What Is Laugier-Hunziker Syndrome?
Laugier-Hunziker syndrome or LHS is a rare, acquired mucocutaneous hyperpigmentation disease that was firstly described in 1970 by physicians Laugier and Hunziker. It can be defined as an acquired, benign hyperpigmented macular pigmentation of the lips and buccal mucosa. It is not uncommon to find extended mucocutaneous features in this condition, including macular pigmentation of the genitalia in a few affected cases.
What Are the Clinical Manifestations of Laugier-Hunziker Syndrome?
Oral examination by the dentist reveals clinically multiple brown, black, or gray macules, often involving the lips, hard palate, tongue, gingiva, and buccal mucosa. The clinical differential diagnosis may be challenging for this disorder as other accessory systemic linked diseases or disorders also exhibit similar oral pigmentation. They are:
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McCune-Albright syndrome.
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Drug-induced pigmentation.
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Physiologic (racial) pigmentation.
Treatment is not always needed but may be considered for esthetic or cosmetic reasons. The lesions typically in this condition are characterized by the ability to exhibit a smooth surface with lenticular, oval, or irregular-shaped lesions. The macules may be usually small (less than five millimeters in diameter) and discrete, but occasionally if they coalesce, they can form large, confluent areas of pigmentation. Approximately 60 % of patients affected exhibit nail pigmentation seen mainly as longitudinal streaks (longitudinal melanonychia) or a uniformly patterned discoloration of the radial or ulnar half. In some individuals, pigmented lesions may be observed in other sites, such as:
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Skin (especially on the palms and soles).
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Anogenital region.
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Conjunctiva.
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Oropharynx.
What Is the Etiology and Pathogenesis of Laugier-Hunziker Syndrome?
This syndrome has more frequently been reported in the Asian population and has a slightly higher incidence in the Chinese and European populations. Though very rare and fewer than 200 cases have been reported in the literature, case reports have been more prevalent in Europe, with a predilection for white females. The disorder occurs over a broad age range, with a mean age at diagnosis of the approximately fourth decade of life and may attain a peak in the fifth through seventh decades.
Based on gender predilection, a significant female preponderance has been described. Familial cases may follow autosomal dominant as well as recessive traits, both of which may be possible by genetic transmission. The possible hypothesis for the etiology or mechanism for the occurrence of this syndrome is the presence of altered melanocytes in the epidermal layer of skin. The theory accepted is that the L-3,4 dihydroxyphenylalanine melanocytes (reactive) are seen as large dendritic melanocytes in this condition that are capable of increasing melanogenesis.
Is LHS Linked to Systemic Disease?
No underlying systemic abnormalities are associated with Laugier-Hunziker syndrome. Research has also shown no linkage or malignant predisposition existing in relation to this disease. The complete lack of somatic abnormalities has led to the term of just "Laugier and Hunziker pigmentation" rather than a disease entity as per research. However, when this condition is associated with atypical features, the physician can use the term idiopathic lenticular mucocutaneous hyperpigmentation. The characteristic features of this hereditary pigmentary disorder are the unique pigmentation over the mucosal, nail, and acral areas. Nail involvement might be observable in two-thirds of cases and is further classified into 4 types based on the extent of pigmentation, and the dermatologist can diagnose it visually. The condition, though benign, would potentially have a few associations with a few health issues like:
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Esophageal melanocytosis.
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Actinic lichen planus.
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Hypocellular bone marrow.
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Thrombocytopenia.
Hence establishing the correct diagnosis remains of pivotal importance. Hence, this condition represents a rare, acquired mucocutaneous pigmentary disorder of unknown etiology. Due to the close clinical resemblance to serious systemic conditions like Addison disease, Peutz-Jeghers syndrome, Cronkhite-Canada syndrome, and lentiginosis profusa, the physician should consider a diagnosis based on exclusion criterion. The clinical features nearly reveal macular hyperpigmentation on the oral and genital mucosa. They may also be seen in the conjunctiva, palmoplantar region, and longitudinal melanonychia.
How Is Laugier-Hunziker Syndrome Diagnosed?
With Laugier-Hunziker syndrome, a thorough history and clinical examination for signs of fatigue, weight loss, gastrointestinal (GI) involvement are required for differentiation of this condition from other pigmentation associated with certain systemic diseases. Also, after a complete physical examination and routine investigations by evaluation, these tests are done to rule out underlying diseases or disorders. They are:
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Ultrasound.
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Thyroid function test.
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HIV testing.
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Radiographic barium studies.
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Corticotropin or adrenocorticotropic hormone.
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Serum cortisol.
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Electrolytes.
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Liver function tests.
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Endoscopy.
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Screening for cancer.
Upon histopathologic examination of lesions, the pathologist can visualize increased pigmentation in the basal layer with a few dermal melanophages. Electron microscopy reveals multiple mature melanosomes. These melanosomes are contained within keratinocytes and melanophage cells.
How Is Laugier-Hunziker Syndrome Treated?
The goal of therapy is purely cosmetic in cases of LHS or Laugier-Hunziker syndrome. Though no treatment is technically applicable to this condition, cosmetic management of cumbersome lesions and avoiding recurrence of the lesion forms the main goal of the physician, dermatologist, and dentist. Apart from cryotherapy, the lasers used for cosmetic management are:
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Q-switched Nd: YAG laser.
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Q-switched alexandrite laser.
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Erbium: YAG laser.
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CO2 laser.
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Diode laser.
The oral surgeon and the dermatologist can coordinate for laser therapy, whether it is for dermatologic or oral hyperpigmentation. Also, as Laugier-Hunziker has no association with systemic diseases, differential diagnosis needs to be established in cases of systemic involvement.
The pigmentary lesions of Laugier-Hunziker syndrome typically respond poorly to clinical forms of drug therapy, and due to the high recurrence rates, physicians suggest that the patient avoids sunlight following successful therapy. Treatment methods include laser ablation and cryotherapy. Cosmetically disfiguring lesions may be treated with laser therapy. Recurrence is possible but maybe minimized by avoiding exposure to sunlight.
Conclusion:
To conclude, a multidisciplinary team approach is essential to the cosmetic and psychosocial recovery of the patient between the dental surgeons, physicians, and dermatologists to provide or improve the long-term outcomes in patients suffering from this pigmentation.
