basic skin lesions in dermatology

1. TYPES OF SKIN LESIONS
By: Dr. Mohd Mujahed Rizwan

2. Basic lesions are classified into three categories
PRIMARY LESIONS: They are which develop as a direct result of
the disease process.
SECONDARY LESIONS: They are those which evolve from primary
lesion or develop as a consequence of the patient’s activities.
SPECIAL LESIONS: They are diagnostic to a particular disease.

3. PRIMARY
LESIONS
Macule
Papule
Plaque
Nodule
Wheal
Angioedema
Vesicle
Bulla
Pustule
Cyst
Abscess
Purpura, petechiae and ecchymosis

4. SECONDARY
LESIONS
Crust
Excoriations
Erosions
Ulcer
Scar
Scale

5. SPECIAL
LESIONS
Burrow
comedone
Milium
Telangiectasia
calcinosis

6. PRIMARY LESIONS

7. MACULE
A macule is a circumscribed flat lesion characterized by alteration in skin colour, of any size or
shape.
They are further subclassified based upon their colour as
• Hypopigmented or depigmented macule
• Hyperpigmented macule
• Erythematous macule

8. HYPOPIGMENTED OR
DEPIGMENTED MACULE
A decrease in the number of melanocytes or melanin results in a
hypopigmented macule.
They are seen in conditions like:
• pityriasis alba
• pityriasis versicolor
• vitiligo
• leprosy

9. HYPERPIGMENTED MACULES
These are produced by an excess of melanocytes or melanin in
the skin.
• Increased melanin in the epidermis, in freckles and melasma
gives it a brown to black colour.
Melanin present in the dermis produces a bluish grey tinge
which can be seen in conditions like
• Mongolian spot
• nevus of Ota
• cellular blue nevus

10. Erythematous macules
An increased blood flow through the skin caused by capillary dilatation produces erythematous
macules.
These are easily blanched by pressure (positive diascopy) as in
• macular viral
• drug rashes
• psoriasis

11. PAPULE
A papule is an elevated solid lesion of the skin, less than 1 cm in diameter.
The features of a papule that need to be examined include the shape, color, umbilication,
distribution, configuration, and presence of tenderness.

12. Acuminate (pointed) Pityriasis rubra pilaris or follicular lichen planus
Erythematous and scaly Guttate psoriasis, secondary syphilis
Flat-topped, violaceous Lichen planus
Dome-shaped, pearly white, and umbilicated Molluscum contagiosum
Pedunculated Skin tags, neurofibromatosis
Coppery Secondary syphilis
Necrotic/haemorrhagic Pityriasis lichenoides, Papulonecrotic tuberculid
Yellowish Xanthelasma palpebrarum
Blue-black Melanoma, blue nevus, Kaposi’s sarcoma
Skin-colored Adenoma sebaceum , syringoma
Horny Keratosis pilaris
Verrucous Warts, seborrheic keratosis
ATTRIBUTES OF A PAPULE
SHAPE/COLOR/CONFIGURATION DISEASE

13. Lichen planus (flat top)
Neurofibromatosis
(pedunculated)
Warts (verrucous) Guttate psoriasis
(erythematous and scaly)
pityriasis rubra pilariasis (acuminate)
Molluscum contagiosum (pearly
white and umbilicated )

14. PLAQUE
A plaque is a solid plateau-like elevation of the skin surface
occupying a large surface area in comparison with its height
above the skin surface. Plaques are often formed by
coalescence of neighbouring papules or by enlargement of an
existing papule and they are more than 1 cm in size.
The prototypical plaque is the erythematous plaque of
psoriasis with silvery scales.
Annular plaques with flat to depressed center and raised
margins are characteristic of dermatophytic infections,
granuloma annulare, and certain other conditions.
The presence of atrophy, depigmentation, and follicular
plugging in erythematous plaques suggests a diagnosis of
chronic cutaneous lupus erythematosus.

15. • Annular scaly, flat to depressed center and raised
margins plaques seen in Tinea corporis and cruris

16. NODULE
A nodule is a palpable, solid, round, or ellipsoidal lesion greater than 0.5 cm in size. It is the depth of
the lesion that differentiates a nodule from a papule or plaque.
Nodule should be qualified by its:
• consistency (hard, firm, or soft)
• mobility (fixed or mobile)
• presence of tenderness
• surface changes (smooth, ulcerated, fungating, or keratotic).
Depending on the level of the skin involved, a nodule may involve primarily the epidermis, dermis,
or the subcutis.

17. Pure epidermal
nodules
• Nodular basal cell carcinoma
• keratoacanthoma.

18. Dermal nodules
• Metastatic carcinoma
• lymphomas
• histoid leprosy
• dermatofibroma

19. WHEAL
A wheal (hives) is an elevated lesion with erythema and edema
frequently with central pallor which characteristic feature of
urticaria.
Wheals result from a transient vascular reaction in the upper
dermis in which there is both vasodilation and increased
permeability of the capillaries giving rise to edema.
The borders are sharp but unstable and tend to change within
hours. Their shapes may vary too, from being round to oval,
geographic or annular. The size may range from a few millimeters
to more than 10 cm.
• Stroking of normal skin may produce wheals in individuals, this
phenomenon is known as dermographism.

