The skin

Chapter One: The Skin
Md. Razwan Ahamed Shawan
Page1
Classification of cosmetics
Cosmetics can be defined as the following way:
1. According to their function
2. According to their uses
3. According to their physical nature.
According to function
a) Decorative function: e.g. lipstick, nailpolish
b) Corrective function: dry cream, heavy face powder
c) Protective function: dry cream, heavy face powder
d) Curative or therapeutic function: Antiperspirant and hair preparation.
According to their uses
a) For the skin; Powder, cream, lotion, make up etc.
b) For the hair: Shampoo, hair tonic, hair dressing, shaving preparation etc.
Cosmetology: Cosmetology is the science which deals with the formulation, manufacturing
and quality control of cosmetics product.
Cosmetics: Cosmetics are defined as substances that clean, beautify, promote attractiveness
or alter the appearance without affecting the body’s structure or function. This include skin
care products such as creams, lotions, powders, nail polish, face powder etc.
According to drug and cosmetics act, the cosmetics are defined as the materials or articles
which are intended to be rubbed, poured, sprinkled, sprayed, introduced in or otherwise for
cleansing, protecting, beautifying, promoting attractiveness or altering appearance.
Cosmeticals: Cosmeticals describe those products that are marketed as cosmetics but have
drug like effects.

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c) For the nails: nail polish, polish remover.
d) For teeth and mouth: Dentifrices and mouth washes.
e) Border line products: eye liner, eye shadow, muscara.
According to their physical nature
a) Aerosols: perfumes, after shave spray, hair spray etc.
b) Emulsion: cold cream
c) Gellies; hand jelly, hair jelly etc.
d) Mucilage: hand lotion, body lotion etc.
e) Oils: hair oils, body oils.
f) Cakes: compacts face powder
g) Paste: tooth paste, deodorant paste.
h) Powder: talcum powder
i) Soap: toilet soap
j) Solutions: after shave solution, astringent lotion etc.
k) Sticks: Lipsticks.
Properties of good cosmetics
A good cosmetics should have the following properties-
1. All the raw materials used should be of highest quality and they should be standardized
for the qualities.
2. All H2O used should be distilled or purified.
3. The perfumes used should be compatible with other ingredients of the preparation.
4. They should be tolerated all conditions particularly extreme of temperature and
humidity conditions to which they are likely to encountered in the market.
5. Should be economic.

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Skin
The human skin is the outer covering of the body. In human, it is the largest organ of the
integumentary system. The skin has up to seven layers of ectodermal system and guards the
underlying muscles, bones, ligaments and internal organs.
Because it interfaces with the environment, skin plays an important immunity role in protecting
the body against pathogenesis and excessive water loss. Its other functions are insulation,
temperature regulation, sensation, synthesis of vitamin D.
The integumentary system is the organ system that protects the body from various kinds of
damage, such as loss of water or abrasion from outside.

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Functions of the skin
Skin performs the following functions:
 Protection: an anatomical barrier from pathogens and damage between the internal
and external environment.
 Sensation: contains a variety of nerve endings that react to heat and cold, touch,
pressure, vibration, and tissue injury.
 Heat regulation: the skin contains a blood supply far greater than its requirements
which allows precise control of energy loss by radiation, convection and conduction.
 Control of evaporation: the skin provides a relatively dry and semi-impermeable
barrier to fluid loss.
 Aesthetics and communication: others see our skin and can assess our mood, physical
state and attractiveness.
 Storage and synthesis: acts as a storage center for lipids and water, as well as a means
of synthesis of vitamin D by action of UV on certain parts of the skin.
 Excretion: sweat contains urea, however its concentration is 1/130th that of urine,
hence excretion by sweating is at most a secondary function to temperature regulation.
 Water resistance: The skin acts as a water-resistant barrier so essential nutrients are
not washed out of the body.
The layers of skin
There are three main layers of the skin.
1. Epidermis: Epidermis is the top layer of the skin, the part of the skin we see.
The epidermis is the layer of skin in charge of:
 Making new skin cells: This happens at the bottom of the epidermis. The skin cells
travel up to the top layer and flake off, about a month after they form.

