7 very common skin diseases and their relationship with genetics

Some of the most common skin diseases are caused by infections, and others are the result of genetic factors combined with environmental factors. In this article, we bring you some examples of skin diseases caused by different factors, describing their symptoms, treatment and how to prevent them. 

Skin and dermatology

To learn  more about the characteristics of the skin, we recommend reading previous articles such as Rare Skin Diseases and their relationship with genetics or Basic Care of Sensitive Skin. In them we explain in detail, amongst other things, that the skin is the largest organ of the human body, and that it is formed by three layers: the epidermis, the dermis and the hypodermis. The skin performs several functions, among which we can highlight its role as a protective barrier, defending our body from aggressions by external agents such as viruses and bacteria.

This protective ability may be impaired if an element causes inflammation or irritation of the skin. Dermatology is the discipline which covers the study, prevention and treatment of the various pathologies that affect the skin, as well as how best to care for healthy skin. Pathologies that affect the skin can range from primary skin diseases to systemic diseases whose symptoms manifest via the skin. Most skin diseases are not severe. Nevertheless, they often lead to annoying symptoms that can also influence the patient’s mood, since most of them are usually visible. 

7 common skin diseases and their origin

The origin of skin diseases can be very diverse. As we mentioned earlier, some are the result of fungal or viral infections, while others involve environmental and genetic factors or may even be caused by immunological problems. 

Next, let’s look at some of the most common skin diseases, including one which has been worryingly on the rise in recent years: melanoma, which is a type of skin cancer. 

Vitiligo

Vitiligo is characterised by the appearance of white patches of varying sizes in different parts of the body, mainly in those most exposed to the sun, such as hands, arms, face and feet. These patches have well defined edges and sometimes have a darker or more reddish appearance. In addition, vitiligo often leads to the early appearance of grey hair, especially in the areas affected by the patches.

The disease occurs as a result of the destruction or improper functioning of melanocytes, the cells that produce melanin (a pigment that determines the colour of hair and skin). Although it affects all skin types, it is therefore more noticeable in dark-toned skins.

It is not contagious nor does have a serious prognosis; however, it increases the susceptibility to sunburn or skin cancer, amongst other complications. Skin affected by vitiligo rarely regains its colour, and the lack of pigmentation tends to spread to further parts of the body.

Once the vitiligo is diagnosed, treatments to rebalance skin tone may be proposed, including:

• Depigmentation of non-affected areas.
• Medications with steroid creams.
• Activation of melanocytes by exposure to UVA rays.
• Surgery.

The cause of the disease is still unknown, although many studies indicate that a combination of genetic and environmental components may be responsible.

Specifically, research suggests that vitiligo has a polygenic inheritance pattern, i.e., multiple alleles contribute to the genetic risk of the disease.

The relationship between genetics and the development of vitiligo has long been suspected, since first-degree relatives of people with vitiligo have a higher incidence of vitiligo than the general population. In particular, siblings of affected people have a prevalence of 6%, which increases to 23% in the case of twins.

Regarding environmental factors, it has been observed that exposure to various chemicals, such as phenolic compounds, alter melanin synthesis and can therefore trigger vitiligo.

Acne

Acne is the most common and best known skin disease. It has a prevalence of 80% in people between 11 and 30 years of age, although its peak incidence is reached in women between 14 and 17 years of age and in men between 16 and 19.

In general, regardless its severity, acne usually remits spontaneously between the ages of 20-25, although some women suffer from it beyond the age of 40.

The disease is characterised by the appearance, usually on the face, of comedones (sebum-filled spots) that can rupture and become infected, turning into pustules or even forming cysts.

Acne occurs because hair follicles become clogged with dead skin cells, bacteria, or dry sebum that builds up and blocks the path of the sebum that needs to come to the surface of the skin, exiting from the pores.

Depending on the damage to the skin, and the number of spots present, acne can be mild, moderate, or severe.

It is a multifactorial disease – that is, it is caused by the intervention of several factors – including genetic and environment.

Several studies have recently shown that acne can be inherited. Recent research by the King’s College dermatology institute and geneticists from the same university found 15 acne-related genetic variants which influenced the shape of hair follicles, making them more susceptible to bacterial inflammation.

The trigger for acne is usually found in the hormonal changes of puberty, in particular an increase in androgens, which causes the stimulation of the sebaceous glands.

Although it usually disappears spontaneously, a dermatologist may recommend treatments to alleviate the appearance of acne.  

Skin cancer

This type of cancer arises when abnormal skin cells grow uncontrollably, due to DNA damage caused mainly by ultraviolet radiation.

