Nailing Your Diagnosis: The Hand Exam

Is there a structured way to approach nail conditions?

The easiest way to approach the differentials is by splitting them into two categories: localized nail conditions and systemic, which can be a harbinger for another underlying condition. Next, when dealing with localized conditions, understanding the anatomy of the nail bed can further help distinguish conditions. Another way to look at these conditions is by determining what part of the matrix is involved.

How to approach the history and exam

Knowing the anatomy above is crucial. Furthermore, patients should be instructed, ideally by your staff prior to their visit (if in the outpatient setting), to remove any nail polish present. If you would like to document changes over time, utilize your local hospital or clinic policy for taking photographs to include in the clinical record. Understand that regardless of sex, race, or ethnicity, the nail bed color is identical. Therefore, any preserved discoloration may be pathological or physiologic and should not be attributed to normal variants. (Jefferson J).

The following social and familial historical elements are helpful in creating a differential diagnosis:

• Occupation
• Exposures to topical substances
• Medication history
• Smoking or tar use
• Illicit drug history
• Family history of similar findings/concerns

When it comes to the specific complaint, it is important to know the following information:

• How many digits are affected and whether the condition spread or affected all digits at once
• History of trauma to the affected digits
• Any recent stress
• Whether or not all the nails appear similar

Are all abnormal appearances to the nail suggestive of disease? (Mayeaux)

No; There are normal nail variants that every clinician should be aware of (see table below for those that may be associated with underlying systemic disease). Many times, these variants are associated with a disruption in nail formation. Many patients think that abnormalities in the nails, even if they are normal variants, are suggestive of an underlying vitamin deficiency. It is important to reassure these patients as to which findings are concerning based on your exam and which are not.

• Transverse striate leukonychia – Also known as transverse white streaks, these can be seen in a healthy patient and are not suggestive of underlying pathology. The best way to distinguish these is by looking at the lateral most portion of the nail, as these streaks will not extend to the lateral most portion of the fold.
• Nail hypertrophy – Development of opaque thickened nails, also called ram’s horn nail, that can occur with age, fungal infections, and trauma. Typically asymptomatic; however, pain may occur if pressure is placed directly onto the nail.
• Habit-tic deformity – Habitual picking of the proximal nail fold can result in secondary inflammation and damage to the nail plate, leading to a ridged appearance.
• Beau lines – Discussed extensively above and below, can occur with trauma or severe illness when of pathologic origin.
• Lindsay nails – Also known as half-and-half nail, the proximal portion of the nail is white and the distal portion is pink, with a sharp demarcating line between the two halves. Can be seen also in patients with cirrhosis and HIV.

Is this a vitamin problem? (Seshadri D, 2012)

The nail itself requires myriad nutrients to stay healthy. Most vitamin deficiencies are due to either inadequate dietary intake or malabsorption. Vitamin D, which can be obtained through sun exposure, is one of the few exceptions. Lack of these nutrients may affect the nail, the nail bed, or both and may present on physical exam or with biopsy. Common conditions we experience in the primary care setting, such as iron deficiency and magnesium deficiencies in patients with alcohol use disorder, can affect their concentrations, or lack thereof, in the nail. Below, we will discuss common nail findings associated with malnutrition and vitamin/mineral deficiencies.

Nutrition deficiencies

• Beau lines – Associated with protein deficiencies in patients with chronic alcohol use disorder. Present as transverse depressions in a linear fashion of the nail due to disruption in the growth of the nail.
• Terry nails – Seen in those with cirrhosis and malnutrition. When looking at the proximal nail bed, it will appear as a pink or brown band.
• Muehrcke lines (Pfeiffer C, 1974) – Patients with chronically low albumin and/or zinc levels may develop this exam finding; correction of albumin levels (< 2.2 g/mL) will lead to resolution of the findings. Look for narrow, white transverse linear bands that disappear if you press down on the distal portion of the nail.
• Brittle nail syndrome – Those who are chronically malnourished can develop brittle nail syndrome, which presents with soft, weak, and easily breakable nails that form longitudinal splits. In your younger patients who present with this, ask about disordered eating habits that may reveal underlying anorexia. In your elderly patients, this may be a sign of dementia.

