Laugier-Hunziker Syndrome Workup

Updated: Jun 27, 2019
  • Author: Christen M Mowad, MD; Chief Editor: Dirk M Elston, MD  more...
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Workup

Laboratory Studies

Laugier-Hunziker syndrome (LHS) is a diagnosis of exclusion. When the diagnosis of Laugier-Hunziker syndrome is suspected, tests should be performed to rule out other differential diagnoses.

The corticotropin level is elevated in patients with Addison disease associated with primary adrenal failure. The morning cortisol level is low, and corticotropin stimulation results are abnormal. In addition, electrolyte abnormalities, including hyperkalemia and hyponatremia, may be observed. Significant electrolyte abnormalities may be absent, and the serum potassium level is not sensitive enough to use as a screening test for Addison disease. Patients with Addison disease often report salt cravings, weight loss, and fatigue. Physical examination may reveal hypotension, pigmentation of the buccal mucosa and nails, generalized hyperpigmentation, or darkening of nevi and scars.

The antinuclear antibody (ANA) test is useful to screen for connective tissue diseases, including lupus erythematosus, which may cause buccal and lip hyperpigmentation. Nail streaks have not been reported in patients with lupus. Sjögren syndrome, subacute cutaneous lupus erythematosus, Coombs positive–autoimmune hemolytic anemia, and inflammatory arthritis have occurred in some patients with Laugier-Hunziker syndrome. The significance of comorbid connective tissue disease and Laugier-Hunziker syndrome is currently unknown.

STK11 gene testing may be performed to evaluate for Peutz-Jeghers syndrome. [22, 23]

Liver function test results are abnormal in hemochromatosis.

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Imaging Studies

Radiographic barium contrast studies are performed to rule out gastrointestinal polyposis in association with PJS. Most commonly, hamartomas of the jejunum are present in PJS, but they may be present anywhere throughout the gastric, intestinal, and colonic mucosae.

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Other Tests

Dermatoscopic findings have been reported and include the following [24, 25] :

  • Mucosa - Parallel patterns of pigmentation

  • Nails - Longitudinal, homogeneous, regular, bandlike pigmentation with indistinct borders

  • Palmar/plantar skin - Parallel, furrowed hyperpigmentation

  • Vulva - Parallel pattern with partially linear and partially curvilinear, light to dark brown streaks

  • Lips - Linear streak like brown pigmentation caused by skin furrows and reliefs associated with multiple brown dots of different sizes distributed regularly throughout the lesion [24]

Dermatoscopic findings vary widely given the different locations involved. Further evaluation of these findings is needed to better establish dermatoscopic criteria for this condition.

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Procedures

Endoscopy may be performed in lieu of, or in addition to, radiographic barium contrast studies to rule out PJS.

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Histologic Findings

Biopsy specimens from the oral and esophageal mucosa and from keratinized skin have been studied. Nail biopsies are rarely performed in the setting of multiple pigmented bands; therefore, nail histology has not been described.

The pigmented macules of Laugier-Hunziker syndrome are not lentigines. They demonstrate mild-to-moderate acanthosis in most cases. [3] The predominant finding is basal cell hypermelanosis. The melanin deposition in the basal layer is dense and uniform. Rete ridges may be normal in size, or they may be elongated. Numerous melanophages are often present in the papillary dermis. The basement membrane has been found to be intact. Pigment incontinence may also be present. [3]

Although the absence of melanocytic proliferation has been a typical pathologic feature, recent studies recently noted an increase of nonnested intraepidermal melanocytes in the areas of clinical hyperpigmentation using S100 and L-3,4 dihydroxyphenylalanine immunohistochemistry studies. [1, 7]

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