Classification of cutaneous lesions

The elemental lesions  are divided into:

  • Primary or primitive lesions are the initial consequences of an inflammatory skin disease;
  • Secondary lesions are progression of primary lesions.


Primary skin lesions

Among the primary skin lesions are:

The vesicles are small protrusions filled with clear fluid.
Vesicles can be the consequence of:

The maculae are small brown , red or white spots . The color depends on the amount of melanin.
Among the light spots are:

  • Anemic snows,
  • Vitiligo ,
  • Pitiríase alba.

Among the dark maculae are:

  • The freckles or ephelides,
  • The nevi .

lump is a solid skin formation:

  • Outgoing,
  • With a diameter greater than 1 cm,
  • That penetrates to the dermis and hypodermis.

The papule is a superficial protruding formation of less than 1 cm, caused by:

  • Thickening of the skin at the level of the epidermis,
  • Accumulation of inflammatory fluid in the dermis.

Most of the papules develop in clusters and also a rash occurs .
Some typical papules are those caused by:

The plate is a solid surface formation.
The papules that develop in groups can form a plaque.
Plaques are common in people with psoriasis.

The pustules are small lesions filled with pus.
They are usually the consequence of:


Primary skin lesions caused by allergic reactions

The rashes are lesions that cover small or large areas of skin.
They can be caused by an allergic reaction .
An  urticaria  is a skin reaction that occurs when someone comes in contact with a substance (food, plants, metals, etc.) that triggers an allergic-type reaction.

The typical cutaneous lesions of allergic reactions are:

The welts are skin lesions caused by an allergic reaction.
The welts are solid, reddish relief formations that cause intense itching. Typically disappear in a short time.
The welt is a typical urticaria lesion.

The erythema is an area of red or irritated skin. The erythematous lesions may have irregular borders and a variable extent.

Secondary skin lesions

  • The crust is the evolution of a skin lesion.
  • The abrasion is a skin itching caused by injury which may be caused by friction against a rough surface or a disease with itching, such as scabies.
  • The erosion is caused by loss of epidermal cells, may be the development of a vesicle or bubble bursting.
  • The cleft is a linear wound that can penetrate deeply into the dermis.
    If bleeding leaves scars, for example anal fissures .
  • The ulcer  is a tissue injury that can extend in depth and usually becomes chronic.
    For example, it is possible to see varicose ulcers caused by:

  • The scar is composed of fibrous connective tissue and is the result of the process of repairing an acute injury or an ulcer.


Causes of skin lesions

Skin lesions may be the consequence of various skin diseases.
These include:

Physical Injury Food / substance
allergy . Common allergens are:

  • Milk,
  • Eggs,
  • Pollen grains,
  • Grass, etc.

Skin diseases such as:

Skin lesions caused by AIDS
Skin lesions can be caused by diseases such as AIDS .
Acquired immunodeficiency syndrome or AIDS is caused by the Human Immunodeficiency Virus (HIV) that weakens the body’s immune system.
AIDS patients often develop lesions because the body is not able to resist or fight the virus.

Allergies and Allergic Reactions
Skin rashes occur mainly because of allergies to certain substances, chemicals, cosmetics, etc.
Sometimes they can occur because of medication overdose or administration of wrong medicines, for example, hydroxyurea (Oncocarbide ®) can cause redness and skin atrophy.

Cutaneous Leishmaniasis
The most frequent form of leishmaniasis causes one or more ulcers on the skin.
Initially, the lesion is a small red plaque whose size reaches up to 2 cm in diameter.
The lesion looks like a common insect bite.
After several weeks, the plaques become darker and form ulcers with:

  • Raised edges,
  • A central cavity.

The ulcer may be moist with exudate of pus or dried with a crust.
Wounds usually appear on exposed areas of the skin, especially:

  • A face,
  • The ends.

The lesions may occur immediately after the bite of an infected sandfly or may have an incubation period of weeks or months before causing the wounds.

Lyme disease
The Lyme disease is a bacterial infection caused by a spirochete: Borrelia burgdorferi.
It gets this disease with the tick bite .
Lyme disease causes a macula that can extend up to a half-meter.
For this reason it is also called migratory erythema.
The skin lesion is flat and is darker around the edge.

Behçet Syndrome
Skin problems are a common symptom of Behçet’s disease.
The skin manifestations of Behçet’s syndrome are different and red nodules often develop or pus-filled lumps (pustules) may form.
The lesions are:

  • Raised,
  • Red.

They can occur on any part of the body, but usually appear:

  • In the legs,
  • In the upper part of the trunk.

In some people, wounds or injuries can be seen when the skin is scratched or bitten.
Pustules resemble acne and can occur anywhere on the body.
This rash is sometimes called ” folliculitis .”

Unlike erythema nodosum caused by other diseases (which heal without scarring), the lesion of Behçet’s disease often becomes ulcerated.

Erythema nodosum: Red and painful nodules that usually occur in the legs and ankles, but sometimes also appear on the face, neck or limbs.

The syphilis primary is a sexually transmitted disease that causes the formation of a papule (sifiloma) in the genitals: women on the vulva, vagina or cervix. In men on the glans and foreskin.
Syphiloma develops into a cutaneous ulcer.

