The primary purpose of the nail is protection. Abnormalities of the nail, though often caused by skin disease and infection, may also indicate more general medical conditions. Careful examination can help the clinician detect a number of general and specific pathologic indicators. Image courtesy of Wikimedia Commons.

This patient has clubbing, which can be associated with:
A. Glomerulonephritis
B. Triangular lunula
C. Hypoplastic patellae
D. Hamman-Rich syndrome
E. Anhidrotic epidermal dysplasia

Answer: D. Hamman-Rich syndrome

Nail clubbing has been associated with various underlying pulmonary and cardiovascular diseases (80%), as well as neoplastic, infectious, hepatobiliary, mediastinal, endocrine, and gastrointestinal diseases. Nail clubbing occurs when the angle made by the proximal nail fold and nail plate is greater than 180 degrees, termed the Lovibond angle (shown). Hamman-Rich syndrome, or acute interstitial pneumonitis, is a form of idiopathic interstitial pneumonia characterized by inflammation of the lung interstitium. With advanced interstitial lung diseases, digital clubbing as shown in this image and signs of right heart failure may appear.

Diseases of the nails can cause significant social, psychological, and physical damage to an affected individual. These disorders may be isolated to the nail unit itself or be part of a larger systemic disease that may present first, or only, in the nail unit. The image shown is of an individual with chronic mucocutaneous candidiasis, a condition characterized by recurrent or persistent superficial infections of the skin, mucous membranes, and nails. Image courtesy of Antonella Tosti, MD.

The best treatment choice for this patient is:
A. Terbinafine
B. Griseofulvin
C. Etanercept
D. Prednisone
E. Itraconazole

Answer: E. Itraconazole

Itraconazole capsules are used to treat fungal nail infections of the fingers and toes (the oral suspension is used for oral candidiasis).^[3] This medication has deep penetrating effects into the nail matrix and nail bed,^[4] whereas most topical fungal agents have insufficient nail penetration.^[5] Itraconazole must be used with precaution in patients with ventricular dysfunction (eg, congestive heart failure [CHF], previous CHF) as it may cause CHF. In addition, itraconazole has numerous adverse drug interactions with medications that use the cytochrome P450 3A4 system, resulting in increased levels of such agents. See the black box warnings in the prescribing information. Courtesy of Walter Reed Army Medical Center.

Examination of the nails should include the softness and flexibility of the free edge, the shape and color of the nail, the quantity of paronychial tissue, and the growth rate. Aging slows the whole fingernail growth rate from about 3 months in children to about 6 months at age 70. Nails of the dominant hand usually grow faster than nails of the nondominant hand. The growth rate can also be slowed by immobility. Nails are usually thicker in the elderly than in younger people. Image courtesy of Wikimedia Commons.

The arrow points to what part of the finger nail?
A. Lunula
B. Eponychium
C. Cuticle
D. Nail groove
E. Proximal nailfold

Answer: A. Lunula

The lunula is most noticeable on the thumb. The eponychium may partially or completely cover the lunula. Absence of the lunula of the thumb should prompt investigation for anemia or malnutrition. It may also be a normal finding. Absence of the lunula of other digits (shown) without the thumb is nonspecific.

Which of the following statement regarding abnormalities of the lunula is true?
A. Absence of the lunula may suggest performing a complete blood count
B. A pyramidal lunula is seen in cases of excessive manicure or trauma
C. A pale blue lunula suggests systemic lupus erythematosus
D. A red discoloration of the lunula has no significance
E. The lunula is part of the nail bed

Answer: A. Absence of the lunula may suggest performing a complete blood count

Abnormalities of the lunula are common and may lead clinicians down varied diagnostic paths. While a pale blue lunula suggests diabetes mellitus, a red discoloration of the lunula may signify cardiovascular disease, collagen vascular disease, hematologic malignancy, or other serious diagnosis.

This patient has:
A. Carotid stenosis 
B. Yellow nail syndrome
C. Nail polish contact dermatitis
D. Heart disease
E. Lichen planus

Answer: B. Yellow nail syndrome

Yellow nails can be suggestive of diabetes mellitus, amyloidosis, median/ulnar nerve injury, thermal injury, and jaundice. Consider yellow nail syndrome if a patient has lymphedema and bronchiectasis.

Which one of the following statement about the nail shape shown is correct?
A. It is not common in childhood
B. It can be associated with iron deficiency anemia
C. It can be associated with ingrown nails
D. It is associated with psoriasis
E. It is due to a nail tumor with psoriasis

Answer: B. It can be associated with iron deficiency anemia

Koilonychia are spoon-shaped, concave nails. Causes of koilonychia include iron deficiency, diabetes mellitus, protein deficiency (especially in sulfur-containing amino acids), exposure to petroleum-based solvents, systemic lupus erythematosus, and Raynaud disease.