20. ANGIOEDEMA
Its a diffuse, deep, edematous reaction occurring in areas with
loose dermis and subcutaneous tissue such as the lip, eyelids,
and rarely the larynx.
In contrast to wheals which are temporary, angioedema tends
to persist for a longer time and is often associated with dull
aching pain. Laryngeal edema may occur as a part of an
anaphylactic reaction to insect stings or drugs and may be fatal
because of airway obstruction.

21. VESICLE
A vesicle is a circumscribed,
elevated, superficial lesion
containing clear fluid, less than
0.5 cm in diameter.
• These leasions are typically
seen in
• Herpes simplex
• Insect bites
• Impetigo

22. BULLA
• A vesicle which is larger than 0.5 cm in
diameter is concidered is a bulla.

23. PUSTULE
A pustule is a like a vescicle, circumscribed, elevated
lesion containing visible purulent exudates. Pus is
composed of leukocytes and cellular debris and
often contains bacteria.
• sterile pus is a feature of many dermatoses such
as pustular psoriasis or subcorneal pustular
dermatosis.

24. CYST
A cyst is a sac that contains liquid or semisolid material, lined
by a true epithelium. It resembles a spherical nodule, but
palpation reveals a resilient feel. A cyst may be soft or doughy,
hard, or fluctuant.
The two most common cutaneous cysts are:
• Epidermal cysts (keratinous cysts)
(They are lined with squamous epithelium and produce
keratinous material)
• Pilar cysts
(They originate from the hair follicle and are lined with a multi-
layered epithelium that does not mature through a granular
layer)

25. ABSCESS
It’s a collection of pus below the dermis or subcutaneous
tissue. The pus in an abscess is not visible but can be
infered from the signs of inflammation in the overlying
skin and fluctuation.
• Abscess cavities do not have a well-defined lining as
cysts do.

26. PURPURA, PETECHIAE AND
ECCHYMOSES
Extravasation of red blood cells in the dermis produces pin-point
purpuric lesions which do not blanch (negative diascopy).
Smaller lesions (1–2 mm) are often called petechiae, whereas larger
and deeper lesions are called ecchymoses.
Purpuric lesions may be palpable or nonpalpable.
Such lesions may be seen in:
• Senile purpura,
• Henoch- Schonlein purpura
• thrombocytopenic purpura
• vasculitis
• port-wine stain
• purpuric variants of many conditions like pityriasis rosea.

27. SECONDARY LESIONS

28. CRUST
It’s a results from dried up exudates on
the skin surface. Crusts may at times
resemble scales especially when the
latter are thick and dark.
When blood forms a major component
of the crust, it is often referred to as a
scab.
• Crusts are usually secondary to some
preceding primary lesions such as
vesicles, bullae, or pustules.

29. EXCORIATIONS
Excoriations result from scratching and are characteristically linear. They are
commonly seen in pruritic disorders such as
• Atopic dermatitis
• Scabies
Lichenification is a plaque of thickened skin with accentuated skin markings
caused by constant rubbing, for example in the areas of lichen simplex
chronicus.

30. EROSION
An erosion results from the loss of a part or whole of the
epidermis but with an intact dermis or subepithelial tissue.
Erosions present as depressed moist lesions covered with
serous exudates. They may be circumscribed, linear, or
bizarre in shape. Healing occurs without scarring unless the
lesion becomes secondarily infected.
Common sources of erosions include traumatic detachment of
the epidermis and rupture of vesiculobullous lesions in
blistering disorders like:
• pemphigus
• toxic epidermal necrolysis
• epidermolysis bullosa
• infective lesions of herpes simplex

31. ULCER
An ulcer is a defect with a loss of epidermis and at least part of the dermis (upper
papillary dermis) and thus, ulcers always heal with scarring.
Examination of an ulcer should include the location, margins, edges, base, floor,
surrounding skin and tenderness.
Ulcer edges may be punched out, rolled, undermined, sloping, or jagged.
The floor may show the presence of pus, necrotic material, or healthy granulation tissue.
Palpation allows the evaluation of the structures forming its base and tenderness. Other
associated factors such as the presence of nodules, varicosities, the presence or absence
of adjacent pulse, sweating, and hair distribution may also be helpful in diagnosis.
Common causes of ulcers include:
• venous stasis
• trauma
• infections such as chancroid, tuberculosis, and pyoderma gangrenosum.

