Skin cancer

Skin cancer is a group of malignant skin tumours that develop when skin cells begin to divide uncontrollably and form a tumour. It is not one specific tumour and does not refer only to melanoma. The most common types of skin cancer are basal cell carcinoma, also known as basalioma, squamous cell carcinoma and melanoma. Less common malignant skin tumours include Merkel cell carcinoma, cutaneous lymphomas, Kaposi sarcoma and other tumours.

Skin cancer can have many different appearances. It may resemble a mole, but in other cases it can appear as a pale, pink, skin-coloured, rough, scaly, bleeding or non-healing skin lesion. It is therefore important to recognise not only the signs of melanoma but also the possible manifestations of non-melanoma skin cancer, particularly basal cell carcinoma and squamous cell carcinoma.

Skin cancer is often associated with prolonged or intense exposure to ultraviolet radiation. The main sources of UV radiation are sunlight and artificial UV sources such as sunbeds. The risk is higher in people with fair skin, frequent sunburn, numerous moles, a weakened immune system, a family history of skin cancer or a previous skin cancer diagnosis. However, skin cancer can also develop in people without obvious risk factors and on skin that previously appeared completely normal.

The positive aspect is that some skin cancers can be detected early because they develop on the surface of the skin and may be visible. Early diagnosis substantially improves treatment options, reduces the risk of tissue damage and, in melanoma, can be decisive for the prognosis.

What is skin cancer?

Skin cancer is a malignant tumour that develops from different types of skin cells. The skin consists of several layers and multiple cell types. The type of skin cancer that develops depends on which cells become malignant.

Basal cell carcinoma develops from basal cells located in the deepest part of the outer layer of the skin, known as the epidermis. Squamous cell carcinoma develops from squamous cells that form the upper layers of the epidermis. Melanoma develops from melanocytes, the pigment-producing cells that create melanin and give colour to the skin, hair and moles. Merkel cell carcinoma is a rare and aggressive form of skin cancer whose tumour cells display neuroendocrine characteristics.

Skin cancer is not always melanoma. In fact, most skin cancers belong to the non-melanoma skin cancer group. This group most commonly includes basal cell carcinoma and squamous cell carcinoma. Melanoma is less common but is generally more dangerous because, when not detected early, it has a greater risk of spreading to the lymph nodes and other organs.

Types of skin cancer

Understanding the different types of skin cancer is important because they vary in appearance, growth rate, risk of spreading and treatment approach. This article provides an overview, while detailed information about each diagnosis is available in separate Medart encyclopaedia articles.

Basal cell carcinoma or basalioma

Basal cell carcinoma is the most common type of skin cancer. It usually grows slowly and most often develops on sun-exposed areas such as the face, nose, forehead, ears, neck or scalp. It may appear as a non-healing ulcer, a pearly or shiny nodule, a pink patch, a repeatedly bleeding skin lesion or a scab that does not disappear.

Basal cell carcinoma usually has a low risk of metastasis, but it is nevertheless a malignant tumour. If left untreated, it can locally damage the skin, cartilage, bone and surrounding tissues, particularly when located on the nose, ears, eyelids or other anatomically complex areas.

Squamous cell carcinoma

Squamous cell carcinoma is a skin cancer that develops from squamous skin cells. It frequently develops on sun-damaged skin but can also arise in chronic wounds, scars or areas of persistent inflammation. It may appear as a rough, scaly, thickened or painful lesion, an ulcer, a crust or a bleeding area of skin.

Squamous cell carcinoma has a greater risk of spreading than basal cell carcinoma, particularly when the tumour is located on the lips, ears, scars or chronic wounds, or when the person has a weakened immune system. Suspicious rough, scaly or bleeding skin lesions should therefore be assessed without unnecessary delay.

Melanoma

Melanoma is a skin cancer that develops from pigment-producing cells known as melanocytes. It may arise from an existing mole but can also appear as a new lesion on previously normal skin. Melanoma is often associated with a dark or multicoloured mole, although it is not always black. Some melanomas may be pink, red or pale.