Although it is more common in areas of the body that are generally exposed to the sun, such as the face, neck, chest, arms, and legs, it can also occur in areas that are not normally exposed, such as the palms of the hands or under the nails.

Among the different types of skin cancer, melanoma is the most dangerous, since in its advanced stages it can spread to internal organs and therefore put the person’s life at risk.

It is usually curable if detected early, so it is important to pay close attention to its initial manifestations, including:

• Large brown spots with smaller dark specks.
• Moles that change in size or colour, or bleed.
• Small lesions with irregular borders and reddish, white or bluish parts.
• Moles or lesions that itch or burn.
• Dark lesions in the palms of the hands, soles of the feet, or mucous membranes of the mouth, nose, vagina, or anus.

The number of melanoma cases has tripled in the last 20 years. The proliferation of outdoor activities and tanning salons are some of the reasons that are considered to explain this large increase.  

The main treatment for this type of skin cancer is surgery to remove the damaged tissue.  If the cancer is advanced, chemotherapy, radiation therapy, or immunotherapy are used to slow the progression of the disease.

Environmental and genetic factors are involved in the development of this disease. In approximately 10% of cases, melanoma occurs in several members of the same family. These familial cases are usually due to inherited genetic changes that increase the risk of developing this type of cancer. Today, several genes associated with melanoma are known, although the most well documented are CDKN2A and MC1R.

As for environmental factors, intense exposure to the sun stands out. For this reason we must be aware of the importance of wearing protection, especially on the face, all year round, as we’ve explained in the post The importance of using sunscreen all year round. 

Athlete’s foot

This skin disease is an infection caused by a fungus, and usually starts between the toes. The disease is characterised by rashes that may be accompanied by itching and burning and may cause flaking.

Athlete’s foot is very contagious, as it can easily spread to other parts of the body of the affected person or to other people through contact with the infected part or by sharing towels, for example.

The fungus that causes athlete’s foot is the same one that causes ringworm. It is a microorganism which proliferates in humid and warm environments. That is why the risk of getting this skin disease is increased by behaviours such as:

• Regularly wearing wet or very tight socks and shoes.
• Sharing shoes, bedding, or mats with someone who has the infection.
• Walking barefoot in public places where conditions favour the development of the fungus, such as saunas, changing rooms, swimming pools or shared showers.

Athlete’s foot is treated with antifungal creams, which remove the fungus.

Warts

Warts are benign epidermal prominences that can appear anywhere on the body, although they are more common on fingers and hands.

They are usually asymptomatic, although sometimes they can cause mild pain, and although they usually disappear on their own after a couple of years, they can also be eradicated earlier with treatments such as the application of drugs containing salicylic acid, or cryotherapy, which consists of applying liquid nitrogen to the wart.

Warts are caused by some types of human papillomavirus, of which there are over 150 types.

Viruses that cause warts can be spread by skin contact or by sharing objects. 

Because it is an infection, each person responds differently depending on their immune system, therefore young children or individuals with weakened immune systems (such as people with AIDS or transplant patients) are more vulnerable.

Psoriasis

Psoriasis is caused by an acceleration of the life cycle of skin cells which causes them to accumulate on the surface of the skin, resulting in reddish scales and patches that cause itching and even pain.

Symptoms vary in each person, but the most common are:

• Red patches on the skin covered with scales.
• Dry, cracked skin that can even bleed.
• Itching, burning and pain.
• Nails that are thicker than normal and cracked.
• Swollen joints.

Psoriasis usually involves skin damage (cuts, burns, etc.) that trigger the outbreak which can last for weeks or months and then decrease in severity, although they reoccur after a while, as this is a chronic disease. The main objective of the treatment is to control the symptoms, which has three approaches:

• Topical: creams, usually containing corticosteroids, that are applied in mild cases of psoriasis.  
• Phototherapy: this is based on radiation with ultraviolet light, either natural or artificial.
• Systemic medications, such as retinoids, are used in more severe cases of psoriasis or when psoriasis is resistant to other treatments.

Psoriasis is multifactorial, as both genetic and environmental factors are involved.

Having parents with psoriasis has been shown to increase the risk of getting psoriasis. In a meta-analysis comparing genetic variations in 39,000 participants, 16 markers associated with psoriasis were identified. 

Environmental factors that increase the likelihood of psoriasis include a weakened immune system, high levels of stress, obesity, or smoking.

As you can see, many skin diseases, including melanoma, are associated with a genetic risk. Advances in genetic research into this type of condition will enable the development of personalised medicine resulting in more precise diagnostic methods and treatments. At Veritas we encourage you to take a proactive attitude to looking after your health in order to achieve complete well-being and prevent these and other conditions. Don’t hesitate to contact us for more information.