Basic Skin Lesions
📌Classification
📍Primary lesions📍Secondary lesions
📍Special lesions
📍Primary Lesions
Macule
Papule
Nodule
Plaque
Vesicle
Bulla
Pustule
Cyst
Scale
Crust
Erosion
Ulcer
Excoriation
Fissure
Sinus
Scar
Lichenification
Atrophy
📍Special lesions
Erythema/Purpura
Wheal
Burrow
Comedone
Milium
Telangiectasia
Sclerosis
Poikiloderma
Target lesions
Macule
Definition: Circumscribed alteration in the colour of the skin of any size orshape that is non-palpable and without depression and has no alteration in
the skin texture or scaling within the lesion
Macule > 1-2cm in diameter is “LARGE MACULE”
Macule > 2cm in diameter is “AREA”
Margins can be well defined or ill defined
Shape can be circular, oval, or irregular
Colour of Macule : Erythematous, Hypopigmented (e.g. Nevus
hypochromicus), Hyperpigmented (e.g. Melasma), depigmented (e.g. Vitiligo)
Depigmented and hypopigmented macules
Papule
Definition : Small, solid, elevated, palpable lesion up to 0.5 cm in size formedeither by localized proliferation of tissue cells or infiltration with
inflammatory cells.
Papules sized 1-2 mm are called “Micropapules”
Shape : Sessile, Pedunculated, Dome-shaped, Flat-topped,Filiform, Acuminate,Umbilicated
Colour : Varies:-
*Brownish : Verruca vulgaris
*Yellowish orange : Xanthoma
*Violaceous purple : Lichen planus
*Pearly white : Molluscum Contagiosum
*Blue-black : Malignant melanoma
Surface : Rough or smooth surfaced
Examples : Warts (Rough surface), Lichen nitidis (micropapules), Mollascum
contagiosum (Umblicated)
Nodule
Definition : Solid, elevated, palpable lesion >0.5 to 1 cm in size formed eitherby localized proliferation of tissue cells or infiltration with inflammatory cells.
A nodule sized >1.0 cm is better be called a “Large nodule”
Shape : Ellipsoid or Globular, Pedunculated or Sessile
Surface : Smooth, Keratotic, Ulcerated, or Fungating
Types : Depending anatomical component involved -Epidermal, Epidermal-dermal, Dermal,Dermal-subdermal or Subcutaneous
Other features : Depending on underlying pathology –Warm, Hard, Soft, Fluctuant, Tender, Movable, or Fixed
Examples : Neurofibroma, Leprosy,Erythema nodosum
Papules and Nodules of varied Morphology
and Size in neurofibromatosis
Shiny, Pearly Umblicated Papules
in Molluscum contagiosum
Plaque
Definition : Solid, elevated, palpable lesion >1 cm in diameter with a flat
plateau like surface.
Plaque sized >2cm are “Large plaques”
Shape : Round, Oval, Discoid (uniformly thickened), or Annular with regular
or irregular borders
Types : Depending on anatomical component involved –Epidermal, Epidermal-dermal, Dermal,Dermal-subdermal or Subcutaneous
Surface changes : Depending on underlying pathology –Scaling, Necrosis, Erosion, Ulceration, Crusting, Eschcar formation
Examples : Psoriasis, Leprosy, Granuloma annulare
Well-defined, erythematous, scaly
large plaques of psoriasis vulgaris
Annular Plaques in Leprosy
Vesicles and Bulla (Blister)
Definitions :Vesicle: An elevated fluid-filled lesion sized < 1 cm
Bulla: Fluid filled lesion sized > 1 cm
Formation : Vesicles or bullae arise from the cleavage at either intraepidermal or sub epidermal level by formation of cavity and collection of fluid
In Bulla, the fluid in the cavity exerts equal pressure in all directions giving spherical shape
Contents of vesicle: Clear, Serous, Turbid,Haemorrhagic
Examples : Herpes simplex, Pemphigus,Scalds, Bullous pemphigoid, eczema
Pustule
Definition : A circumscribed raised Pus filled lesion.
Pustules may vary in size and in certain conditions like pustular psoriasis they may coalesce to give “lake of pus” appearance
Purulent exudate contain : either cellular debris, leukocytes, or bacteria or may be sterile
They can be located at the opening of hair follicles as in folliculitis
Pustules are superficial- heal without scarring
Examples : Bacterial (folliculitis), Pustular psoriasis
Cyst
Definition : A closed cavity or sac (normal or abnormal) that has an epithelial, endothelial ormembranous lining and contain fluid or semisolid material
Examples : Sebaceous cyst, Epidermal cyst (Milia), Pilar cyst
Abscess
Definition : It is localized accumulation of pus deep in dermis or sub cutis. Usually not visible onthe surface of skin.
