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Image from Nguyen VH. Case Rep Med. 2011;2011:126209. [Open access.] PMID: 22013451 PMCID: PMC3195534.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

From possible malignancy to nutritional status, a significant amount of information pertaining to a patient's overall health can be obtained by examining the fingernails and/or toenails.[1]

Although abnormalities of the nail are often caused by skin disease and infection, they may also indicate more general medical conditions. Careful examination can help the clinician to detect a number of general and specific pathologic indicators.

The above image shows fingernail clubbing. Which of the following conditions can be associated with this?

  1. Glomerulonephritis
  2. Triangular lunula
  3. Hypoplastic patellae
  4. Hamman-Rich syndrome (acute interstitial pneumonitis)
  5. Anhidrotic epidermal dysplasia
Adapted image from Wikimedia Commons | Jfdwolff (retouched by Laogooli).

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Answer: D. Hamman-Rich syndrome (acute interstitial pneumonitis)

Nail clubbing has been associated with various underlying pulmonary and cardiovascular disorders, as well as with neoplastic, infectious, hepatobiliary, mediastinal, endocrine, and gastrointestinal diseases.[2,3 ] Nail clubbing occurs when the angle made by the proximal nail fold and the nail plate, termed the Lovibond angle, is greater than 180° (the Lovibond angle of normal nails is generally <165°) (shown).[4] Hamman-Rich syndrome, or acute interstitial pneumonitis, is a form of idiopathic interstitial pneumonia that is characterized by inflammation of the lung interstitium.[5] With advanced interstitial lung diseases, digital clubbing and signs of right heart failure may appear.[6]

Image courtesy of Andrew Kelsey, MD.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Fungal infections of the fingernails and toenails (onychomycosis) (shown) can be difficult to treat, and recurrences are common. In general, oral terbinafine and itraconazole are first-line agents for managing onychomycosis because of their deep-penetrating effects on the nail matrix and nail bed.[7,8]

Image from Gahalaut P, Mishra N, Chauhan S, Ali MM, Rastogi MK, Thakur R. ISRN Dermatol. 2014;2014:271230. [Open access.] PMID: 24701356, PMCID: PMC3950909.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

The nails shown are lacking a lunula.

Abnormalities of the lunula are common and may lead clinicians down varied diagnostic paths. Absence of the lunula (anolunula) of the thumb should prompt investigation for anemia or malnutrition.[1,9] However, this may also be a normal finding. Anolunula of other digits is nonspecific.

A pyramidal lunula may be a sign of excessive manicure or trauma.[1] A pale blue lunula may indicate diabetes mellitus, whereas a red discoloration of the lunula may signify cardiovascular disease, collagen vascular disease, hematologic malignancy, or another serious diagnosis.[1]

Left images from OpenStax | Herbert L Fred, MD, Hendrik A van Dijk; right image courtesy of Medscape.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Yellow nail syndrome (middle images) is characterized by yellow nails that lack a cuticle, grow slowly, and are loose or detached (onycholysis).[10,11] This condition is most commonly associated with lung disorders (bronchiectasis) and with lymphedema (left images),[10,11] but yellow nails can also be suggestive of diabetes mellitus, amyloidosis, median/ulnar nerve injury, thermal injury, or jaundice.[11]

Which of the following statements about the nail shape shown in the right image is correct?

  1. It is not common in childhood.
  2. It can be associated with iron deficiency anemia.
  3. It can be associated with ingrown nails.
  4. It is associated with psoriasis.
  5. It is due to a nail tumor with psoriasis.
Image courtesy of Medscape.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

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

Koilonychia (shown) is characterized by spoon-shaped, concave nails. Causes of koilonychia include iron deficiency, diabetes mellitus, protein deficiency, systemic lupus erythematosus (SLE), exposure to petroleum-based solvents, trauma, and Raynaud disease.[1,4,11]

Image from Wikimedia Commons | Nickyay.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

The term Lindsay half-and-half nails refers to a condition (shown) in which the proximal portion (40-80%) of the nail bed is white and the distal portion is dark (red, pink, or brown).[12] The whiteness is related to edema and anemia.[4] Lindsay half-and-half nails are indicative of renal disease.[4,12]