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 Giving skin its color: The epidermis makes melanin, which is what gives your skin color.
 Protecting your body: The epidermis has special cells that are part of your immune
system and help you stay healthy.
2. Dermis: Dermis is the second layer of skin. It's much thicker and does a lot for your
body.
 Making sweat: There are little pockets called sweat glands in the dermis. They make
sweat, which goes through little tubes and comes out of holes called pores.
 Helping you feel things: Nerve endings in the dermis help you feel things. They send
signals to your brain, so you know how something feels if it hurts.
 Growing hair: The dermis is where you'll find the root of each tiny little hair on your
skin.
 Making oil: Another type of little pocket, or gland, in your skin makes oil. The oil keeps
your skin soft, smooth and waterproof.
 Bringing blood to your skin: Blood feeds your skin and takes away bad stuff through
little tubes called blood vessels.
3. Subcutaneous fat: Subcutaneous fat is the bottom layer.
 Attaching the dermis to your muscles and bones: This layer has a special connecting
tissue that attaches the dermis to your muscles and bones.
 Helping the blood vessels and nerve cells: Blood vessels and nerve cells that start in
the dermis get bigger and go to the rest of your body from here.
 Controlling your body temperature: The subcutaneous fat is the layer that helps keep
your body from getting too warm or too cold.
 Storing your fat: This fat pads your muscles and bones and protects them from bumps
and falls.

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Layers of epidermis
1. Stratum basale/ Stratum germinativum: The stratum germinativum provides the
germinal cell necessary for the regeneration of the layers of epidermis. This germinal
cells are separated from the dermis by a thin layer of basement membrane. After a
mitotic cell division, a newly form cell will undergo a progressive maturation and
migrates to the surface. This process is known a keratinization.
2. Stratum spinosum: The cells that divide in the statum germinativum soon begin to
accumulate many desmosomes on their outer surface which provide a characteristic
prickles of the stratum spinosum which is often called the prickle- cell layer.
3. Stratum granulosum: The progressive maturation of keratinocytes is characterized by
the accumulation of keratin, called keratinization. The cells of the stratum granulosum
accumulate dense basoplilic keratophyllin granules. These granules contain lipids,
which along with the desmosomal connections, help to form a waterproof barrier that
functions to prevent fluid loss from the body.
4. Stratum lucidum: Epidermis varies in thickness throughout the body depending mainly
on frictional forces and the thickest on the palms of the hands and soles of the feet. It
is normally well seen in thick epidermis.
5. Stratum corneum: This is the outermost horny layer formed by the keratinised
stratified epithelial cells. The chief constituents of the stratum corneum are proteins,
lipids carbohydrates and an unidentified material of low molecular weight.

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Skin Diseases
The common skin disorders are-
1. Acne
2. Bed sores
3. Calluses & corns
4. Dry skin
5. Keratosis pilaris
6. Pityriasis Rosea
7. Psoriasis
8. Rosacea
9. Sebaceous cysts
10. Skin cancer
11. Impetigo
12. Scabies
13. Pediculosis
14. Ring worm
15. Eczema
16. Exfoliative dermatitis
17. Contact dermatitis
18. Urticaria
19. Leprosy.
Acne
Acne vulgaris, also known as acne, is a long-term skin disease that occurs when hair follicles
are clogged with dead skin cells and oil from the skin. Acne is characterized by areas of
blackheads, whiteheads, pimples, and greasy skin, and may result in scarring.
How does acne develop
The sebaceous gland produce sebum that normally travels via hair follicles to the skin surface.
However, skin cells can plug the follicles, blocking the sebum coming from the sebaceous
glands. When follicles become plugged skin bacteria called propionibacterium acnes begin to
grow inside the follicles, causing inflammation. Acne progress in the following manner-
1. Incomplete blockage of the hair follicle results in blackheads which is semisolid black plug.
2. Complete blockage of the hair follicle results in white heads which is semisolid white plug.
Normally infection and irritation causes the formation of whiteheads.
Eventually the plugged follicles bursts, spilling oil, skin cells and bacteria onto the skin surface.
In turn, the skin become irritated and pimples or lesions begin to develop. The basic acne
lesions is called a comedo.

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What causes acne?
 Rising hormone levels during puberty may cause acne. In addition acne is often
inherited.
Other causes of acne may include the following:
1. Hormone level changes during the menstrual cycle and puberty.
2. Certain drugs such as cortocosteroids, lithium and barbiturates.
3. Oil and grease from the scalp, mineral or cooking oil, certain cosmetics.
4. Propionibacterium acnes (P. acnes) is the anaerobic bacterium species inside the
pimples.
5. Acne can be aggravated by squeezing the pimples or by scrubbing the skin too hard.
Skin may also become irritated with frictions .
6. Some environmental conditions such as pollutions or humid conditions can also
irritated the skin and may cause acne.
Symptoms of acne
Acne can occur anywhere in the body. However acne most often appears in areas where there
is a high concentration of sebaceous glands including the following- face, chest, upper back,
shoulders, neck.
The following are the most common symptoms of acne. However each individual may
experience symptoms differently. Symptoms may include-
 blackheads
 whiteheads
 pass filled lesions that may be painful
 Nodules (solid, raised bumps).