Melanoma is less common than basal cell carcinoma and squamous cell carcinoma, but it is particularly important because it has a greater risk of spreading if it is not detected early. Suspicious signs include asymmetry, irregular borders, multiple colours, enlargement and any change over time.

Actinic keratosis

Actinic keratosis is not yet an invasive skin cancer, but it is a precancerous change caused by sun damage that may, in some cases, progress to squamous cell carcinoma. It usually appears as a rough, scaly, dry, pink or brownish patch on sun-exposed skin, including the face, forehead, nose, ears, scalp, hands or forearms.

Actinic keratosis is important because some lesions may develop into squamous cell carcinoma. It should not be regarded merely as “dry skin” or a cosmetic concern. A rough patch that does not disappear, repeatedly returns or becomes tender should be examined by a dermatologist.

Merkel cell carcinoma

Merkel cell carcinoma is a rare but aggressive form of skin cancer. It may appear as a rapidly growing, usually painless pink, red, bluish or purple nodule. It occurs more commonly in older adults, on sun-damaged skin and in people with a weakened immune system.

Although Merkel cell carcinoma is much less common than melanoma, basal cell carcinoma or squamous cell carcinoma, it is medically important because it can grow and spread rapidly. Such a lesion requires prompt medical assessment.

Non-melanoma skin cancer

Non-melanoma skin cancer is a general term for skin cancers other than melanoma. It most commonly refers to basal cell carcinoma and squamous cell carcinoma. These tumours generally develop from keratinocytes, the main cells of the epidermis, and are therefore also known as keratinocyte carcinomas.

Basal cell carcinoma and squamous cell carcinoma most frequently develop on sun-exposed areas such as the face, nose, ears, lips, scalp, neck, hands and forearms. However, they may also occur elsewhere. Basal cell carcinoma generally grows slowly and rarely metastasises, but it can cause substantial local tissue damage if left untreated. Squamous cell carcinoma can be more aggressive and may, in some cases, spread to the lymph nodes or other organs.

How skin cancer develops

Skin cancer is not an infection. It cannot be transmitted from one person to another through touching the skin, sharing towels, swimming in a pool or ordinary everyday contact. It is therefore more accurate to refer to the mechanism of skin cancer development rather than a mechanism of infection.

Skin cancer develops when damage accumulates in the genetic material, or DNA, of skin cells. DNA acts as the cell’s instruction system, determining when the cell should divide, stop dividing and die. If DNA damage affects the mechanisms controlling cell growth, cells may begin to divide uncontrollably. Over time, these cells can form a malignant tumour.

Ultraviolet radiation is one of the most important causes of DNA damage. UV radiation can directly damage cellular DNA and promote the accumulation of mutations. The body has DNA-repair mechanisms and immune surveillance that help identify and eliminate damaged cells. However, when damage is extensive, repeated over many years or accompanied by a weakened immune system, the risk of a malignant tumour increases.

Genetic predisposition, skin type, previous sunburn, chronic wounds, scars, exposure to certain chemicals, immunosuppression and a previous skin cancer diagnosis may also contribute to the development of skin cancer. In melanoma, the number of moles and the presence of atypical moles are also relevant.

Timeline of skin cancer development

Skin cancer does not usually develop within a single day. In most cases, it is a long-term process in which cellular damage accumulates gradually. The patient usually notices only the visible stage, such as a new lesion, a changing mole, a non-healing wound or a bleeding area of skin.

Repeated UV exposure or other risk factors

DNA damage develops in skin cells. The skin may still look normal, or signs of sun damage such as pigmentation, wrinkles and roughness may appear.

Accumulation of cellular damage

Some damaged cells are repaired or destroyed, while others retain mutations. Actinic keratosis, new skin patches or changing lesions may appear.

Precancerous changes

Cells become atypical, but invasive cancer has not yet developed. A person may notice a persistent rough or scaly patch, particularly on the face, ears, scalp or hands.

