Melanonychia, Commonly Called Black Toenail
Although trauma is considered the most common cause of black toenail, other medical conditions should not be dismissed.
Occasionally these conditions can be as severe as cancer of the toenail and if overlooked may lead to grave consequences.
Melanonychia is a dermatologic condition which refers to the black or brown pigmentation of the nail, which is not necessarily due to deposition of melanin in the toenail.
Melanin is a pigment in the human body, giving black color to different parts of the body.
The common causes for this color include: melanocytic activation, lentigo, nevus, melanoma, hemorrhage, pigment deposition due to fungal or bacterial infections, and other exogenous causes like cigarette smoking.
Occasionally it becomes difficult to differentiate between the hemorrhage beneath the nail and a melanoma (tumor of the nail).
Traumatic hemorrhage beneath the nail is the more common condition and is usually confused with the hemorrhage which may also occur in a melanoma.
Therefore to differentiate between these conditions one needs to be thorough and meticulous in order to avoid missing the correct diagnosis.
A study has revealed melanonychia is more common in darkly pigmented people as compared to Caucasians.
It is seen in the most commonly used digits like the big toe (hallux), thumb and index fingers.
In case of cutaneous pigmentation, melanonychia can be constant or progressing, regular or irregular, homogenous or heterogeneous and it may be congenital or acquired.
A theory presented by Robert Baran showed that the black color of the nail is also termed as 'frictional melanonycia' because it usually occurs due to physical stimuli like rubbing, directly to the proximal nail apparatus and triggers melanocytic activation.
This activation imparts the black color to the toenail.
Addison's disease is another common condition causing hyperpigmentation of the toenail.
it occurs because of the increased levels of melanocyte stimulating hormone levels.
This hormone stimulates the cells which impart black color to the nail.
The diagnosis of this nail condition is complex.
This is due to the fact that a melanoma (cancer) of the nail can have a similar appearance to other, less serious conditions, so a thorough examination including a proper medical history, should be taken at the onset, detailing the progression and timing of the pigmentation.
Progressing pigmentation provides a clue to whether the blackening is caused by a melanoma.
A definitive diagnosis lies on the histopathological examination of a biopsy sample taken from the nail.
The treatment of black toenail in these conditions is dictated by the causing factor.
Occasionally these conditions can be as severe as cancer of the toenail and if overlooked may lead to grave consequences.
Melanonychia is a dermatologic condition which refers to the black or brown pigmentation of the nail, which is not necessarily due to deposition of melanin in the toenail.
Melanin is a pigment in the human body, giving black color to different parts of the body.
The common causes for this color include: melanocytic activation, lentigo, nevus, melanoma, hemorrhage, pigment deposition due to fungal or bacterial infections, and other exogenous causes like cigarette smoking.
Occasionally it becomes difficult to differentiate between the hemorrhage beneath the nail and a melanoma (tumor of the nail).
Traumatic hemorrhage beneath the nail is the more common condition and is usually confused with the hemorrhage which may also occur in a melanoma.
Therefore to differentiate between these conditions one needs to be thorough and meticulous in order to avoid missing the correct diagnosis.
A study has revealed melanonychia is more common in darkly pigmented people as compared to Caucasians.
It is seen in the most commonly used digits like the big toe (hallux), thumb and index fingers.
In case of cutaneous pigmentation, melanonychia can be constant or progressing, regular or irregular, homogenous or heterogeneous and it may be congenital or acquired.
A theory presented by Robert Baran showed that the black color of the nail is also termed as 'frictional melanonycia' because it usually occurs due to physical stimuli like rubbing, directly to the proximal nail apparatus and triggers melanocytic activation.
This activation imparts the black color to the toenail.
Addison's disease is another common condition causing hyperpigmentation of the toenail.
it occurs because of the increased levels of melanocyte stimulating hormone levels.
This hormone stimulates the cells which impart black color to the nail.
The diagnosis of this nail condition is complex.
This is due to the fact that a melanoma (cancer) of the nail can have a similar appearance to other, less serious conditions, so a thorough examination including a proper medical history, should be taken at the onset, detailing the progression and timing of the pigmentation.
Progressing pigmentation provides a clue to whether the blackening is caused by a melanoma.
A definitive diagnosis lies on the histopathological examination of a biopsy sample taken from the nail.
The treatment of black toenail in these conditions is dictated by the causing factor.
