Skin Glossary - Pathology

• Acantholysis - loss of cohesion between cells of living epidermis, especially stratum spinosum
• Acanthosis - hyperplasia of stratum spinosum
• Adnexa - cutaneous appendages - hair, claws, glands
• Alopecia - abscence of hair in an area where it is normally present
• Anagen - growth phase of hair cycle
• Comedo - plugged and dilated hair follicle
• Crust - accumulation of solid exudate on skin surface, serocellular or haemorrhagic
• Epidermal collarettes - peeling edge of epithelium surrounding an ulcer or erosion
• Erosion - superficial ulcer involvng only epidermis, heals without scarring
• Erythema - reddening of skin caused by congestion of capillaries
• Excoriation - erosions and ulcers caused by self-trauma
• Furunculosis - rupture of hair follicles with severe inflammation
• Hyperkeratosis - increased thickness of stratum spinosum
• Lichenification - thickeningof skin superficial layers with exaggerated crevices
• Macule - circumscribed change in skin colour < 1cm in diameter
• Nodule - solid elevation of skin, >1cm in diameter
• Papule - solid elevation of skin, <1cm in diameter
• Parakeratosis - abnormal cornification, keratinocytes retain their nuclei
• Paronychia - inflammation of tissue fold around nail bed
• Patch - macule > 1cm in diameter
• Plaque - flet topped swelling > 1cm in diameter
• Pustule - small circumscribed elevation containing pus
• Scale - fragments of stratum corneum
• Scar - fibrous tissue area that replaced damaged dermis or subcutaneous tissue
• Seborhea- scaling, crusting and greasiness
• Telogen - resting phase of hair cycle
• Ulcer - break in epidermis with exposed underlying dermis
• Urticaria - vascular reaction in dermis, consists of transient wheals
• Vesicle - blister <1cm in diameter
• Vitiligo - Depigmentation in focal areas where melanocytes are absent