Nails not only have their own problems but also may be affected in many systemic diseases. They provides some guide to the likely cause. If the abnormality is widespread and symmetrical, it is more likely to have an endogenous than an exogenous explanation.
Nails Changes Associated with Systemic Disorders
Abnormally thinned, depressed in center with raised edges giving an appearance of Spoon, so called spoon -shaped nails. It is seen in association with iron deficiency Anemia, Hypothyroidism, 50% of patients with idiopathic Hemochromatosis or following trauma, such as in garage mechanics who regularly fit tires. In Anaemia nails revert to normal if anemia is corrected. It can be congenital (from birth).
Beau’s lines are transverse linear depression in nail plates that occur simultaneously in all nails. They typically follow a systemic illness, zinc deficiency, malnutrition, uncontrolled diabetes mellitus, peripheral vascular diseases, syphilis, due to some drugs or trauma because of temporary arrest of growth of nails. They subsequently migrate out as the nail grow. As with the Mees’lines timing of illness may be estimated by measuring the distance from the line to proximal nail fold. (Nail grow approximately 1mm every 6-10 days)
Finger clubbing or Hippocratic nails (Over Curvature of nails) is a distinct feature associated with number of diseases. In early stages the normal angle between nail plate and proximal nail fold is lost followed by drumsticks appearance of fingernails and toes. The angle between nail plate and proximal nail fold can increase more than 180 degrees. The process usually takes years. Can be familial or idiopathic or show disorder of pulmonary, cardiovascular system and gastrointestinal system such as bronchial carcinoma, Asbestosis (especially with mesothelioma), suppuration or fibrotic lung diseases, cyanotic heart diseases , infective endocarditis, inflammatory bowl diseases, biliary cirrhosis and thyrotoxicosis. Vascular endothelial growth factor play a central role in development of clubbing. It is a platelet derive factor induced by hypoxia and is produced by diverse malignancies.
Brown black pigmentation of the nails is termed melanonychia. It may be partial or total, transverse or linear and may effect one or multiple nails. Brown nail bands are found normally in 90% of black people. Melanonychia is due to melanin, as in nevi, lentigos and melanoma. Although there are many benign causes of longitudinal melanonychia, the most important cause is Subungual Melanoma. Benign melanonychia can be cause by a drugs (such as zidovudine) or by vitamin B12 deficiency and Laugier-Huntziger syndrome in which there are pigmented bands in nails and pigmented macules on lips and oral mucosa.
Mees’ lines (also known as Aldrich or Reynolds’ lines) are transverse white bands 1-2 mm thick on the nail plate laid down during periods of stress. Usually one band per nail. Common associations are poisoning (Arsenic, Thallium, Fluorosis, carbon monoxide poisoning), severe infection, renal disease, cardiac failure, and malignant disease and due to some chemotherapeutic agent. It is noted to occur at the same level in one or several nails. They move distally as the nail grows out.
Muehrcke’s lines are a strong indicator of hypoalbuminemia. These are stationary paired transverse bands which can result from a variety of different causes.
The lines are actually in the vascular bed underneath the nail plate. They do not move with nail growth, and disappear when pressure is applied to the nail. This distinguishes them from “true leukonychia striata” . As in Terry’s and half-and-half nails, the pattern is thought to be formed by bands of localized edema exerting pressure on the surrounding capillaries.
Small longitudinal thin dark red brown lines in nails that resemble a splinters under the nail plate. Usually caused by trauma but can be related to systemic illnesses or drugs. Psoriasis and other medical and vascular events have been associated with splinter hemorrhages. If the lesion occur distally on a single nail, it is less likely to be related to a systemic cause.
Yellow Nails Syndrome
Diffuse yellow, slow growing, thickened nail plates with absent lunula and cuticle. Surface remain smooth or acquires transverse ridges, indicating variation in growth rate.partial or total separation of the nail may occur. Most commonly associated with pulmonary problems such as pleural effusion, bronchiectasis or chronic sinus infections.yellowish nail pigmentation has been reported in patient with AIDS. The underlying pathological process is thought to be related to impaired lymphatic drainage. Nail may spontaneously improve, even when the associated disease does not improve.
The proximal nail plate are white or light pink ground-glass looking (greater than 80% of the entire nail plate) with a 0.5-3 mm normal pink or brown distal band. The lunula is obliterated. The findings are associated with cirrhosis, chronic congestive heart failure, chronic renal failure. The condition can also result from normal aging, viral hepatitis, T2 diabetes mellitus and tuberculoid leprosy.