Vitamin and mineral deficiencies

• Iron deficiency (Ghaffari S, 2018) (Adhikari, 2018) – Commonly seen in the primary care setting, iron deficiency can cause koilonychias, presenting as a reverse curvature of the nail bed due to the effects that a lack of iron has on the distal matrix. This isolated effect on the distal,  rather than proximal, matrix causes the nail to grow in a downward direction. In post-gastrectomy patients who are at risk for malabsorption, remember that koilonychias may be a sign of deficiencies if routine testing (CBC with mean corpuscular volume [MCV] level) are not abnormal.
• Selenium deficiency (Hasunuma N, 2014) (Tonelli M, 2015) – Found in poultry, milk, wheat, and potatoes, selenium is mostly obtained through plants due to its presence in the soil. Deficiency can be seen in vegetarians who consume food where the soil is deficient in selenium. In first world countries, can be observed in those on both hemodialysis and peritoneal dialysis or inflammatory bowel disease. On exam, look for opaque, whitened nail beds.
• Calcium deficiency (al., 2015) – Transverse white bands along multiple nails in the relatively same position can occur with calcium deficiencies, but they are reversible with treatment. Measuring the distance from the nail fold can help estimate the duration of symptoms (the growth rate is 1 mm/month in the toes and 3 mm/month in the fingers). Ultimate cause is unclear but may be associated with arterial spasm and ischemia.
• Vitamin C deficiency (DiBaise M, 2019) (PJ, 2011) (Rollier R, 1955) (NIH, 2018) – First diagnosed by James Lind in sailors who were at sea for long periods of time in the 1700s, scurvy is associated with a deficiency in vitamin C, either due to diet (rare) or more commonly malabsorption, second-hand smoke exposure, and alcohol use disorder. Due to the importance of vitamin C for collagen production, the deficiency manifests as brittle nails, koilonychias, and splinter hemorrhages. Other than nail findings, classically patients will have gingival inflammation with corkscrew hairs and loose teeth.
• Zinc deficiency (Pfeiffer C, 1974) (Morgan Z, 2011) – Can appear as white, opaque spots on the nail, more commonly in the index or fifth digits of the dominant hand. As mentioned above, these are also called Muehrcke lines, as they may be associated with low albumin levels.
• Fat-soluble vitamin deficiency (al. S. M., 2011) – Deficiencies specifically in vitamins A, D, E, and K typically will cause nails to be softer, termed hapalonychia. Yellow discoloration of the nails, not to be confused with onychomycosis, can occur with vitamin E deficiencies. Warn patients that those fat-soluble vitamins can be toxic if taken in larger than recommended amounts, as these vitamins are stored in the liver and adipose tissue.
• Water-soluble vitamin deficiency (Yiping M, 2014) (Cakmak SK, 2006) (Staggs CG, 2004) (Supplements., 2018) – The majority of water-soluble vitamins that, when deficient, present with abnormal nail findings, center around the B complex of vitamins. Koilonychia, as presented above, can occur with Vitamin B2 and B3 deficiency in particular. While these can be due to nutrient deficiencies from a diet lacking in dairy (think lactose intolerance), they can also occur from medications affecting their absorption (ie, nicotinamide or isoniazid therapy). Other than koilonychia, look for dermatologic manifestations of cheilitis, aphthous ulcers, and pharyngitis.
• Vitamin B3 deficiency, also known as pellagra, occurs with poor intake of poultry, nuts, seeds, legumes, and beef. Low levels can lead to a unique finding of half-and-half nail due to melanin deposition. Remember the 4 “D’s” of pellagra: dermatitis (hyperpigmented rash on sun-exposed regions), diarrhea, dementia, and death. Patients with this finding should be evaluated for renal failure, which commonly coexists. In general, it is rare to develop toxic levels of water-soluble vitamins, as those in excess are excreted in the urine.
• Finally, the most common deficiency to cause nail manifestations is biotin deficiency. While systemic signs of alopecia, myalgias, and paresthesias, brittle nails can develop through dietary lack of eggs, meat, fish, sunflower seeds, and peanuts. Other than nutrient deficiencies, they can be seen in patients who have malabsorptive diseases and alcohol use disorder.

What nail findings are seen with increasing age?

While many nail findings can be physiologic, due to deficiencies in either vitamins or minerals, or associated with systemic disorders, there are others that occur with increasing frequency simply due to progressing age. Examples include brittle nails, onychocryptosis, onychomycosis, and subungual hematomas.

Conclusion

The above patient’s diagnosis was onychomycosis, likely secondary to her poorly controlled diabetes. She was placed on an oral prescription of terbinafine, and she was followed up with 2 months later with resolution of her symptoms. If the symptoms had not improved, then a podiatry consultation could be considered for toenail removal.

The nail is a gateway into the body and can help reveal underlying systemic conditions. It is important not to forget about nail evaluation when performing your general physical exam.