5. Top layer of skin
Function :
1. Protective barrier against bacteria and
germs
2. Makes new skin
3. Protects the body (langerhans cells)
4. Skin color (melanin)
Epidermis
6. Cell Types
● Keratinocytes
○ Predominant cell type, originate in basal layer
○ Produce keratin and responsible for formation of epidermal water barrier by
producing and secreting lipids
○ Regulates calcium absorption by activation of cholesterol precursors UVB light to
form vitamin D
● Melanocytes
○ Derived from neural crest cells and primarily produce melanin
○ Found between stratum basale and produce melanin
○ ‘Built in sunscreen’
● Langerhans cells
○ Dendritic antigen-presenting cells (APC)
○ Play a role in immune response
Epidermis
7. 1. Stratum basale (base layer)
a. A.k.a stratum germinativum, deepest layer that separated from the dermis layer
by basement membrane
b. Made up of cuboidal to columnar cells which are mitotically active stem cells that
continuously producing keratinocytes
2. Stratum spinosum (spiny layer)
a. 8-10 layers
b. Contains irregular, polyhedral cells with cytoplasmic processes, sometimes
called spines as it has spiny appearance
3. Stratum granulosum (granular layer)
a. Granules cell layer, 3-5 layers of cells
b. Contain keratohyalin and lamellar granules
i. Keratohyalin : contain keratin precursors that eventually aggregates, crosslink and
form bundle
ii. Lamellar granules : contain glycolipids that get secreted to the surface and function as
a glue to keep the cells stuck together
Epidermis - layers
8. 4. Stratum lucidum (clear layer)
a. Thin, clear layer of dead skin cells filled with keratin precursors called eleidin
b. Found in thick skin such as palms of the hands and soles of the feet
5. Stratum corneum (horny layer)
a. Made up of corneocytes : anucleated keratinocytes that have reached the final stage of
keratinocyte differentiation
b. First line of defense of body : form protective skin barrier against external environment
c. Also aids in hydration and water retention, prevents cracking of skin
d. Organize in brick (flattened keratinocytes filled with keratin and filaggrin) and mortar
(lipid mixture, surrounds the keratinocytes) formation within lipid-rich extracellular
matrix
Epidermis - layers
9.
10. 1. Acne (Acne is a condition from pilosebaceous gland, NOT EPIDERMIS CONDITION)
2. Boils (Boil is a condition from hair follicle, NOT EPIDERMIS CONDITION)
a. Pus filled bumps that develops in the skin, caused by staph infection
3. Dandruff
a. Seborrheic dermatitis : itchy red and greasy scales on skin with white or yellow
crusty or powdered flakes on scalp
4. Eczema
a. A.k.a atopic dermatitis : damages the skin barrier function causing the skin to
become more sensitive and prone to infection and dryness
5. Melanoma
a. Most dangerous skin tumor
Common conditions and disorders affect epidermis
12. 1. Fibrous connective tissue
2. Made up of 2 layers
a. Papillary dermis
i. Top layer of dermis, much thinner
than reticular dermis
ii. Consists of collagen fibers,
fibroblast cells, fat cells, blood
vessels, nerve fibers, touch
receptors and phagocytes
iii. Dermal papillae - fingerprints
b. Reticular dermis
i. Dense, irregular connective tissue
ii. Sebaceous gland, hair follicles,
sweat glands, stretch marks,
langers line
Dermis
13.
14. Function :
1. Support and protection
a. Consists of connective tissue framework for
strength, flexibility and protection of the
deeper anatomical structures
i. Strength : collagen type 1
ii. Elasticity : elastic fibre
2. Sensation
a. Nerve endings in the dermis allow to feel for
different sensation
3. Thermoregulation
a. Contains sweat glands
4. Skin moisture
a. Contains sebaceous gland secreting sebum
for hydration
Dermis
15. 1. Ehler-Danlos Syndrome
a. Defects in collagen that leads to weak collagen or not enough collagen in their
tissue
b. Can harm the connective tissue ability to support muscles, organs and other
tissue
c. Symptoms include hypermobile joints, unstable joints, soft skin that is thinner
and stretches more than normal, excessive bruising
Conditions related to dermis layer
16. 2. Hives (urticaria)
a. Raised red bumps or splotches on the
skin, happens during allergic
reaction
3. Hyperhidrosis
a. Overstimulation of eccrine sweat
glands
Conditions related to dermis layer
17. Fat layer which separates the dermis from the deeper
underlying structure (fascia and muscle)
Mostly adipocytes and connective tissue linked to fascia
below
Function :
1. Insulator
2. Protects the tissues and muscle underneath the
layer
3. Energy storage (adipocytes)
Hypodermis
18. 1. Erythema nodosum
a. Panniculitis; inflammation of subcutis
b. Presents with deep seated erythematous nodule, usually at skin
Conditions related to hypodermis layer
19. SKIN LESIONS
- PRIMARY MORPHOLOGY
- SECONDARY MORPHOLOGY
Morphology is the form or structure of an individual skin lesion
20. PRIMARY MORPHOLOGY
Abnormal skin conditions exists from birth or
acquired over a person’s lifetime also directly associated
with a specific cause.