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Treatment of acne
Generally specific treatment for acne will be determined by physician which should be based
on-
1. Age, overall health and medical history.
2. Severity of the acne
3. Patients tolerance for specific medications, procedure or therapies
4. Expectations for the course of the condition.
5. Patients opinion or preference.
Depending on the severity of acne, topical medication or systemic medications may be
prescribed. In some cases, a combination of both topical and systemic medications may be
recommended.
Medication
Topical medications to treat acne
Topical medication can be applied in the form of cream, gel lotion or solution. Examples
include:
1. Benzoyl peroxide: Kills the bacteria P. acne.
2. Antibiotics: Helps, stop or slow down the growth of . P. acnes and reduces inflammation.
3. Tretinoin: Stops the development of new acne lesions (comedones) and encourages cell
turnover, unplugging pimples.
4. Adapalene: Decreases comedo formation.
Systemic medications to treat acne
Systemic medications or oral antibiotics are ofter prescribed to treat moderate to severe acne
and may include the following.
 Doxycycline
 Erythromycin
 Tetracycline.

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Bed sores
Also called pressure sores or pressure ulcers — are injuries to skin and underlying tissue
resulting from prolonged pressure on the skin. Bedsores most often develop on skin that
covers bony areas of the body, such as the heels, ankles, hips.
How does a bedsores develop?
Pressure ulcers can develop when a large amount of pressure is applied to an area of skin over
a short period of time. They can also occur when less pressure is applied over a longer period
of time.
 The extra pressure disrupts the flow of blood through the skin.
 Without a blood supply, the affected skin becomes starved of oxygen and nutrients,
and begins to break down, leading to an ulcer forming.
 Pressure ulcers tend to affect people with health conditions that make it difficult to
move, especially those confined to lying in a bed or sitting for prolonged periods of
time.
Treatment of bed sores
Specific treatment of a bed sores is determined by the physicians based on severity of the
condition. Treatment may be more difficult once the skin is broken and may include the
following-
 Removing pressure on the affected area.
 Protecting the wounds with medicated gauze or other special dressings.
 Keeping the wound clean
 Transplanting healthy skin to the wound area.
 Medication i.g. antibiotics to treat infections.

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Corns
A corn is a small area of skin which has
become thickened due to pressure on it. A
corn is roughly round in shape. Corns press
into the deeper layers of skin and can be
painful.
Treatment of calluses and corns
Calluses are usually painless but corns can be
painful. Calluses can be avoided by removing
the source of the rubbing. Treatment for
corns may include-
Calluses
A callus is larger and broader than a corn and
has a less well-defined edge. These tend to
form on the underside of your foot (the sole).
They commonly form over the bony area just
underneath your toes.
 applying pads around the corn area
 Wearing larger more comfortable
shoes.
 Surgery.
Dry Skin
 Dry skin is an uncomfortable condition marked by scaling, itching, and cracking. It can
occur for a variety of reasons. You might have naturally dry skin.
 Dry skin can develop on any part of your body. It’s most likely to affect your hands,
arms, and legs.
 Exposure to dry weather conditions, hot water, winter and certain chemicals can cause
your skin to dry out.

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Treatment for dry skin
Treating dry skin may be as simple as keeping the moist by taking fewer baths and using
ointments or creams that keep the moisture in. Treatment may be also include-
1. Avoiding harsh soaps, detergents and perfumes which tend to dry the skin.
2. Avoiding rubbing or scratching the skin which can aggravates the symptoms and cause
infection.
3. Applying a salicylic acid solution or cream if the skin is scaly.
Keratosis Pilaris
 Keratosis pilaris (KP) is a common, autosomal dominant, genetic follicular condition
characterized by the appearance of rough, slightly red bumps on light skin and brown
bumps on darker skin.
 It most often appears on the back, outer sides of the upper arm, face, thighs, and
buttocks.
Treatment of keratosis pilaris
Usually no treatment is necessary for keratosis pilaris, since it normally clears up by itself.
Treatment may include-
1. Petrolium jelly with water, cold cream or salicylic acid (which removes the top layer of
the skin) to flatten the pimples.
2. A tretinoin cream which is chemically related to vitamin A.
[Tretinoin, also known as all-trans retinoic acid (ATRA)]
Pityriasis rosea
Pityriasis rosea is a skin rash. It is benign but may inflict substantial discomfort in certain cases.
Classically, it begins with a single "herald patch" lesion, followed in 1 or 2 weeks by a
generalized body rash lasting up to 12 weeks, however usually around 6 - 8.

