Laboratory Studies
An elevated serum immunoglobulin E level occasionally supports the diagnosis of an underlying atopic diathesis. Perform potassium hydroxide examination and fungal cultures to exclude tinea cruris or candidiasis in patients with genital lichen simplex chronicus.
Other Tests
Patch testing helps exclude allergic contact dermatitis as an underlying primary dermatosis (eg, allergic contact dermatitis to nickel with secondary lichen simplex chronicus) or as a factor in chronicity (eg, allergic contact dermatitis to topical corticosteroids used to treat lichen simplex chronicus).
Procedures
Frequently, skin biopsy is performed to exclude other disorders, particularly psoriasis or mycosis fungoides (cutaneous T-cell lymphoma) in elderly patients. [22]
Histologic Findings
Histologic examination demonstrates hyperkeratosis, acanthosis, spongiosis, and patches of parakeratosis in the epidermis. Epidermal thickening of all layers is noted, with elongation of rete ridges and with pseudoepitheliomatous hyperplasia. Papillary dermal fibrosis with vertical streaking of collagen bundles is characteristic.
A characteristic finding of lichen simplex chronicus that is noted on electron microscopy is frequent collagen fibers attached to and just above the lamina basalis.
Increased numbers of blood vessels can be encountered. “Prurigiform angiomatosis" has been suggested as a term to describe this pattern of epidermal hyperplasia with prominent dermal angioproliferation. [23] Mechanical trauma and inflammation along with epidermal vascular endothelial growth factor expression are thought to play a causative role. [23]
H and E biopsy of lichen simplex chronicus from forearm skin viewed at 40x magnification. Note the characteristic hyperkeratosis, hypergranulosis, pseudoepitheliomatous hyperplasia, and papillary dermal fibrosis.
H and E biopsy of lichen simplex chronicus from forearm skin viewed at 100x magnification. Note the characteristic hyperkeratosis, hypergranulosis, pseudoepitheliomatous hyperplasia, and papillary dermal fibrosis.
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Plaque of lichen simplex chronicus demonstrating accentuated skin markings. Courtesy of San Antonio Uniformed Services Health Education Consortium Dermatology Program.
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Area of lichen simplex chronicus originally believed to be chronic contact dermatitis. The true nature was revealed when the patient admitted to rubbing this area while watching television. Courtesy of San Antonio Uniformed Services Health Education Consortium Dermatology Program.
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Plaques of lichen simplex chronicus on the hand.
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Lichen simplex chronicus of the dorsal hand and wrist demonstrating increased skin thickness and accentuation of skin markings.
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Plaque of lichen simplex chronicus of the leg with accentuated skin markings and excoriations.
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H and E biopsy of lichen simplex chronicus from forearm skin viewed at 40x magnification. Note the characteristic hyperkeratosis, hypergranulosis, pseudoepitheliomatous hyperplasia, and papillary dermal fibrosis.
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H and E biopsy of lichen simplex chronicus from forearm skin viewed at 100x magnification. Note the characteristic hyperkeratosis, hypergranulosis, pseudoepitheliomatous hyperplasia, and papillary dermal fibrosis.