32. Type of edge description condition
Sloping Shallow ulcer usually covered with healthy
granulation tissue
Venous ulcer
Punched out Full-thickness loss of tissue from the edges Vasculitic/arterial ulcers, tertiary syphilis
undermined Destruction of subcutaneous tissue more
than the skin
Tuberculous ulcers, pressure sores
Everted/exophytic Growth of the tissue over and beyond the
edge
Squamous cell carcinoma
rolled Slowly growing edges with rolled-out
appearance
Basal cell epithelioma

33. Venous ulcer Arterial ulcer pressure sores
Squamous cell carcinoma (marjolin’s ulcer)

34. SCAR
A scar is a visible alteration in the
appearance of the skin following the
proliferation of fibrous tissue in response to
an injury, up to the level of the reticular
dermis. Hair follicles and other adnexal
structures are frequently destroyed within a
scar.
Initially, the scar is pink in color and later
becomes either
hypopigmented/hyperpigmented or may
have mottled appearance.
Scars may be:
• Atrophic
• Hypertrophic
• Keloidal

35. Multiple boxcar and pitted scars due to
acne
Keloid Hypertrophic scar

36. SCALE
Abnormal shedding or accumulation of the stratum
corneum in visible flakes is called scaling. Scales
are formed when there is either an excess
production or retention of the stratum corneum and
are primarily because of underlying parakeratosis.
When scaling over papules are the predominant
feature of a disease, the eruption is described as
papulosquamous.
Fine scales occurring in macular lesions of tinea
versicolor and erythrasma are described as
maculosquamous.

37. TYPES OF SCALES

38. Collarette scale
• Fine, peripherally attached, and centrally
detached scale at the edge of salmon-
colored patch/plaque
• Seen in Pityriasis rosea

39. FURFURACEOUS SCALE (BRANNY)
• Inconspicuous loose scales made visible by
scratching (scratch sign)
• Seen in Pityriasis versicolor

40. ICHTHYOSIFORM SCALE
• Large, polygonal fish-like scales
• Seen in Ichthyosis vulgaris

41. MICACEOUS SCALE
• Silvery-white scale
• Seen in psoriasis

42. LIMPET-LIKE
• Conical heaped up mound of adherent
scales
• Seen in Reiter’s syndrome

43. GREASY SCALE
• Moist, yellow-brown oily scaling on
seborrheic areas
• Seen in Seborrheic dermatitis

44. TRAILING SCALE
• Annular erythema with advancing
flat/elevated border and trailing scale at
the inner border with flattening and fading
of central area
• Seen in Erythema annulare centrifugum

45. MICA-LIKE/WAFER-LIKE SCALE
• Thin adherent mica-like scale attached at
the center of a lichenoid firm reddish-
brown papule and free at the periphery
• Seen in Pityriasis lichenoides chronica

46. DOUBLE-EDGED SCALE
• Annular or polycyclic, flat patch with an
incomplete advancing double edge of
peeling scale
• seen in Ichthyosis linearis circumflexa
(ILC), Netherton syndrome

47. CORNFLAKE SCALE
• Scale separates from lesions, leaving a
non-exudative red base
• seen in Pemphigus foliaceous, Flegel’s
disease

48. Hystrix-like scale
• Porcupine-like muddy brown or gray color
scaling over verrucous lesion
• Seen in Ichthyosis hystrix

49. COAT OF ARMOR
• Rigid, taut, yellow-brown adherent skin
covering the whole body
• Seen in Harlequin ichthyosis

50. LAMELLAR/PLATE-LIKE
SCALE (ARMOR PLATE)
• Large, polygonal, thick, rigid, dark brown
or grey firmly adherent scales
• Seen in Lamellar ichthyosis

51. SANDPAPER-LIKE SCALE
• Adherent, dry, rough, yellow, or brown
colored scales with a sandpaper-like
gritty feel
• Seen in Actinic keratosis

52. SPECIAL LESIONS

53. BURROW
• A burrow is a serpiginous tunnel within
the stratum corneum made by the scabies
mite. Burrows are “S” shaped, about 5
mm in length, and their presence in the
finger web spaces, wrist, or male genitalia
is diagnostic of scabies.
• Longer burrows (5–10 cm) on the feet
are seen in creeping eruption (larva
migrans) caused by the migration of
hookworm larvae.

54. COMEDONE
A comedone is a result of the dilatation and
plugging of hair follicle infundibulum with
keratin and lipids.
There are of two types:
• Open (blackheads)
visible as a black keratinous mass resulting
from the oxidation of the sebaceous contents
in a dilated follicular orifice.
• Closed (whiteheads)
The follicular openings are closed and the
lesions appear like tiny papules, lighter in color
than the surrounding skin.

55. MILIUM
Milia are small, superficial subepidermal
cysts. They occur on the face, especially in
the periorbital area.
• Sometimes they may arise on blistered
or damaged skin conditions like
dystrophic epidermolysis bullosa or
porphyria or in healed scars.

56. TELANGIECTASIA
They are distinctly visible dilated capillaries.
• They may be seen in
• rosacea,
• actinic and
• radiation damage, in
• dermatomyositis
• hereditary hemorrhagic telangiectasia.
Telangiectasias may be linear or matt-like.
• Poikiloderma is a combination of atrophy, telangiectasias,
and mottled pigmentation as seen in poikiloderma of Civatte.

57. CALCINOSIS
• Calcinosis occurs due to deposition of calcium
in the dermis or subcutaneous tissue and
presents itself as chalky white, hard papules,
plaques, or nodules.
• They can be
• Primary (due to underlying metabolic
abnormality)
• Secondary (occours at site of previous
inflammation or within cutaneous lesions like
epidermal cysts)

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