
damage to the nail matrix.damage to the nail matrix.
*Splinter haemorrhages, the linear nature of which is*Splinter haemorrhages, the linear nature of which is
determined by longitudinal ridges and grooves in thedetermined by longitudinal ridges and grooves in the
nail bed, are caused by:nail bed, are caused by:
-minor trauma-minor trauma
-psoriasis of the nail-psoriasis of the nail
-subacute bacterial endocarditis.-subacute bacterial endocarditis.
*Larger subungual haematomas are usually easy to*Larger subungual haematomas are usually easy to
identify but the trauma that caused them may haveidentify but the trauma that caused them may have
escaped notice and dark areas of altered blood can raiseescaped notice and dark areas of altered blood can raise
worries about the presence of a subungual melanomaworries about the presence of a subungual melanoma..
**Chronic trauma from sport and from ill-ﬁtting shoesChronic trauma from sport and from ill-ﬁtting shoes
contributes to haemorrhage under the nails of the bigcontributes to haemorrhage under the nails of the big
toes, to the gross thickening of toenails known astoes, to the gross thickening of toenails known as
onychogryphosisonychogryphosis and to ingrowing nails.and to ingrowing nails.
*Onycholysis*Onycholysis, a separation of the nail plate from the, a separation of the nail plate from the
nail bed may be a result ofnail bed may be a result of
-minor trauma-minor trauma
-nail psoriasis-nail psoriasis
-thyroid disease.-thyroid disease.
Usually no cause for it is found.Usually no cause for it is found.
The space created may be colonized by yeasts, or byThe space created may be colonized by yeasts, or by
bacteria such asbacteria such as Pseudomonas aeruginosaPseudomonas aeruginosa, which turns, which turns
it an ugly green colourit an ugly green colour..
B. Nail in systemic disease:B. Nail in systemic disease:
1. Koilonychia:1. Koilonychia:
a spooning and thinning of the nail plate, indicates irona spooning and thinning of the nail plate, indicates iron
2.Colour changes2.Colour changes::
-the ‘half-and-half’ nail, with a white proximal and red or-the ‘half-and-half’ nail, with a white proximal and red or
brown distal half, is seen in patients with chronic renalbrown distal half, is seen in patients with chronic renal
-Whitening of the nail plates may be related to hypo--Whitening of the nail plates may be related to hypo-
albuminaemia, as in cirrhosis of the liver.albuminaemia, as in cirrhosis of the liver.
-Some drugs, notably antimalarials, antibiotics and-Some drugs, notably antimalarials, antibiotics and
phenothiazines, can discolor the nailsphenothiazines, can discolor the nails..
transverse grooves which appear synchronously on all nails a
few weeks after an acute illness.
4.Connective tissue disorders:
nail fold telangiectasia orerythema is a useful physical sign in
dermatomyositis,systemic sclerosis and systemic lupus
In dermatomyositis the cuticles become shaggy.
In systemic sclerosis loss of ﬁnger pulp leads to overcurvature
of the nail plates.
C. Nail changes in the common dermatoses:
The best-known nail change are:
Pitting of the surface of the nail plate
There is no effective treatment for psoriasis of the nails.
Some patients with itchy chronic eczema bring their
nails to a high state of polish by scratching.
In addition, eczema of the nail folds may lead to a coarse
irregularity with transverse ridging of the adjacent
Some 10% of patients with lichen planus have nail changes.
Most often this is a reversible thinning of the nail plate with
irregular longitudinal grooves and ridges.
More severe involvement may lead to pterygium in which the
cuticle grows forward over the base of the nail and attaches
itself to the nail plate
The more severe the hair loss, the more likely there is
to be nail involvement.
A roughness or ﬁne pitting is seen on the surface of the nail
plates and the lunulae may appear mottled.
The portal of entry for the organisms, usually staphylococci, is
a break in the skin or cuticle as a result of minor trauma.
There will be acute inﬂammation, often with the formation
of pus in the nail fold or under the nail.