Early skin cancer

A malignant tumour develops within the superficial layers of the skin. It may appear as a non-healing ulcer, pearly nodule, pink patch, changing mole, bleeding lesion or persistent crust.

Advanced skin cancer

The tumour may grow deeper, damage surrounding tissues or spread. The lesion may enlarge, become painful, bleed, ulcerate or thicken, and enlarged lymph nodes may appear.

Symptoms and early signs of skin cancer

Skin cancer symptoms are not identical in every patient. Different tumours may have different appearances, and the lesion may initially seem insignificant. It is particularly important to notice changes over time: a lesion may grow, change colour, bleed, fail to heal, itch, become painful or look different from a person’s other skin lesions.

A dermatologist should assess the skin if any of the following signs are present:

• a new skin lesion that enlarges or changes;
• a mole that changes its shape, colour, size or borders;
• a non-healing wound or ulcer;
• a scab that repeatedly forms in the same location;
• a skin lesion that bleeds without an obvious injury;
• a rough, scaly or thickened patch;
• a pink, red, skin-coloured, pearly or dark nodule;
• a lesion that itches, hurts, tingles or becomes tender;
• a patch that resembles a scar but gradually enlarges;
• a dark line beneath a nail or a changing pigmented area on the sole, palm or mucous membrane.

Main signs that may indicate skin cancer

For practical purposes, it is helpful to remember several signs that should not be observed at home for a prolonged period without medical assessment.

A non-healing wound or ulcer

Basal cell carcinoma and squamous cell carcinoma may present as a skin lesion that does not heal or repeatedly forms a crust.

A lesion that bleeds or is easily injured

Repeated bleeding without a clear cause may indicate a malignant or precancerous process.

A changing mole

Changes in size, shape, colour, borders or sensation are important warning signs of melanoma.

A rough, scaly or painful patch

This may be a sign of actinic keratosis or squamous cell carcinoma, particularly on sun-exposed skin.

A lesion that looks different from the others

The “ugly duckling” principle helps identify a lesion that does not match the usual pattern of a person’s moles or skin lesions.

Can skin cancer hurt, itch or bleed?

Skin cancer may be painless and cause no symptoms at first. This is one reason why people sometimes delay seeing a doctor. However, skin cancer may also itch, tingle, become tender or painful, bleed or repeatedly form a crust. The absence of symptoms does not mean that a lesion is safe, and pain alone does not mean that it is cancer. The appearance of the lesion, changes over time and medical assessment are the most important factors.

Is skin cancer always dark?

No. Melanoma may often be dark or multicoloured, but this is not always the case. Some melanomas are pink, red or pale. Basal cell carcinoma and squamous cell carcinoma are often not dark and may appear pink, skin-coloured, pearly, scaly, ulcerated or similar to a non-healing wound. Skin cancer should therefore not be associated only with a black mole.

Where does skin cancer most commonly develop?

Skin cancer develops more commonly on areas that have received substantial UV exposure over a lifetime. Typical locations include the face, nose, ears, lips, forehead, scalp, neck, shoulders, back, chest, hands, forearms and lower legs.

However, skin cancer can also occur in areas that receive little sunlight. Melanoma may develop on the soles, palms, beneath the nails, on mucous membranes or in other less visible locations. A skin self-examination should therefore include not only the face and hands, but also the back, scalp, feet, spaces between the toes, nails and skin folds.

Moles and melanoma

Melanoma may develop from an existing mole, but it can also arise as a completely new lesion on previously normal skin. It is therefore important to monitor not only existing moles but also new pigmented or unusual lesions.

The ABCDE principle is widely used when assessing moles:

• A — asymmetry. One half of the lesion does not resemble the other.
• B — border. The borders are irregular, jagged, blurred or uneven.
• C — colour. The lesion contains several colours, such as brown, black, red, grey, blue or white.
• D — diameter. The lesion is enlarging or is larger than the person’s other moles.
• E — evolution. The lesion changes over time, grows, changes colour, bleeds, itches, becomes painful or otherwise appears different.

