EpistemisLongitudinal melanonia
Specialty: Skin.
Why it occurs
- Benign melanocytic activation or lentigo of the nail matrix (common in people with high phototype as a physiological variant)
- Repetitive trauma or chronic friction on the nail matrix
- Subungual onychomycosis with pigment production by dematiaceous fungi
- Drug-induced hyperpigmentation (chemotherapeutics such as doxorubicin, or antiretrovirals such as zidovudine)
- Subungual melanoma (malignant neoplasm derived from melanocytes of the nail matrix).
Initial workup
Nail dermoscopy (onychoscopy) performed by a specialist to evaluate the regularity of the pigmented lines and rule out the micro-Hutchinson sign, and incisional or excisional biopsy of the nail matrix directed by dermatoscopy (gold standard for pathological diagnosis).
red flags
Pigmented band with a width greater than 3 mm, presenting diffuse borders or variability in color tones, distortion or destruction of the associated nail plate, extension of the pigment towards the proximal or lateral nail fold (Hutchinson's sign), or exclusive involvement of a single finger in a patient with a light phototype.
Standard management
- Avoid drugs that trigger hyperpigmentation if clinically viable
- Specific antifungal treatment with oral itraconazole — through pulse therapy of 400 mg/day one week a month if colonization by pigmented fungi is confirmed
- It does not require pharmacological therapy if malignancy and infection are ruled out, and is limited to close clinical surveillance.
Educational guidance for study. It is NOT a prescription recommendation. The actual choice depends on the cause, the patient, and current guidelines.
- Area
- Skin
- Listed causes
- 5
- Treatment options
- 3