Which of the following statements about the nails showing Terry's half and half nails is true?
A. These findings can signify either renal or liver disease 
B. Renal disease is associated with brown nail beds
C. The white portion is related to poor circulation 
D. They are Beau's lines

Answer: A. These findings can signify either renal or liver disease

Terry's half and half nails refers to a condition where the proximal portion of the nail is white and the distal portion is dark. The white portion is related to edema and anemia. These nails imply either renal or liver disease. The presence of a brown band at the junction of the erythema and the free edge of the nail suggests the condition is renal in nature. Image courtesy of Dermnet.

Longitudinal brown lines (arrows) form because of increased melanin produced by nail matrix melanocytes and are associated with Addison disease, nevus at the nail base, breast cancer, melanoma (check for periungual pigmentation), and trauma.

Intermittent doses of immunosuppressive therapy or chemotherapy can also produce Beau's lines (blue arrow). Severe zinc deficiency has also been proposed as a cause of Beau's lines. By noting its location on the nail, the approximate date of the illness associated with it can be determined. Moreover, the depth of the line provides a clue to the severity of the illness.

Finding only 1 or 2 half and half nails in a patient should lead the clinician toward which of the following diagnoses? Image courtesy of Dr. Kenneth Greer.

A. Proximal white subungual onychomycosis fungal infection of the nail
B. Nail bed trauma
C. Renal failure
D. Anemia
E. Nail patella syndrome

Answer: A. Proximal white subungual onychomycosis fungal infection of the nail

The area will progressively migrate distally with nail growth. If caused by a mold, there is typically marked periungual inflammation. In contradistinction, onycholysis (shown) is distal separation of the nail plate from the underlying nail bed and is associated with thyrotoxicosis, psoriasis, trauma, contact dermatitis, tetracycline, eczema, toxic exposures (solvents), blistering from autoimmune disease and porphyria cutanea tarda (onycholysis and skin blistering from sun exposure). Image courtesy of Wikimedia Commons.

The nail shown demonstrates a condition called onychorrhexis. Image courtesy of Dr. Kenneth Greer.

Which of the following is true?
A. It can simply be a sign of advanced age
B. It may occur with nail sculptures
C. It is improved with vitamin therapy
D. It is more common in toenails than fingernails
E. It is not seen in brittle nail syndrome

Answer: A. It can simply be a sign of advanced age

Onychorrhexis, or the presence of longitudinal striations or ridges, can simply be a sign of advanced age but may also occur with rheumatoid arthritis, peripheral vascular disease, lichen planus, and Darier disease (white and red striations). Central riding may be due to myxoid cysts.

                                   

Which of the following statements is true regarding the condition noted in the nail shown? Image courtesy of Wikimedia Commons.
A. It is caused by hemorrhage of the proximal capillary loop
B. It is not associated with systemic lupus erythematosus
C. It can be associated with hepatic failure
D. The clinician should look for additional signs and symptoms of subacute bacterial endocarditis
E. It is due to contact with wood splinters

Answer: D. The clinician should look for additional signs and symptoms of subacute bacterial endocarditis

Splinter hemorrhages are caused by hemorrhage of the distal capillary loop and can be associated with subacute bacterial endocarditis, systemic lupus erythematosus, trichinosis, pityriasis rubra pilaris, psoriasis, and renal failure.

Any acute illness can produce transverse white lines (Mees' lines). In addition, they might be caused by heavy metal toxicity (classically arsenic) or chemotherapy. The time of event may be determined from the location of the lines on nail.

Which of the following statements regarding the nail condition in this slide is false? Image courtesy of Hon Pak, MD.
A. It may be related to systemic lupus erythematosus
B. It is caused by nail matrix inflammation
C. It can be seen in lichen planus
D. It commonly occurs in eczematous conditions
E. It comes from the distal matrix 

Answer: A. It may be related to systemic lupus erythematosus

Small punctate depression of the nail or "pitting" (red arrow) is caused by nail matrix inflammation. This inflammation is most commonly related to psoriasis (random appearance of pits) but can also be found in alopecia areata (geometric rippled grid), eczema, and lichen planus. Nail pitting may also occur without disease. Image courtesy of Dr. Kenneth Greer.

Nail color is a potentially useful method for identifying systemic problems. White nails can be caused by anemia, renal failure, cirrhosis, diabetes mellitus, chemotherapy, or edema. Pink or red nails may be from polycythemia, systemic lupus erythematosus, carbon monoxide poisoning, or malnutrition. Brown-gray nails may be from cardiovascular disease, diabetes mellitus, vitamin B12 deficiency, breast cancer, melanoma, lichen planus, or syphilis. Green or black nails may be from trauma, chronic Pseudomonas infection, or topical chlorophyll preparations.

From possible malignancy to nutritional status, a significant amount of information pertaining to the patient's overall health can be obtained from examination of the fingernails as listed in this slide. To get the most information, clinicians should undertake examination of the nail at each physical and be sure to perform all nail examinations in adequate light.