I
ichthyosiform scale
Large polygonal scales, as in fish scales.

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imbricated
Resembling tiled roof.
indurated
Hardening of the skin beneath the epidermis usually caused by edema, dermal-sclerosis, inflammation, or cellular infiltration.
infarct
Area of necrosis resulting from lack of blood supply.
inframammary
Area involving the skin folds below the breasts.
intertriginous
Regions where opposing skin surfaces come in contact that may cause friction, e.g., axillae and inner thighs.
iris
Concentric rings of various color shades.
irregular
Not of regular or symmetrical form; unevenly shaped or placed.
K
keloid
A firm, usually elevated, proliferation of scar tissue exceeding the area of the preceding skin injury or wound.

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keratoderma
A diffuse, usually persistent, retention of stratum corneum producing a thick, waxy layer of yellow adherent keratin. Keratoderma typically involves the palms and soles.
koilonychia
Concave and slightly spoon shaped nails.
L
lakes of pus
Coalescing areas of pus.
lamellar scale
Plate-like scale.
leading edge scale
Scale at the advancing edge of a plaque. Also called advancing edge scale.
leukonychia
(true leukonychia)
White coloration of the nail plate, either partial or total involvement.
lichenification
Thickened skin with accentuated markings usually due to repeated rubbing and scratching of skin.

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linear
Resembling a straight line.

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localized
Process limited to a discreet area of the body.
lunula
A crescent-shaped pale area corresponding to the distal matrix at the proximal nail.
lymphangitic
Following the lymphatic vessels.