Another practical principle is the “ugly duckling” sign. It means that attention should be paid to a lesion that looks different from a person’s other moles. If most moles are similar but one is noticeably darker, larger, more irregular or otherwise different, it should be examined by a dermatologist.

Detailed information about melanoma signs is available in the article “Melanoma”. Practical information about mole assessment is available in “Mole examination”. Information about examination using a specialised optical instrument is available in “Dermoscopy”.

Who has a higher risk of developing skin cancer?

The risk of skin cancer increases when a person is repeatedly or chronically exposed to UV radiation and when the body has a reduced ability to repair or eliminate damaged cells. Risk is not the same for everyone but may be increased in the following situations:

• fair skin, fair or red hair and light-coloured eyes;
• skin that burns easily and tans poorly;
• frequent or severe sunburn, particularly during childhood or adolescence;
• long-term outdoor work or hobbies;
• sunbed use;
• numerous moles or atypical moles;
• melanoma or another skin cancer in the family;
• a previous skin cancer diagnosis;
• a weakened immune system, for example after organ transplantation or because of certain illnesses or treatments;
• chronic wounds, scars, persistent inflammation or previously irradiated skin;
• older age, because UV-related damage accumulates over a lifetime.

Fair skin increases the risk because it contains less melanin, a pigment that provides partial protection from UV radiation. However, skin cancer can also occur in people with darker skin and may be diagnosed later if it is not recognised promptly.

Can skin cancer be hereditary?

Most cases of skin cancer are not directly inherited in a simple manner. However, risk-related characteristics may run in families, including skin type, the number of moles, a tendency to develop atypical moles or certain genetic mutations. If a first-degree relative has had melanoma or several family members have had skin cancer, individual risk should be discussed with a dermatologist.

Can the body develop immunity to skin cancer?

The body does not develop immunity to skin cancer in the way it may develop protection against certain infections following illness or vaccination. A person cannot “recover from” skin cancer and become protected from developing it in the future. On the contrary, a person who has previously had skin cancer may have an increased lifetime risk of developing another skin cancer.

The immune system nevertheless plays an important role in tumour surveillance. A healthy immune system can recognise and destroy some damaged or atypical cells. When the immune system is suppressed, for example after organ transplantation or because of certain treatments, the risk of squamous cell carcinoma and other skin tumours may be increased. Modern oncology also uses the immune system’s ability to recognise cancer cells: in some advanced skin cancers, a doctor may prescribe an immunotherapy-type treatment.

When should you see a dermatologist?

You should consult a dermatologist if a skin lesion is new, changing, non-healing, bleeding, itchy, painful, rapidly growing or looks different from other lesions. Medical assessment should not be delayed if the lesion is located on the face, nose, ears, lips, scalp, genital area, sole or beneath a nail, or if the patient has previously had skin cancer.

A medical consultation is also advisable for people with numerous or atypical moles, a family history of melanoma, repeated sunburn or regular sunbed exposure. In higher-risk patients, the dermatologist may recommend regular preventive skin examinations.

How is skin cancer diagnosed?

The diagnosis of skin cancer begins with a dermatological examination. The doctor assesses the lesion’s appearance, location, size, colour, borders, surface, symptoms and changes over time. Information about previous sunburn, sunbed use, family history, previous skin tumours and immune status is also important.

Dermoscopy is the examination of a skin lesion using a specialised instrument known as a dermatoscope. It allows the doctor to assess structures under magnification that cannot be seen with the naked eye. Dermoscopy helps distinguish benign lesions from suspicious ones, but a final cancer diagnosis is usually confirmed by histological examination.

If a lesion is suspicious, the doctor may recommend a biopsy or surgical removal. A biopsy involves taking a tissue sample for laboratory analysis. Histological examination means examining the tissue under a microscope to determine whether malignant cells are present, identify the tumour type and assess other features important for treatment.