21. Macule
- Flat, nonpalpable lesion usually at ,10mm in
diameter
- Examples; freckles,flat moles, rashes of
rickettsial infection,rubella, measles
Papules
- Elevated lesion usually <10 mm in diameter that
can be felt or palpated
- Examples; nevi, warts. Lichen planus, insect
btes, seborrheic keratoses
Plaques
- Palpable lesion >10 mm in diameter that are
elevated or depressed compared to the skin
surface
- Examples; psoriasis and granuloma annulare
22. Vesicle
- Small, clear fluid-filled blisters usually at <10mm
in diameter
- Examples; herpes infection, acute contact
dermatitis
Bullae
- Clear, fluid-filled blisters usually >10mm in
diameter
- Examples; burns, bites, irritant contact
dermatitis, allergic contact dermatitis
Pustule
- Vesicles contain pus
- Common in bacterial infections and folliculitis
and may rise in some inflammatory disorders
23. Nodule
- Raised lesion >10mm
- Rounded surface and caused by accumulation
of cells or change in connective tissue
Tumor
- Usually >5cm
- Solid, firm lesion that can be exophytic,
endophytic or level with sin surface
Cyst
- Sac-like nodule that usually has an epithelial
lining containing fluid or other debris
24.
25. SECONDARY MORPHOLOGY
Evolution from primary morphology; either due to
traumatic manipulation, such as scratching or rubbing,
or due to its treatment or progression
26. Erosion
- Loss part all of the epidermis
- Occurs after vesicle forms and the top peels
off
- Does no cause scar
- Occurs in impetigo, pemphigoid, herpes
simplex, burns and atopic dermatitis
Crust
- A collection of cellular debris, dried serum and
blood; scab
- Formed usually from vesicle, bullae or pustule
Ulcer
- A full thickness, focal loss of epidermis and
dermis;heals with scar
27. Fissure
- Vertical loss of epidermis and dermis with
sharply defined walls, cracks in skins
Excoriation
- Loss of epidermal integrity due to scratching
Scar
- A collection of new connective tissue
28. Lichenification
- Thickening of epidermis with accentuation of
normal skin
- Usually due to rubbing, scratching
- Can be seen in chronic eczema, lichen
simplex chronicus and atopic dermatitis
Erythema
- vasodilation or vessel inflammation
Petechiae, purpura, ecchymoses
- Bleeding in the skin from pinpoint to large
patches
- Petechiae <4mm
- Purpura 4-10mm
- Ecchymoses more than 1 cm
31. SHAPE AND CONFIGURATION OF RASH
Configuration is the shape of
single lesions and the arrangement
of clusters of lesions.
- Annular
- Arcuate
- Grouped
- Linear
-Polycyclic
- Reticular
- Scattered
- Serpiginous
- Targetoid
- Whorled
32. 1. Annular (ring shaped)
It's a complete ring shape.
Eg: tinea corporis, pityriasis rosea,
Sarcoidosis
Tinea corporis-circular
shape, erythematous, itchy
caused by fungal infection
Sarcoidosis - red tiny
bump usually located on
shins and ankle, may be
warm and tender to touch.
35. 6. Reticular (resemble netlike)
Livedo reticularis- due to
spasm of blood vessel or
blood flow near the skin
surface. Have mottled
appearance in net pattern.
Mostly shows on the leg.
36. 7. Serpiginous (snakelike) 8. Target lesion - target like / bull’s
eye
Cutaneous larva migrans also known
as migrant linear epidermidis, beach
worm.
erythema multiforme
37. 10. Whorled - stirred appearance,
rash configuration according to
Blaschko lines → thought to
represent pathways of epidermal cell
migration and proliferation during the
development of the fetus.
40. 1. Acral: involves the distal aspects of the head (ears, nose) and the
extremities (hands, fingers, feet, toes).
Chilblains (Perniosis)
41. 2. Dermatomal: involves an area of skin supplied
with sensory innervation by a particular nerve root,
do not cross the midline of the body.
Herpes zoster (Shingles)
43. 4. Lymphangitic: skin or subcutaneous
lesions appears along lymph channels of
leg or arm.
Cellulitis
44. 5. Photodistributed: follows the
sun-exposed skin. Typical areas of
involvement are the forehead, upper ears,
nose, cheeks, upper lip, neck, forearms,
and dorsum of the hands.
45. 6. Scattered: occurring across many
body locations can appear to be
distributed randomly or haphazardly.
-café au lait spot
46. 7. Symmetric: lesions symmetrically on
the extremities can be indicative of
diagnoses of many etiologies, including
infectious, metabolic, genetic, and
inflammatory causes.
Stasis dermatitis (u/l chronic venous
insufficiency)
47. 8. Widespread - involves the entire, or
almost the entire body
Exanthematous drug eruption
49. 1. Verrucous lesions
- have an irregular, pebbly, or
rough surface.