Dermatitis herpetiformis
This disease is part of the bullous lesions of the skin (such as pemphigus vulgaris).
Dermatitis herpetiformis is a rash with itching and blistering that occurs when the skin reacts to the antigluten antibodies that circulate in the blood.
It is also called celiac disease of the skin because it occurs along with celiac disease.
Although dermatitis herpetiformis can form anywhere in the body, the most common sites are:

  • The elbows,
  • Knees,
  • Buttocks,
  • Costas,
  • Back of neck.

In most cases (but not all), it is one of the most itchy skin diseases.

Symptoms of dermatitis herpetiformis
The symptoms of dermatitis herpetiformis come and go, for example:
1. Extremely itchy blisters or vesicles,
2. The rash has the same size and shape on both sides;
3. On the skin can manifest as an eczema.


  • The rash of pox begins at the trunk and spreads to the face and extremities.
  • The chicken pox causes the formation of red papules of 2 to 4 mm, with an irregular outline (rose petal). In general, the lesions are very numerous: 200-500.
  • Then a thin, clear-walled bladder develops over the reddish area.
    This skin lesion is very characteristic of chicken pox.
  • After about 8 to 12 hours, the bubble fluid becomes cloudy and the vesicle burst leaving a crust .
    The fluid is very contagious, but the scars are not considered contagious.
  • Usually, the crust falls after 7 days. Sometimes it leaves a scar that looks like a hole.
  • Although the lesion goes through this complete cycle in about 7 days, another milestone in the chicken pox is that new papules appear every day for about a week.
  • Children can not go back to school before all injuries have a crust on them.


About one third of people with diabetes develops a skin problem during their lifetime.
Some of these skin problems are unique to people with diabetes, but others occur because diabetics may have a predisposition for infections and circulation problems .

Skin diseases caused by diabetes include:

  • Infections (boils, calyx , folliculitis and nail infections)
  • Ringworm (athlete’s foot and ringworm often found in interdigital areas)
  • Necrobiose lipoídica
  • Eruptive Xantomatose
  • Disseminated granuloma
  • Vascular lesions in the lower limbs (eg diabetic foot )
  • Acantose nigricans.


Cutaneous Lupus Erythematosus
The lupus is a skin disease that can be:

  • Chronic (discoid),
  • Acute,
  • Subaguda.

The sun aggravates the skin problems of lupus.
All types of lupus cause skin problems, as listed below:

  • Ring lesions (circular spots with healthy skin in the center) on the face and head;
  • Scaly skin in disc-shaped areas;
  • Hair loss;
  • Smooth rashes on the face and body that resemble a burn ;
  • Cutaneous calcinosis;
  • Small black or red-purple spots on hands and feet;
  • Ulcers inside the mouth and nose;
  • Small red spots on the legs;
  • Raynaud’s Phenomenon ;
  • Palmar erythema.

Bites and stings: insects
Bats and mites often bite humans, but they are not poisonous. It is sometimes difficult to assess what kind of insect caused the bite or if the itching is caused by poison ivy or other skin diseases.
The most common symptoms are:
1. Small salient lesions
2. Pain or itching
3. Dermatitis (inflammation of the skin)
4. Allergies in hypersensitive people with blisters or swelling.

The impetigo is an infection of the upper layers of the skin and is most common in children 2-6 years.
Usually occurs when the bacteria enters a:

  • Cut,
  • Scratch,
  • Bug bite.

Impetigo is caused by the bacterium Staphylococcus, but can also be caused by Streptococcus (group A).
The initial symptoms are similar to red spines , surrounded by reddish skin.
In these lesions a clear fluid-filled gallbladder forms.
These injuries can occur anywhere on the body, but are usually found on the face, arms and legs.
The lesions are filled with pus and after a few days they burst, forming a thick crust. Itching is common.

If impetigo is caused by Streptococcus, the doctor prescribes antibiotics orally and antibiotic ointment to be used on the skin.


Skin lesions

Skin lesions in children

  • Children may have the same skin problems as adults. Newborns and children are at risk for diaper- related disorders .
  • Although many childhood skin problems disappear with age, children can inherit genetic and permanent skin diseases.
  • Young children have a more delicate skin and are more susceptible than adults to developing rashes or urticaria in response to food or environmental allergens.
    They are also more likely than adults to have a childhood disease (chicken pox or measles).
  • In most cases, childhood skin diseases are temporary and can be treated with:
    • Creams,
    • Warm baths,
    • Specific medications.

Among the most common skin diseases in children are:
1. Eczema (atopic dermatitis)
2. Baby rash
3. Seborrheic dermatitis  (seborrhea)
4. Chickenpox and measles
5. Warts
6. Acne
7. Rosella
8. Infectious erythema
9. Urticaria
10. Ringworm
11. Rash due to bacterial or fungal infections
12. Rash due to allergic reactions.


Cancerous and precancerous lesions

Precancerous lesions are skin changes of the skin that, over time, can become a skin cancer.
Among the precancerous lesions are:

Skin Cancer Injuries: Skin Cancer

A cancerous lesion may be the consequence of a primary cancer or metastasis to the skin.
A cancerous lesion may have the appearance of:

  • A cavity,
  • An open space on the surface of the skin,
  • A nodule,
  • A spot on the skin in the form of a map.

A malignant lesion may occur with:

  • Odor,
  • Flowing,
  • Bleeding,
  • Itching,
  • Pain.

In the case of breast cancer  ( carcinoma  breast ) , the skin lesions that can be formed are:

  • Papules
  • Subcutaneous nodules,
  • Vesicles,
  • Ulcers.

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