MORPHOLOGY OF SKIN LESIONSDr. Riaz Uddin AhmedMBBS, DDV, MCPS, FCPSAssociate Professor of DermatologyBangladesh Medical College

A. Primary lesions- The original lesions are known as primary lesion which are as follows:Macule, patchPapule, plaque, nodule, tumorWheals VesicleBullaePustule

B. Secondary Lesions: the primary lesions continue to full development or may be modified by regression, trauma of other extraneous factors, producing secondary lesion which are as follows:ScalesCrustsExcoriations and abrasionsFissuresErosionsUlcersScar-hypertrophic scarsKeloidAtrophyCyst

C. Special Lesion: lesions that are produced special circumstances of body system which are as follows:Erythema-Erythema multiforme, erythema nodosumTelangiectasiaPurpuraPetechiaeEcchymosesVibicesHaematomaErythroderma (exfoliative dermatitis)

A. Primary LesionsMucule- Latin: macula, spot Macules are variously sized, circumscribed changes in skin color, without elevation or depression and less than 1 cm in diameter

MaculePapule

Patch: A patch is a circumscribed changes in skin color without elevation or depression and 1 cm or greater in diameterPapule- (Latin Paula, Pimple)Papules are circumscribed, solid elevations of skin having diameter less than 1 cm

Plaques: (French- Plaque- Plate)A plaque is a broad papule (or confluences of papules), 1 cm or more in diameter.

NodulePlaqueCrust

VesiclePustuleWhealScaleErosion

ErythrodermaHypertrophic Scar

Keloid

Purpura

Nodules (Latins: nodulus- small knot)- Nodules are form of papules but largest (>1 cm) and invade deeply.

Tumors

Tumors are soft or firm and freely movable or fixed masses of various sizes and shape. A tumor is an abnormal mass of tissue, the growth of which exceeds and un-coordinated with normal tissue and persists in the same excessive manner after cessation of stimulus which evoked the change.

Wheals (Hives) wheals are evanescent, oedematous, flat elevations of various sizes.

Vesicles (Latin Little bladder) vesicles are circumscribed epidermal elevations 1-10 mm in size and usually containing clear fluid.

Bulloe (Latin-Bubble)- Bulloe are circumscribed or irregularly shaped cavity more than 10 mm in diameter containing serous or seropurulent fluid.

Pusteules (Latin- Pustula-Pus)- pustules are small elevations of the skin containing pus

Secondary LesionsScales: (Latin Squama-scales)- scales are dry or greasy laminated masses of keratin.

Excoriations (Latin Abrasio)- an excoriation is a punctate or linear abrasion produced by mechanical means usually involving only the epidermis and rarely reaching the papillary layer of the dermis.

Fissures (Latin- Cracks)- a fissure is a linear cleft through the epidermis or rarely into the dermis caused by disease or injury

Erosions loss of all or portion of epidermis alone

Ulcers (Latin- Ulcus- Sore)- ulcers are rounded or irregularly shaped excavations that result from loss of epidermis and dermis.

Crusts (Latin- crusta-bark)- crusts are dried serum, pus or blood, usually mixed with epithalial and bacterial debris.

Scars ( )- scars are new formations in the dermis or deeper parts as a result of injury or disease, as a part of the normal reparative and healing process scar may be hypertrophic.

Keloid (Latin- Cheloid-clawlike)- a keloid is a firm, irregularly shaped, thickened, hypertrophic, fibrous, pink or red excrescence.

Hypertropic ScarKeloidClaw-like prejections absentThere is claw-like projections present in Keloid Hypertrophic scar does not extend beyond the original woundKeloid extend and spread beyond the limits of the original injury In hypertrophic scar, there is sponteneous improvement within first six monthsSponteneous improvement does not occur in Keloid

UlcerScarAtrophy

Atrophy: this refers to a diminuation of some or all layers of kin

Cyst: a cyst is a cavity containing liquid or solid or semi-solid material may be superficial or deep.Cyst

SPECIAL LESIONS

Erythema: erythema may be defined as redness of skin due to dilatation of blood vassals which may be localised or wide spread near the surface of the skin.

Erythema multiforme: erythema multiforme is a mucocuteneous in which various types of skin reaction may occur from the same causative agents and conversely many causative agents may induce same cutaneous and mucous membrane reactions.

Erythema nodosum: erythema nodosum is an inflammatory but non-suppurative condition of the skin characterized by erythematous, tender nodules, usually located over extensor aspects of lower limbs.

Erythroderma: erythroderma isa terminal condition of any inflammatory disorder which affects either universally or more than 90% body surface area characterised by erythema, oedema, scaling, thickening and itching chilliness caused by idiopathic, drug or secondary to some reactional process to an underlying systemic or cutaneous dermatosis.

Telengiactasia: permanent dilatation of blood vassals is known as Telengietasia.

Purpura: purpura may be defined as bleeding in the skin and mucous membrane from the capillary at the arterio-capillary junction which does not blanch on pressure and has progressive colour change.

Petechiae- are superficial, pinhead sized (less than 3 mm), round, haemorrhagic macules, bright red at first then brwonwish or rust coloured.

Ecchymoses: siguify a deeper and extensive inter stitial haemorrhage, which forms a flat irregularly shaped, bluists-purplish patch.

Vibices (singuler-vibex) are linear purpuric lesions.

Haematoma: designates a pool-like collection of extravasated blood in a dead space in tissue that, if of sufficient size, produces swelling that fluctuates on palpation.