A

abscess
A localized accumulation of pus in the dermis or subcutaneous tissue. Frequently red, warm, and tender.
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acuminate
Pointed.
advancing edge scale
See leading edge scale.
alopecia
Partial of complete hair loss.
angioedema
 Dermal, subcutaneous, or submucosal swelling caused by excessive interstitial fluid. It may involve the face, neck, lips, larynx, hands, feet, genitalia, or other areas.
annular
Ring shaped.

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anonychia
Absence of one or several nails.
aphthous ulcer
A sharply marginated, shallow, painful mucosal ulceration.
arcuate
Arc shaped.
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asymmetric
1. Pertaining to an individual lesion: Unequal shape from side to side. 2. Pertaining to a body distribution: Unequal distribution of lesions on both sides of body.
atrophy
A thinning of tissue modified by the location, e.g., epidermal atrophy, dermal atrophy, or subcutaneous atrophy.

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B
Beau's lines
Transverse depressions or grooves in the nail plate typically occurring at corresponding positions within each nail plate. Often a sign of a prior severe illness such as malnutrition,
a systemic disease, or trauma.
bilateral
Occurring or appearing on both sides of the body, e.g., left and
right arm.
Blaschko lines
A skin pattern due to developmental processes usually consisting of bands or whorls that do not follow vascular or neural structures.
brachyonychia
(racquet nail)
The width of the nail bed and nail plate is greater than the length.
bulla
 A fluid-filled blister greater than .5 cm in diameter.  Fluid can be clear, serous, hemorrhagic, or purulent.

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