- Examples include warts and
seborrheic keratoses.
50. 2. Lichenification
- thickening of the skin with accentuation of
normal skin markings; it results from
repeated scratching or rubbing.
- Chronic atopic dermatitis
51. 3. Induration
- deep thickening of the skin, can result
from edema, inflammation, infiltration,
including by cancer.
- has a hard, resistant feeling.
- characteristic of panniculitis, some skin
infections, and cutaneous metastatic
cancers.
52. 4. Umbilicated lesions
- Has central indentation
- usually viral caused
- Examples: molluscum
contagiosum (poxvirus)
and herpes simplex.
53. 5. Xanthelasma: yellow-white plaques
on the upper medial eyelids in a patient
with hypercholesterolemia.
Xanthelasma are not specific for
familial hypercholesterolemia.
55. VEHICLE:
inactive creams, lotions, solutions and/or
ointments that change the properties of
medicine mixed into them — assisting its
application
56. Types Ointments
Eg: polyethylene glycol(water
soluble) or petrolatum (insoluble)
Creams (oil-in-water emulsions)
Eg: Aqueous cream
Lotions (powder+water)
Characteristics greasy preparations based Less greasy, drying effect light and
easily absorbed.
usually contain preservatives, such
as parabens (hydroxyben-zoates),
which can cause allergic contact
dermatitis
easily spread, slightly occlusive, least
potent vehicle
contain water or alcohol that
evaporates after application, giving a
cooling effect.
Areas to be
applied
USE in dry thick / hyperkeratotic
lesions
AVOID in hairy and intertriginous
areas (skin fold - axilla, groin)
USE for intertriginous areas (axilla,
groin)
USE for moist or exudative skin
lesions and hairy sites (e.g. the scalp).
Alcohol based-lotions should be
avoided on broken skin, as they sting.
Use Lubrication offer drying effect to help with wet or
damp skin lesions
provide drying effect from evaporation
57. Types Gel Foams (liquid film and gas bubbles)
Eg: emollient foam
Characteristics semi-solid preparations of high-molecular-weight
polymers.
Greaseless, translucent, easy to apply
poorly occlusive, do not provide hydration
May contain alcohol (drying quickly)
Cosmetically elegant
- Spread readily, easy to apply, leave little residue
More expensive
Areas to be
applied
treat acne or hair bearing area (e.g. scalp). USE for scalp or hair bearing area
Use USE for Acne, Exudative inflamm
(acute contact
dermatitis),
skin hydration and build up skin barrier
58. Types Pastes
e.g.Lassar's paste.
Solutions
Characteristic thick, adherent ointments containing a powder, Light and thin, easy to spread
Stinging d/t alcohol content
Use They are rarely used now due to poor cosmetic
acceptability. (Diaper rash, skin irritation)
Use for scalp (penetrate skin thru
hair)
60. Topical Corticosteroids
- Produce anti inflammatory
response in skin
- Effective for conditions of
hyperproliferation,
inflammation and
immunologic involvement
- Provide symptomatic relief
for burning and pruritic
lesions
Organised into
classes according to
strength (potency)
**Hydrocort 1% = 1 mg hydrocort in 1g
61. Topical Corticosteroid Selection
- Super high potency (Class I)
- Severe dermatoses over non facial & non intertriginous areas
- Apply on scalp, palms, soles, thick plaques on extensor surfaces
- Medium to high potency (Classes II to III)
- Mild to moderate non facial and non intertriginous areas
- On flexural surfaces for limited period
- Low potency (Class IV)
- Used for large areas and on thinner skin
- On face, eyelid, genital and intertriginous areas
63. Duration of treatment
- Super high potency: <3 weeks
- High and medium potency: <6-8 weeks
- Low potency: treat for 1-2 weeks intervals to avoid side effects (skin
atrophy, telangiectasia, steroid induced acne)
- Stop treatment when skin condition resolves → to avoid rebound /
flares
- Gradual taper potency and dosing frequency every 2 weeks
64. REFERENCES
1. American Academy of Dermatology Association: Basic dermatology of Curriculum -
Dermatology therapies
2. DermNet NZ - All about the skin https://dermnetnz.org
3. Msd manuals professional version - Description of skin lesions
https://www.msdmanuals.com/professional/dermatologic-disorders/approach-to-the-derma
tologic-patient/description-of-skin-lesions
4. LearnDerm - morphologic and configuration
https://www.visualdx.com/learnderm/morphologic-variation
66. Quiz 1
A 30 y/o gentleman came with a painful rashes
over the right chest
67. Question : Please describe the rash and give your
provisional diagnosis
68. Quiz 2
1. Describe the picture
2. Associated condition that
may be presented with this
morphology
The picture is an image of a
patient’s left forearm
69. Quiz 3
Type of vehicles that use for skin folds, less greasy
and easily absorbable, offers drying effects.