Page13
Causes of Pityriasis rosea
The cause of pityriasis rosea is not certain, but its clinical presentation and immunologic
reactions suggest a viral infection as a cause. Some believe it to be a reactivation of herpes
viruses 6 and 7, which cause roseola in infants.
Diagnosis of pityriasis rosea
It is usually diagnosed based on medical history and physical examination. In addition the
physicians may order the following tests to help aid in the diagnosis-
1. Blood test
2. Skin biopsy- the removal of some of the discard skin for laboratory analysis. The sample
of skin is removed after a local anesthetic is administered.
Treatment of Pityriasis rosea
Specific treatment for pityriasis rosea will be determined by the physician based on-
1. Patient’s age, overall health and medical history
2. Extent of the rash
3. Patients tolerance for specific medications
4. Medicated lotion or creams(to sooth the itching)
5. Medication by mouth
6. Ultraviolet exposure under a physicians supervision.
Psoriasis
Psoriasis is a long-lasting autoimmune disease which is characterized by patches of abnormal
skin. These skin patches are typically red, itchy, and scaly. They may vary in severity from small
and localized to complete body coverage.

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Rosacea
Rosacea is a common rash, found on the central part of the face, usually of a middle-aged
person. A tendency to flush easily is followed by persistent redness on the cheeks, chin,
forehead and nose, and by crops of small inflamed red bumps and pus spots.
Symptoms of rosacea
Rosacea often begins with easy blushing and flushing of the facial skin. Eventually redness
will persist around the nose area extending to the rest of the face.
Rosaceae has a variety of clinical symptoms and is classified into the following four types-
Types:
1. Prerosacea: frequent episode of blushing and flushing of the face and neck.
2. Vascular rosacea: Swelling of blood vessels under the facial skin, leading to swollen,
warm skin.
3. Inflammatory rosacea: formation of pimples and enlarged blood vessels on the face.
4. Rhinophyma: enlarged oil glands in the nose and cheeks that cause an enlarged red
nose.
Treatment of Rosacea
Specific treatment for rosacae will be determined by the physician based on –
1. Patients health, age and medical history.
2. Extent of rash
3. Patients tolerance for specific medications, procedures or therapies.
4. Expectations for the course of the rash
5. Patients opinion or preference
The goal of treatment is to control the symptoms associated with rosacea.
1. Diet modifications such as- avoiding foods that dilate the skin’s blood vessels such as-
caffeine, spicy foods and alcohol.
2. Topical and oral
antibiotics
3. Glycolic acid pee
4. Cortisone cream
5. Electrosurgery.
6. Dermabrasion

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Impetigo
Impetigo is a bacterial infection that involves the superficial skin. t is typically due to either
Staphylococcus aureus or Streptococcus pyogenes. It is marked by yellow to red weeping and
crusted lesions especially around the nose and checks.
Treatment
Topical and systemic antibiotics are used. Topically applied mupirocin ointment or oral agents
such as dicloxacillin or cephalexin provide effective therapy.
Scabies
A contagious infestation of the skin with the itch mite, Sarcoptes scabiei. It typically presents
as an intensely pruritic rash & blisters & affects specific area of the body.
Treatment
 1% gamma benzene hexachloride lotion,
 0.25% benzyl benzoate lotion,
 5% permethrin cream is used.
Pediculosis
Pediculosis is an infestation of lice. The condition can occur in almost any species of warm-
blooded animal (i.e. mammals and birds), including humans. Although pediculosis in humans
may properly refer to lice infestation of any part of the body, the term is sometimes used
loosely to refer to pediculosis capitis, the infestation of the human head with the specific head
louse.
Treatment
 Lice infestations is modified by using various kinds of steroids and if infection occur
then antibiotic (systemic and topical) is used.

