Dermatologic Terminology

1. Dermatologic Terminology

2. Skin • The skin is often known as "the largest organ of the human body". • For the average adult human, the skin has a surface area of between 1.5-2.0 square meters, most of it is between 2-3 mm thick. • The average square inch of skin holds 650 sweat glands, 20 blood vessels, 60,000 melanocytes, and more than a thousand nerve endings.

5. Primary lesions • Most skin diseases begin with a basic lesion that is refererd to as primary lesion. The secondary lesions follow the primary ones. • Macula • Papula • Nodule • Urtica, wheal • Vesicle, bulla • Pustula

6. Macule • flat, nonpalpable circumscribed area of change in the skin. Macules are < 1-2 cm in size.1.Macules may be the result of • (A) hyperpigmentation (e.g. brown as in lentigos), • (B) depigmentation (e.g. vitiligo),  • (C) vascular dilation (e.g. erythema)

7. Red macula • Purpura- lesion caused by extravasated red blood cells (due to vascular or platelet disorder). • Diascopy: the application of pressure with a glass slide on the red lesion. If the redness remains under the pressure of the slide, the lesion is purpuric.

9. Papule: • small solid elevation of skin generally < 5 mm in diameter. • Papules may be: flat-topped, as in lichen planus; • dome shaped, as in xanthomas; • spicular, if related to hair follicles. Papules may result from: • dermal metabolic deposits, • localized dermal cellular infiltrates, • localized hyperplasia of dermal or epidermal cellular elements.

11. Nodule: • palpable, solid, round, or ellipsoidal lesion. • Its depth of involvement and/or palpability differentiate it from a papule rather than its diameter (although nodules are usually larger than papules: > 5 mm diameter). • Nodules can involve any layer of the skin and can be edematous or solid. Based on the anatomical component(s) involved, there are five types of nodules: epidermal, epidermal-dermal, dermal,  dermal-subdermal, and subcutaneous.

13. Lichenification: • Is defined as an inflammatory thickening of the skin with exaggeration of the normal relief and deepening of the natural creases. May be due to persistent scratching. • Itching.

15. Papillomatosis (warty)‏ • An alongation and widening sometimes also branching of the papillary body of the dermis. It is cauliflower-like lesions. The surface consisting of minute finger-like or normal projections.

17. Vesicle (blister): • circumscribed, elevated lesion that is < 5 mm in diameter containing serous (clear) fluid. • Bulla: A vesicle with a diameter > 5 mm.  • Fluid can be accumulated within or below the epidermis.

18. subcorneal vesicle - fluid just below stratum corneum, extremely fragile leading to crushing intraepidermal vesicleacantholytic vesicles) - cleavage within epidermis due to intercellular attachment loss, • Subepidermal vesicle due to changes in dermal-epidermal junction. Vesicles have arisen on normal or erythematous skin.     

20. Pustule: • superficial, elevated lesion that contains pus (pus in a blister). • Pustules may vary in size and shape. • The color may appear white, yellow, or greenish-yellow depending on the color of the pus. • Pus is composed of leukocytes with or without cellular debris. It may also contain bacteria (non sterile) or may be sterile (leukocytes only).

22. Urtica, wheal: • Is a flattopped elevated lesion due to edema in the upper dermis. The epidermis is not affected. Wheals are transient and may last only a few hours. • Wheals can be pale red or white (especially in the center) if edema is sufficient to compress superficial vessels. Wheals are a common allergic reaction. • usually itches.Angioedema: is a deep, edematous urticarial reaction that occurs in areas with very loose dermis and subcutaneous tissue (lips, eyelids).

24. SECONDARY LESOINS • Result from the natural evolution of primary lesions (eroded area left by bursting vesicle) or from the patient's manipulation of the primary lesion (scratching).   • Scale • Crust • Erosion • Fissure, rhagas • Eschara • Ulcer

25. Scale: • accumulation or abnormal shedding of horny layer keratin (stratum corneum) in perceptible flakes. The change may be primary or secondary. Scales usually indicate inflammatory change and thickening of the epidermis. The may be fine, as in pityriasis; white and silvery, as in psoriasis; or large and fish-like, as in ichtyosis. • Scales: dry or oily (greasy)

27. Crust: • dried serum, blood, or pus on the surface of skin. Crusts are yellow, if from serum; green or yellow-green if from pus; or brown or dark red if formed from blood. Crusts that occur as honey-coloured, delicate, glistening particulates are typical of - Impetigo.

29. Erosion: • A focal loss of epidermis • erosion do not penetrate below the dermoepidermal junction and therefore heal without scaring. • Excoriaton is a shallow abrasion often caused by scratching. • Erosion follow blisters or papula

31. Fissura, rhagas: • Is a linear cleavage or cracks of epidermis and dermis with sharply defined nearly vertical walls. It is linear split at an orifice (angle of the mouth or anus), or along a shin crease due to dry skin palms and soles). They may be painful.

33. Eschara: • Well defined or circumscribed necrosis skin due to trauma (burning, frostbite, freezing, chilblain), or ischemia in vascular disorder (DM, microangiopathy). Color is black.

35. Ulcer: • circumscribed area of skin loss extending through the epidermis and at least part of the dermis (papillary). • Basically, it's a "hole in the skin". • Ulcer is healing with scaring.

36. Morphology of ulcer: • Site • Number • Size (cm)‏ • Shape • Depth (mm)‏ • Base • Border • Surrounding skin

38. Scar, cicatrix: • A permanent fibrous skin lesion, healed dermal lesion secondary to trauma, surgery, infecion. Skin appendages are absent. Scars may are atrophic or hypertrophic

39. Atrophy: • Depresion of the surface caused by regressive changes involving the thinning of the epidermis or dermis and loss of the skin appendages, blood vessels are easilly seen under the skin, often the fine surface is wrinkling.

41. Rigid atrophy, sclerosis: • Hard atrophy often adhering to • the tissue below, skin appendages are absent, the surface is mirror-like

42. Elephanthiasis: • A shapeless swelling and thickening due to chronic lymphatic obstruction and reactive fibrosis, inflammation with connective tissue proliferation.

44. Impregnation: • The deposition ion the skin of alien particles ( ink – tatoo, gold – chrysiasis)‏

45. Incrustation: • The deposition in the skin of proper particles ( calcium salts – calcinosis)‏

46. DISTRIBUTION • Solar • Seborrhoeic • Intertriginous • Embolic • Predilection

47. Solar: • Site of exposure to sunshine – the face (nose, ears, forehead, cheeks,), neck, upper part of the sternum, dorsum of the hands • Disorders: photodermatosis, lupus erythematosus, porphyria

49. Seborrhoeic: • Regions containing large sebaceous glands – centrofacial area – forehead, nose, nasolabial folds,), sternal and interscapular regions, shoulders • Disorders: acne, seborrhoeic dermatitis, seborrhoeic warts

50. Intertriginous: • Regions of the skin folds – the axillae, submammary, folds of the neck, intergluteal fold, interdigital, inguinal regions • Disorders: candidosis, intertrigo, napkin dermatitis, mycotic infection