Although the cause of most nail pigment changes is benign (such as stains), more serious problems such as cancer must be considered.
Pigmented bands in the nails — known as melanonychia — may or may not represent a significant nail problem. They are to the nail plate what moles or brown-to-black birthmarks are to the skin. Just as the overwhelming majority of moles are benign, the same is true of pigmented bands, which appear as dark lines in the nails extending from the cuticle outward.
Bands in the nails originate in the nail growth center — the matrix — which is located beneath the proximal nail fold,, that portion of the skin next to the cuticle. In dark-skinned individuals, these streaks may be normal in many cases. However, the sudden appearance of a dark streak, a change in its shape or color, or an increase in size could be due to an early malignant change; therefore, the cause of its appearance should be investigated (dark-skinned people tend to have this condition more frequently, but any of these symptoms or changes should be investigated in anyone).
Probably the most common cause of a colored line in the nail is a mole, known as a nevus, in the nail matrix. Most pigmentation authorities today believe that these types of moles require a biopsy — particularly in Caucasians — to rule out the possibility of a malignant lesion or melanoma. Characteristics of nail melanoma include a sudden or very recent appearance of a dark streak that was never present before. In addition, irregular or uneven bands with the color spreading into the nail bed or proximal nail fold are suggestive of malignant melanoma and should be evaluated medically.
The spread into the proximal nail fold is referred to as Hutchinson's sign and is considered a sign of malignancy (until proved otherwise). Just as excessive exposure to the sun may give rise to brown spots on the skin, a similar process is also possible in the nail; however, it usually lakes much less sun exposure to affect the skin than the nail. This is because the nail plate filters out about one-third of the sun's rays, therein" requiring much more exposure to produce the same pigmentation effect.
The nail technician is in a particularly advantageous position to observe nail pigmentation. The onset of these color changes will usually be gradual rather than sudden. Should the nail technician notice a change, she should refer the client to a dermatologist as quickly as possible. The dermatologist will then be able to assess the significance of the color. The doctor can rule out external pigmentation (such as stains that can occur with nicotine or hair dyes, for example), as not serious. Once it is determined that the pigmented bands are benign, the nail technician may treat these nails with the same nail care as unpigmented nails.
However, if the dermatologist orders a biopsy, the client's nails should not be treated until the nail that was biopsied heals, which could take several months.
The biopsy is the most frequent type of test used to diagnose; these bands. Since multiple; bands in multiple nails may be due to a hormone abnormality, the dermatologist may also order some blood tests. Finally, certain medications, such as antibiotics, occasionally can cause nail pigmentation. Therefore, a thorough evaluation should he performed to determine the exact cause of pigmentation.
Nail pigmentation changes could be due to a serious problem, but in most cases they are not serious. A nail professional must know when to refer a client to a physician.