It is erythematous, warm, tender, fluctuant nodule
From Staphylococcal, Streptococcal infections
Scale
It is visible exfoliation of flake of stratum corneum
Morphology varies with type of skin disease:-
Examples :–
Silvery, loose scales - Psoriasis
Fine powdery scales - Pityriasis versicolor
Fish-like scales - Ichthyosis
Collarette scales - Pityriasis rosea, Seborrhoeic dermatitis
Ichthyotic Scales
Crust
Crust is dried up exudates (blood, serum, pus)
Removal of crusts leave moist surface/ erosion beneath
Colour of crust varies with nature of exudate:
Yellow-brown - dried serous secretions
Turbid yellow-green - purulent secretion
Reddish black - hemorrhagic secretion
Hemorrhagic Crusts
Erosion
Raw, moist lesion left from a complete or partial loss of epidermis or mucosal epithelium
Results from trauma, rupture of vesicles or bullae, or epidermal necrosis
Heal without scar unless secondarily infected
Examples : in Pemphigus, SJS-TEN
Ulcer
Ulcer forms from breach and destruction of skin (epidermis, dermis with basal layer, adnexal structures) or Mucosa
Heals with scarring.
May be superficial or deep.
Margins of ulcer :-
overhanging -tubercular
Punched out - gumma
Light pink granulation tissue at floor-Indicate healing
Excoriations
Linear or circumscribed erosions formed from surface excavations of epidermis due to scratching
Frequent finding in patients having disorders with pruritus
Linear and punctate excoriations on the back induced by scratching.
Fissure
It is a linear, triangular crack in the skin/mucosa
Results from excessive tension or decreased elasticity of the involved tissue
Can be superficial or deep
Deep fissures are painful
Common over palms and soles due to thick Stratum corneum
Examples : In Palmoplantarpsoriasis, Keratodermas, Irritant CD,Fissures of heels
Sinus
It is a tract connecting a deep cavity to the surface of the skin
Contents of the deep cavity are usually pus, epithelial debris.These contents drain to the surface when such a channel exits
Eg:-Multiple sinuses in Nocardiosis
Scar
It is the proliferation of fibrous tissue that replaces the normal collagen after the ulcer involving the reticular dermis heals
Epidermis is thinned and wrinkled, and adnexa like hair are destroyed
Hypertrophic scars : typically take form of plaques or nodules. It does not grow beyond the limit of original lesion
Keloid : exceeds the limit of original lesion
Lichenification
Definition : Thickening of skin due to repeated and prolonged rubbing/scratching of skin characterized by:-*Thickening of epidermis/dermis
*Accentuated of skin markings
*Hyperpigmentation
Examples : Lichen simplex chronicus
(LSC), Lichenified chronic (atopic) dermatitis
Atrophy
Definition : A loss of cutaneous mass from diminution in size of any of thecomponents of skin.
*Epidermal atrophy: Glossy,transparent, cigarette-paper like thinning and wrinkling, loss of normal skin lines
*Dermal atrophy: Circumscribed area of depressed skin, normal in colour and surface
*Subcutaneous atrophy: Substantial depression of skin
Erythema and Purpura
Erythema : Blanches redness of skin, and is due to vascular congestion or increased perfusion e.g. Facial erythema in RosaceaPurpura : Non-blanching reddish to purple discolouration of skin due to extravasation of RBCs in dermis e.g.Vasculitis, Bleeding disorders
Petechiae : 1-2 mm small pupuric lesions,
Occur in crops e.g. Clotting disorders
Ecchymosis : Larger purpuric lesions fromextrvasation of blood
Diascopy : differentiates erythema frompurpura
Wheal (Hives, Urticaria) & Angioedema
Definition : An evanescent (lasting 48-72 hrs) erythematous, elevated lesion due to edema of dermis (Wheal) frequently with central pallor, or dermo-hypodermis with loose dermal tissue e.g. lips, eyelids, scrotum (Angioedema)
Results due to vasodilatation and increased permeability of dermal capillaries leading to edema
Specific of Urticaria
Burrow
Definition : It is wavy, thread like tunnel excavated in the stratum corneum by Scabies mite
It measures only few mm in length
Characteristic of Scabies and particularly seen over palms and soles,wrists, and genitalia in infants and very young children
Comedo
Definition : A dilated pilosebaceous orifice plugged by keratin and sebum
Open Comedo : Pilosebaceous opening is open to the surface of skin by black keratinous plug
Closed Comedo : Closed pilosebaceous opening is unapparent, accumulates the whitish keratin
Characteristic and primary lesion of acne
Milium
Definition : A tiny white superficial cyst with epidermal lining containing lamellated keratin.
Sometimes arise on blistered or damaged skin e.g. after dystrophic epidermolysis bullosa, Porphyria,Dermabrasion.
Telangiectasias
Definition : Visible and persistent dilatations of small capillaries in the superficial dermis that appear as fine, bright non-pulsatile, net like pattern on the skin
May or may not disappear with diascopy
Types : Mat-like, Punctate, Linear
Examples : In - rosacea, Collagen vascular diseases
Sclerosis
Definition: A diffuse induration and hardening of skin due to dermal fibrosis.The skin feels firm board like, immobile and difficult to pick up
Examples: Morphea, Systemic sclerosis.
Poikiloderma
Definition : A dappled appearance of skin from combination of atrophy, telangiectasia, and pigment changes (hypo or hyperpigmentation)
Example : Rothmund Thompson syndrome, Xeroderma pigmentosa
Target Lesions
Definition : These have 3 zones:Central: dusky, blistered or purpuric zone
Middle: pale zone of edema
Outer: Erythematous zone with well defined edge
No comments:
Post a Comment