Page16
 Moreover manual removal of lice always is appropriate and strongly recommanded by
the National Pediculosis Association (NPA)
Ringworm
Dermatophytosis, also known as ringworm, is a fungal infection of the skin. Typically it results
in a red, itchy, circular rash. Hair loss may occur in the area affected. Symptoms begin four to
fourteen days after exposure. Multiple areas can be affected at a given time
Treatment of Ringworm
 Antifungal drug such as miconazole, clotrimazole are normally used.
 Griseofulvin or ketoconazole is given orally.
 Local treatment alone is of little benefit in ringworm of the scalp, nails and in most
cases of the feet.
 Topical preparation containing fungicidal agents are useful in the treatment of tinea
cruis (on hand) and tinea pedis (on the foot).
Eczema
Dermatitis, also known as eczema, is a group of diseases that results in inflammation of the
skin. These diseases are characterized by itchiness, red skin, and a rash. In cases of short
duration there may be small blisters while in long-term cases the skin may become thickened.
The area of skin involved can vary from small to the entire body.
Treatment
The goal for the treatment of eczema are to prevent itching, inflammation and worsening of
the condition. The treatment involves following parts-
 Keeping the skin well hydrated through the application of creams and ointments with
a low water and high oil contents.

Page17
 Corticosteroids cream are sometimes prescribed to decrease the inflammatory
reaction in the skin.
 If itching is severe, oral antihistamines may be prescribed.
 Phototherapy may also be used.
 Wash the place by KMnO4 lotion ¾ times a day.
Leprosy
Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria
Mycobacterium leprae or Mycobacterium lepromatosis.
In chronically infected persons, it may produce characteristics ring shaped, nodular or erosive
skin change specially on or near the face and sensory and motor dysfunctions of the hands and
feet.
Symptoms that develop include granulomas of the nerves, respiratory tract, skin, and eyes.
This may result in a lack of ability to feel pain and thus loss of parts of extremities due to
repeated injuries or infection due to unnoticed wounds. Weakness and poor eyesight may also
be present.
Treatment
 Tuberculoid leprosy is treated with multiple drug therapies such as daily oral dapsone
plus one dose of rifampin each month for 6 months.
 Daily dapsone and clofazimine plus monthly doses of rifampin for 24 months are
required to treat lepromatous laprosy.
[Dapsone, also known as diaminodiphenyl sulfone (DDS), is an antibiotic commonly used in
combination with rifampicin and clofazimine for the treatment of leprosy.]
 Tuberculoid leprosy is a skin condition characterized by solitary skin lesions that are
asymmetrically distributed.
 Lepromatous leprosy is a skin condition consisting of pale macules.

Page18
Skin Cancer
Skin cancers are cancers that arise from the skin. They are due to the development of abnormal
cells that have the ability to invade or spread to other parts of the body.
There are three main types of skin cancers: basal-cell skin cancer (BCC), squamous-cell skin
cancer (SCC) and melanoma.
Basal-cell carcinoma
Basal cell carcinoma (BCC)
(also known as basalioma or
basal cell cancer), is the most
common skin cancer. BCC
has a very low metastatic
risk, this tumor can cause
significant disfigurement by
invading surrounding tissues.
About two thirds of basal-cell
carcinomas occur on sun-
exposed areas of the body.
Squamous-cell carcinoma
Commonly presents as a red,
crusted, or scaly patch or
bump. Often a very rapid
growing tumor.
Squamous cell carcinoma, is
cancer that begins from
squamous cells, a type of skin
cell. It is one of the main
types of skin cancer. Cancers
that involve the anus, cervix,
head and neck, and vagina
are also most often
squamous cell cancers.
Malignant melanoma
Melanoma, also known as
malignant melanoma, is a
type of cancer that develops
from the pigment-containing
cells known as melanocytes.
Melanomas typically occur in
the skin but may rarely occur
in the mouth, intestines, or
eye. In women they most
commonly occur on the legs,
while in men they are most
common on the back.

Page19
Prevention of skin cancer
Do Not Burn or Tan
 Avoid intentional tanning.
 Avoid tanning beds.
Ultraviolet light from the sun and tanning beds causes skin cancer and wrinkling.
Seek Shade
 When sun’s rays are the strongest between 10 a.m. and 4 p.m.
Wear Protective Clothing
 Long-sleeved shirt and pants.
 A wide-brimmed hat and sunglasses.
Generously Apply Sunscreen
 Use a broad spectrum sunscreen with Sun Protection Factor (SPF) 30 or higher for
protection from ultraviolet A (UVA) and ultraviolet B (UVB) radiation.
 Apply 15 minutes before going outdoors and reapply every two hours.
 Apply 1 ounce (2 tablespoons) of sunscreen to your entire body 30 minutes before
going outside. Reapply every two hours or immediately after swimming or excessive
sweating.
Use Extra Caution Near Water, Snow, and Sand
 These surfaces reflect the damaging rays of the sun, which can increase your chance of
sunburn.
Get Vitamin D Safely
 Through a healthy diet.
 Take vitamin supplements.

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