Image from Wikimedia Commons | Hojasmuertas.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

In the condition known as Terry nails (shown), the proximal 80% of the nail bed is white, and the distal portion of the bed is a normal pink. Terry nails are caused by a reduced vascular supply to the nail bed.[13] They are indicative of hepatic disease, although they can also suggest diabetes mellitus, congestive heart failure, or hyperthyroidism; in addition, Terry nails can be related to aging.[13,14]

Image courtesy of Medscape.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Longitudinal brown lines (arrows) form as a result of increased melanin production by nail matrix melanocytes.[1] These lines are associated with Addison disease, a melanocytic nevus of the nail matrix, melanoma (check for periungual pigmentation), solar lentigo, certain medications, genetic predisposition, and trauma.[1,11]

Image courtesy of Medscape.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Beau lines (arrow) are transverse depressions in the nail plate resulting from temporary cessation of nail growth.[4,15] Causes include intermittent doses of immunosuppressive therapy or chemotherapy, nail injury, cold temperatures, and illness.[15] Severe zinc deficiency has also been proposed as a cause of Beau lines.[16]

Image courtesy of Dr Kenneth Greer.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Onychorrhexis, or the presence of longitudinal striations or ridges (arrow) on the nail plate, can simply be a sign of advanced age, but it may also be associated with conditions such as rheumatoid arthritis, peripheral vascular disease, lichen planus, and Darier disease (which includes broad white and red striations in the nails).[17]

Image from Wikimedia Commons | Splarka.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Splinter hemorrhages (shown) are caused by small areas of bleeding from the distal capillary loops in the nail bed and are most commonly associated with subacute bacterial endocarditis (classic finding) and local trauma.[4,18,19] These red or brown linear hemorrhages may also be associated with vasculitis,[18] microemboli,[18] trichinosis,[19] onychomycosis,[19] psoriasis,[19] SLE,[11] pityriasis rubra pilaris,[11] or renal failure.[11]

Image from Wikimedia Commons | Yannick Trottier.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Any acute illness can produce transverse white lines, also known as Mees lines.[11] In addition, they may be caused by heavy metal toxicity (classically associated with arsenic poisoning), chemotherapy, carbon monoxide poisoning, Hodgkin disease, malaria, or leprosy.[20] The timing of the causative event or disease process may be determined from the location of the lines on the nails.[11,21]

Image courtesy of Dr Kenneth Greer.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Small punctate depressions of the nails, or "pitting" (shown), is caused by proximal nail matrix inflammation.[17] This inflammation is most commonly related to psoriasis (random appearance of pits), but it is also associated with alopecia areata (geometric, rippled grid), eczema, reactive arthritis, and lichen planus.[15] Nail pitting may also occur without disease.

Images from DeMartinis NC, Cohen PR. Cureus. 2016;8(12):e922. [Open access.] PMID: 28090415, PMCID: PMC5222632.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

The images show green discoloration of the right great toenail due to Pseudomonas aeruginosa infection. Note the green subungual pigmentation involving the nail and proximal nail fold on the superior view (left image) and on the underside of the nail plate on the frontal view (top right) (distal onycholysis allows easy visualization of the underside). The bottom right image shows the underside of the removed great toenail.

Image courtesy of Douglas A Albreski, DPM.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

An extremely rare condition, nail unit melanoma (shown) is responsible for about 1% of all melanomas in the White population. In contrast, it is the most common type of melanoma found in patients with darkly pigmented skin. These cancers are often initially missed or diagnosed incorrectly, leading to a poorer prognosis. The patient presented here was at first treated with topical antifungals and then 3 months of terbinafine, for presumed onychomycosis, prior to a diagnosis of melanoma.[22,23]

Image courtesy of Douglas A Albreski, DPM.

Fingernail and Toenail Abnormalities: Nail the Diagnosis

Mark P Brady, PA-C | March 17, 2021 | Contributor Information

Tuberous sclerosis complex (shown) is a genetic disorder that causes benign tumors to grow in many different organs.[24,25] Ungual or periungual fibromas may appear in adolescents or adults with the condition. Fibromas may cause distortion of the nail or nail bed and can occur as an isolated sign of tuberous sclerosis. When these fibromas involve the toes, they may bleed and cause discomfort.

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