Not every skin lesion needs to be removed. Some benign lesions can be monitored, while others may be removed for cosmetic or mechanical reasons. Suspicious lesions, however, must be examined using a medically appropriate method. If melanoma is suspected, the removal method must be selected particularly carefully so that accurate histological assessment is not compromised.

Can a dermatologist immediately tell whether a lesion is cancerous?

An experienced dermatologist can often assess whether a lesion appears benign, suspicious or highly suspicious. However, the final diagnosis frequently depends on histology. This means that the doctor may have a well-founded clinical suspicion of skin cancer, but laboratory examination of the tissue is required for confirmation.

How often should moles be examined?

There is no single universal examination interval suitable for everyone. The frequency of checks is determined according to individual risk. People with numerous moles, atypical moles, a family history of melanoma, previous skin cancer, fair skin, immunosuppression or significant UV exposure may be advised by a dermatologist to attend regular examinations at defined intervals.

Regardless of the scheduled preventive examination, medical advice should be sought sooner if a new, changing, bleeding, rapidly growing or non-healing lesion appears.

Skin cancer treatment

Skin cancer treatment depends on the tumour type, size, depth, location, histological characteristics, the patient’s age and general health, and whether the tumour is localised or has spread. The treatment plan is determined by a doctor, often in cooperation with a dermatologist, surgeon, oncologist or other specialists.

Main treatment approaches may include:

• surgical excision of the tumour with appropriate safety margins;
• Mohs micrographic surgery in selected locations or high-risk cases when available and medically appropriate;
• cryotherapy for certain superficial lesions or precancerous changes;
• local treatment using prescription medicines prescribed by a doctor in selected cases;
• photodynamic therapy for certain superficial skin changes;
• radiotherapy when surgery is unsuitable or additional treatment is required;
• systemic treatment, such as immunotherapy-type or targeted therapy in selected advanced cases;
• involvement of an oncologist in melanoma, high-risk squamous cell carcinoma, Merkel cell carcinoma or suspected metastatic disease.

Specific prescription medicines are not listed in this article because treatment selection is individual and must be determined by a doctor after assessing the diagnosis, histology, stage and the patient’s overall health.

Can skin cancer be cured?

Many skin cancers detected at an early stage can be treated successfully. The prognosis for basal cell carcinoma is generally favourable when it is diagnosed and treated promptly, although an untreated tumour may cause substantial damage to surrounding tissues. The prognosis for squamous cell carcinoma depends on the tumour’s size, depth, location and risk features. The prognosis for melanoma largely depends on how deeply the tumour has grown into the skin and whether it has spread.

The earlier skin cancer is detected, the greater the possibility of treating it with a smaller intervention and achieving a better outcome. A person should not wait until a lesion becomes large, painful or obviously dangerous.

Does skin cancer treatment always require surgery?

Surgery is a very common and effective treatment for skin cancer, but it is not always the only option. In selected cases, particularly for superficial lesions or precancerous changes, the doctor may choose another method. However, when invasive skin cancer or melanoma is suspected, histological assessment of the tissue is essential, and the treatment method must be selected so that diagnostic accuracy and patient safety are not compromised.

Can skin cancer be treated with lasers or creams?

Certain superficial skin changes and precancerous lesions can sometimes be treated using local methods, including prescription medicines or procedures selected by a doctor. However, lasers and creams are not universal treatments for skin cancer. Attempting to burn, dissolve or remove a suspicious lesion without medical supervision can delay diagnosis and interfere with histological examination.

Will there be a scar after skin cancer removal?

A scar usually remains after surgical removal of a skin lesion because the skin is cut and must heal. The size and appearance of the scar depend on the lesion’s size and location, the selected method, individual healing characteristics and postoperative care. The doctor’s aim is to treat the tumour fully while preserving function and achieving the best possible cosmetic result, particularly on the face and other visible areas.

Can skin cancer return after removal?