Half and Half Nail
Also called Lindsay’s nails characterized by a proximal white, ground-glass looking nail plate and distal pink, red or brown nail plate, with latter occupying at least 20-60% of the total length of the nail.The condition mainly effect fingernails and less often toenails. Distinguished from Terry’s Nails in which the distal pink, red or brown zone occupies less than 20%. The proximal white band is believed to result from chronic anemia, increase thickness of capillary wall and overgrowth of connective tissue between the nail plate and the underlying structure with reduction of blood flow in subpapillary plexus. The distal pink, red or brown coloration is caused by increased melanin deposition, possibly stimulated by uremic or other toxins or by stagnant venous return. As the two bands do not move with the growth of nail so the nail bed is likely be the cause of primary pathologic site. Lindsay’s nails occur in 8-50% of chronic renal failure patients especially who are on hemodialysis. The condition may also occur in association with Crohn’s disease, Kawasaki’s disease, liver cirrhosis, Bechet disease, yellow nails syndrome, T2 diabetes mellitus, pellagra, Zinc deficiency and medications (such as isoniazid, chemotherapeutic agents). Lindsay’s nail may also be idiopathic and occur in healthy individuals. A longitudinal half and half nail also described. Usually occur on thumbs or toes. Cause may be trauma or idiopathic.
Infections of Nails
Onychomycosis is an infection of the nails caused by dermatophytes, yeast or molds. Dermatophytes are fungi that can easily attack skin, hairs and nails due to their keratinolytic enzymes. Predisposing factors are a familial history, diabetes, immunosuppression, and trauma to the nails. Primary dermatophyte infections occurs in four main patterns, that is distal and lateral subungual onychomycosis, superficial white onychomycosis, proximal subungual onychomycosis, and total dystrophic onychomycosis. The nail plate get Brown, yellow, orange or white discoloration, thickened due to subungual hyperkeratosis and onycholysis is common.
Pseudomonas Nail Infection
Green or black discoloration of under surface of nail plates. Onycholysis is usually present and Paronychia is common. There is little discomfort or inflammation in pseudomonas infection of a nail. A few drops of a mixture of one part chlorine bleach and four part water under the nail three times a day cures the condition. Vinegar can be used also.
The rapid onset of painful, bright red swelling of the proximal and lateral nail fold may occur spontaneously or may follow a trauma or manipulation.
Inflammation of proximal and lateral nail folds that may be colonized by candida. Nail folds are often red swollen and tender. Significant contact irritant exposure is a major cause. People whose hands are repeatedly get wet (baker, dishwasher, housemaids) are at increased risk. Typically many or all fingers involved simultaneously. The cuticle separate from the nail plate leaving the space between proximal nail fold and nail plate exposed to infections. The process is chronic and respond slowly to treatment.
Nail Disorders Associated with Skin Conditions
Nail involvement usually occur simultaneously with psoriatic skin disease but it may occur as an isolated finding. More than 50% of patients suffer from pain, and many are restricted in their daily activities. Small punched-out depression seen as pitting on nail plate. Nail plate cells are shed in same way as psoriatic scales. Many other cutaneous diseases also cause pitting like, Eczema, chemical dermatitis, Reiter’s syndrome, Sarcoidosis, Alopecia Areata, fungal infections or it may occurs as an isolated finding in normal variation. Psoriasis of nail bed may cause localized separation (onycholysis) of the nail plate. Nail detach in an irregular manner. Nail plate turn yellow simulating a fungal infection. Cellular debris and serum may collect in the space. The brownish yellow color observed through the nail plate looks like a spot of oil. Psoriasis of entire nail matrix may cause grossly deformed nails.
Approximately 25% of patients with nails lichen planus (LP) have LP in other sites before or after the onset of nail lesions. Metal allergy have been implicated. The matrix, nail bed and nail folds may be involved in producing a variety of changes. Inflammation of matrix cause ridging and grooving of nail plate. A pterygium, caused by adhesion of a depressed proximal nail fold to the scarred matrix may occur after intense matrix inflammation. Onychomycosis may be confused with lichen planus.
The separation usually start distally but can start proximally. The detached nail plate appear white due to air between nail plate and nail bed. Patients may have a history of using irritants (e.g. Nails cosmetics, soaps and detergent), ill- fitting shoes, long nails, trauma. Onycholysis may also be associated with psoriasis, fungal infection, yellow nail syndrome, contact dermatitis, medications (such as doxycycline), and thyroid disease as well as many environmental causes. Separated nail should be clipped off and kept dry.
When an injury to a nail occur, a hemorrhage (blue or black ) often form under the nail plate. It usually grows out with the nail. Any persistent hemorrhage needs to be distinguished from subungual melanocytic lesions especially melanoma.
White spots in the nail plate (Leukonychia Punctata) is a very common finding, possibly result from cuticle manipulation or other mild form of trauma. The spots or bands may appear at the lunula or may appear spontaneously on the nail plate and subsequently disappear or grow with the nail.
Distal plate splitting or peeling resembling scaling of dry skin. Repeated water immersion and frequent use of nail polish remover dehydrate the nails. A moisturizer may be applied and then cover with gloves or soaks.
Triangular strips of skin may separate from the lateral folds, perticularly during the winter months. Attempt at removal cause pain. Separated skin should be cut. Constant lubrication of the fingertips with skin creams (e.g. Aquaphor ointment) and avoidance of repeated hand immersion in water is helpful.
Ingrown toenail or fingernails are common. The large toe is frequently affected. The nail pierce the lateral nail fold and enter the dermis where it acts as a foreign body. The penetration cause inflammation pain and swelling. Ingrown nails is caused by poorly fitting shoes, improper or excessive trimming of nails, or trauma.