Laugier-Hunziker syndrome is a rare, acquired condition distinguished by hyperpigmentation of the skin and oral cavity. It is a benign disorder that manifests in early to middle adulthood and affects both males and females. The primary characteristics are flat, dark spots on the lips and inside the mouth, as well as distinct bands of color on the nails. This condition is not associated with any systemic diseases or increased risk of cancer.
Identifying the Signs
The signs of Laugier-Hunziker syndrome involve specific changes to the skin and nails. Pigmented macules, which are flat, dark spots, appear on the lips and the buccal mucosa, the inner lining of the cheeks. These spots are brown to black and can vary in size, usually 5 millimeters or less in diameter, though some oral lesions have been reported to reach 1 centimeter. They can present as single spots, groups of multiple spots, or even merge to form larger patches.
Alongside the oral pigmentation, about 60% of individuals also develop nail pigmentation. This feature, known as longitudinal melanonychia, appears as brown or black vertical stripes on the fingernails or toenails. These bands can vary in thickness, between 1 to 8 millimeters, and a person may have one or two bands per nail. In some instances, the pigmentation can cover half of a nail or even the entire nail plate.
Understanding the Cause and Diagnosis
The precise cause of Laugier-Hunziker syndrome remains unknown, classifying it as an idiopathic condition. It is considered sporadic, meaning it occurs without any clear pattern of inheritance, although very rare instances of it affecting multiple family members have been reported. The development of the pigmented spots is related to an increase in melanin production in the affected areas, but the trigger for this change is not understood.
Diagnosis is based on clinical observation and a process of exclusion. A physician will identify the characteristic pigmented macules on the oral mucosa and the distinct nail banding in the absence of any other symptoms or systemic disease. A thorough medical history is taken to rule out other conditions. In some cases, a biopsy (a small skin sample) may be taken from one of the pigmented spots to be examined microscopically, which helps confirm the diagnosis and rule out other possibilities like melanoma.
Distinguishing From Similar Conditions
The most important condition to distinguish it from is Peutz-Jeghers syndrome, which also features dark spots around the mouth. However, Peutz-Jeghers syndrome is a genetic disorder associated with the development of intestinal polyps and a heightened risk of cancer. Laugier-Hunziker syndrome is entirely benign and carries no such risks.
Other conditions are also considered during the diagnostic process. Addison’s disease, for example, can cause hyperpigmentation of the skin and mucous membranes but is accompanied by systemic symptoms like fatigue, weight loss, and low blood pressure, which are absent in Laugier-Hunziker syndrome.
Management and Outlook
Medical treatment is not required for Laugier-Hunziker syndrome. The decision to pursue any form of treatment is based on cosmetic concerns regarding the appearance of the pigmented spots on the lips or skin. The pigmentation inside the mouth and on the nails is left alone.
For individuals who wish to reduce the visibility of the skin macules, a few cosmetic procedures are available. Laser therapy, specifically using Q-switched lasers, has been effective in lightening or removing the spots. Another option is cryotherapy, which involves freezing the pigmented lesions to destroy the excess pigment. Even after successful treatment, there is a possibility that the pigmentation may recur over time. The overall outlook for individuals with this syndrome is excellent, as it does not impact general health or life expectancy.