Yes. Skin cancer can recur, particularly if the tumour was high-risk, located in an anatomically difficult area or could not be removed completely. In addition, a person who has previously had skin cancer may have an increased risk of developing a new skin cancer elsewhere. Follow-up appointments and regular skin self-examination are therefore important after treatment.

How dangerous is skin cancer?

The degree of risk varies substantially between different types of skin cancer. Basal cell carcinoma usually grows slowly and rarely spreads but can cause significant local tissue damage. Squamous cell carcinoma can be more aggressive and may metastasise in certain cases. Melanoma is particularly dangerous when diagnosed late because it can spread to the lymph nodes and other organs. Merkel cell carcinoma is rare but is an aggressive form of skin cancer.

Skin cancer can be fatal, particularly in late-stage melanoma, advanced squamous cell carcinoma or Merkel cell carcinoma. However, skin cancer detected at an early stage can often be treated successfully. Early recognition, accurate diagnosis and timely treatment are therefore essential.

What happens if skin cancer is not treated?

Untreated skin cancer may continue to grow. Basal cell carcinoma may invade more deeply and damage surrounding tissues, particularly on the nose, ears, eyelids and other anatomically complex areas. Squamous cell carcinoma may enlarge, ulcerate, become painful and, in some cases, spread to the lymph nodes. Untreated melanoma may spread through the body and become life-threatening. A suspicious lesion should therefore not be observed for a prolonged period without medical assessment.

How can the risk of skin cancer be reduced?

The risk of skin cancer cannot be reduced to zero, but it can be substantially lowered by limiting UV-related skin damage and arranging prompt assessment of suspicious lesions.

Main preventive measures include:

• avoiding prolonged exposure to direct sunlight, particularly when UV radiation is most intense;
• seeking shade, especially during summer and when travelling to sunny countries;
• wearing clothing that covers the skin, a wide-brimmed hat and sunglasses;
• using a broad-spectrum sunscreen with an appropriate SPF;
• applying sufficient sunscreen and reapplying it after swimming, sweating or towel drying;
• avoiding sunbeds;
• protecting children’s skin from sunburn;
• regularly examining the skin at home;
• attending preventive dermatological examinations when individual risk is increased.

Which SPF should be used to help prevent skin cancer?

A sunscreen should provide broad-spectrum protection, meaning protection against both UVA and UVB radiation. A sufficiently high SPF should be used in daily life and particularly during summer. For people with a high risk, fair skin, previous skin tumours or intense sun exposure, a doctor may recommend SPF 50+ protection. Sunscreen should not be treated as permission to remain in the sun longer but as one part of combined protection that also includes shade, protective clothing and limiting excessive UV exposure.

Should SPF be used on cloudy days?

Yes. UV radiation can reach the skin even when the weather is cloudy. Clouds reduce visible sunlight but do not always reduce UV exposure sufficiently. Sun protection remains important during prolonged outdoor activity, particularly in spring and summer, even when the sun is not directly visible.

Are sunbeds safe if used only occasionally?

Sunbeds are not a safe way to achieve a “healthy tan” and do not prevent skin cancer. Artificial UV radiation damages the DNA of skin cells and increases the risk of skin cancer. Even occasional sunbed use cannot be considered safe, particularly for people with fair skin, numerous moles, a family history of melanoma or previous sunburn.

How should a skin self-examination be performed?

Skin self-examination helps identify new or changing lesions. It should be performed in good lighting, using a mirror or asking another person to help examine areas that are difficult to see.

During a self-examination, check:

• the face, nose, lips and ears;
• the scalp;
• the neck, shoulders and chest;
• the arms, palms, spaces between the fingers and nails;
• the back and buttocks;
• the abdomen and sides of the body;
• the legs, lower legs, feet, heels and soles;
• skin folds and the genital area if unusual lesions or symptoms are present.

It is particularly important to monitor changes over time. A suspicious lesion may be photographed under similar conditions for comparison, but a photograph does not replace a medical examination.