Treatment is with ﬂucloxacillin or erythromycin and
appropriate surgical drainage.
A mixture of pathogens (yeasts, Gram-positive cocci and
Gram-negative rods) colonize the space between the nail fold
and nail plate.
Predisposing factors include a poor peripheral circulation, wet
work, working with ﬂour, diabetes, vaginal candidosis and
overvigorous cutting back of the cuticles.
Presentation and course
The nail folds become tender and swollen and small amounts
of pus are discharged at intervals. The cuticule is damaged and
the adjacent nail plate becomes ridged and discolored.
The condition may last for years.
Manicuring of the cuticle should cease.
The hands should be kept as warm and dry.
The damaged nail folds packed several times a day with an
If there is no response, and swabs conﬁrm that candida is
present, a 2-week course of itraconazole should be considered.
Treat gram negative rods and gram positive cocci.
The common dermatophytes that cause tinea pedis
can also invade the nails include;
Trichophyton mentagrophytes var.interdigitale
and Epidermophyton ﬂoccosum
Toe nail infection is common and associated with tinea pedis.
The early changes occur at the free edge of the nail and spread
The nail plate becomes yellow, crumbly and thickened.
Usually only a few nails are infected but occasionally all are.
The ﬁnger nails are involved less often and the changes, in
contrast to those of psoriasis, are usually conﬁned to one hand.
The condition seldom clears spontaneously.
Yeast infections of the nail plate, much more rare than dermatophyte
infections, can look similar.
Coexisting tinea pedis favours dermatophyte infection of the nail.
Microscopic examination of a nail clipping.
Cultures should be carried out in a mycology laboratory.
imidazole preparations (e.g. miconazole and clotrimazole),
allylamines such as terbinaﬁne,
benzoic acid ointment (Whitﬁeld’s ointment),
and tolnaftate. They should be applied twice daily.
Topical nail preparations
Nail lacquer containing amorolﬁne. It should be applied once or twice a
week for 6 months,
Amorolﬁne and tioconazole nail solutions.
They can be used as adjuncts to systemic therapy.
terbinafine, griseofulvin, itraconazole and fluconazole.
Are common and stubborn.
Cryotherapy must be used carefully to avoid damage to
the nail matrix. It is painful but effective.
Arise from the nail folds, usually in late childhood, in patients
with tuberous sclerosis.
Can occur beneath the nail plate.
The small red or bluish lesions are exquisitely painful
if touched and when the temperature changes.
Treatment is surgical.
Protrude painfully under the nail plate.
Usually secondary to trauma to the terminal phalanx.
The bony abnormality can be seen on X-ray and treatment is
Occur on the proximal nail folds, usually of the ﬁngers.
The smooth domed swelling contains a clear jelly-like material
that transilluminates well.
Cryotherapy, injections of triamcinolone and surgical excision
all have their advocates.
should be suspected in any subungual pigmented lesion,
particularly if the pigment spreads to the surrounding skin.
Subungual haematomas may cause confusion but ‘grow out’
with the nail.
The risk of misdiagnosis is highest with an amelanotic
melanoma, which may mimic chronic paronychia or a
F. Some other nail abnormalitie:
Rare and inherited as an autosomal dominant trait.
The nails are grossly thickened, especially peripherally.
Hyperkeratosis may occur on areas of friction on the legs and
Inherited as an autosomal dominant trait.
The thumbnails, and to a lesser extent those of the ﬁngers, are
smaller than normal.
Rudimentary patellae, and renal disease complete the
3.yellow nail syndrome
The nail changes begin in adult life, against a background of
hypoplasia of the lymphatic system.
Peripheral edema is usually present and pleural effusions may
The nails grow very slowly and become thickened and
greenish-yellow; their surface is smooth but they are
overcurved from side to side.
4.The nail ‘en racquette’
is a short broad nail usually a thumbnail, which is seen in
some 1–2% of the population and inherited as an autosomal
The basic abnormality is shortness of the underlying terminal