Do children also need sun protection?

Yes. Children’s skin is sensitive to sunburn, and sunburn during childhood may increase the risk of skin cancer later in life. Shade, appropriate clothing, a hat, sunglasses and age-appropriate sunscreen are important for children. Babies and young children should be protected particularly carefully from direct sunlight.

Can a person still spend time in the sun after a skin cancer diagnosis?

Protection from UV radiation becomes especially important after a skin cancer diagnosis. This does not mean that a person cannot go outdoors, but deliberate tanning, sunbeds and sunburn should be avoided. A doctor can provide individual recommendations based on the type of skin cancer, treatment and future risk.

What is currently well established in medicine?

It is well established that UV radiation from the sun and sunbeds is an important risk factor for skin cancer. The importance of early diagnosis is also strongly supported: the earlier a suspicious lesion is assessed and treated, the better the treatment options usually are.

Dermoscopy is an important dermatological diagnostic method that helps assess skin lesions more accurately. Histological examination remains the main method for confirming a diagnosis of skin cancer.

What is still being studied and where is medicine progressing?

Several innovations are developing in the field of skin cancer. These include digital dermoscopy, total-body skin mapping, artificial-intelligence-supported image analysis and personalised risk assessment. Artificial intelligence may help identify suspicious lesions, but it does not replace a dermatologist because diagnosis requires clinical context and often histological examination.

In oncology, immunotherapy and targeted-therapy approaches continue to develop for advanced melanoma, high-risk squamous cell carcinoma and other aggressive skin tumours. Researchers are also seeking better ways to distinguish low-risk lesions from those requiring rapid and more intensive treatment, with the aim of improving patient safety while avoiding unnecessary procedures.

Disclaimer

The information provided in this article is intended for informational and educational purposes only and does not replace medical consultation, diagnosis or treatment. Self-assessment of skin lesions can be inaccurate because skin cancer may resemble a benign lesion, while benign lesions may sometimes appear suspicious. If you notice a new, changing, bleeding, painful, itchy, non-healing or otherwise suspicious skin lesion, consult a dermatologist, dermato-oncologist or another appropriate specialist. Do not attempt to treat, burn, cut or remove suspicious lesions yourself. If symptoms deteriorate rapidly, the lesion grows quickly, bleeds heavily, causes severe pain, develops purulent inflammation or is accompanied by enlarged lymph nodes, urgent medical assessment is required.

References and authoritative sources

• Centre for Disease Prevention and Control of Latvia (SPKC): Do not burn — choose life
• Centre for Disease Prevention and Control of Latvia (SPKC): Safe sun exposure
• World Health Organization (WHO): Ultraviolet radiation
• US National Cancer Institute (NCI): Definition of skin cancer
• US National Cancer Institute (NCI): Skin cancer treatment — patient information
• US National Cancer Institute (NCI): Skin cancer treatment — health professional information
• American Academy of Dermatology (AAD): Common types of skin cancer
• American Academy of Dermatology (AAD): Skin cancer types and treatment
• American Academy of Dermatology (AAD): Actinic keratosis overview
• NHS: Non-melanoma skin cancer overview
• NHS: Non-melanoma skin cancer symptoms
• NHS: Non-melanoma skin cancer treatment
• NHS: Melanoma symptoms
• Cancer Research UK: Types of skin cancer
• Cancer Research UK: Skin cancer symptoms and photographs
• Macmillan Cancer Support: Skin cancer
• Skin Cancer Foundation: Skin cancer photographs and possible appearances
• European Association of Dermato-Oncology (EADO): European guidelines
• European Journal of Cancer: European interdisciplinary guidelines for the diagnosis and treatment of basal cell carcinoma
• PubMed: European interdisciplinary guidelines for the diagnosis and treatment of melanoma — Part 1
• PubMed: European interdisciplinary guidelines for the diagnosis and treatment of melanoma — Part 2

Content author

Dermatologist Dr. med. Dace Buile