Introduction

Most people take walking for granted, but for many, walking itself is a daily struggle. In fact, walking can cause a condition called podoconiosis, also known as non-filarial elephantiasis.¹ Podoconiosis can cause severe swelling (lymphoedema) and deformity of the feet and legs, thus affecting the ability to walk.¹ Consequently, this has significant impacts on an individual’s daily life. 

Podoconiosis is non-contagious and develops following long-term exposure of bare feet to irritant minerals found within soil, particularly in volcanic areas.¹ Although its name sounds similar to filariasis elephantiasis, the two diseases have different causes. While both conditions share similarities in symptoms, unlike podoconiosis, filariasis elephantiasis is caused by parasitic worms, which are transmitted by infected mosquitos.²

Despite affecting millions of people globally, podoconiosis is highly preventable.³ Using relatively simple, low-cost solutions and implementation of the correct hygiene measures, the disease can be prevented from affecting people entirely.

What are the causes of podoconiosis?

Unlike many diseases, podoconiosis is not caused by a bacteria or virus. It is instead a non-contagious condition that develops through prolonged contact between bare feet and irritant soil.¹ It is important to note that simply walking on the ground with your bare feet will not result in podoconiosis. Rather, the condition results from long-term unprotected exposure to these irritants. 

The exact cause of podoconiosis is currently unknown. However, researchers suggest that there is an influence from both environmental and genetic factors. Current evidence points toward an enhanced immune response within affected individuals, combined with the large variety of potential irritants within the soil.

Although it may sound alarming that you can acquire such a debilitating disease by walking on soil, it is not as simple as that. Those who develop podoconiosis typically reside within tropical highland regions, where such irritant soil is present.¹ 

However, manifestation of podoconiosis requires continuous, long-term exposure of bare feet to such conditions. The absence of the protective barrier offered by footwear allows irritants, such as magnesium, aluminum, and silicon, to penetrate the skin. These minerals are then absorbed into the lymphatic system, which results in a cascade of problems. 

The lymphatic system functions to remove any excess fluid from the body, preventing fluid buildup.⁴ When exposed to irritants, the body recognises them as foreign and will launch an immune response. Part of this immune response involves inflammation of the lymphatic system. Over time, chronic inflammation of an individual’s lymphatic system causes damage. Much like a faulty plumbing system, the lymphatic system becomes blocked with fluid and proteins, leading to a condition called lymphoedema. This is what causes the symptoms that are commonly associated with podoconiosis—hardened skin and swelling.⁵ 

What are the risk factors associated with podoconiosis?

Podoconiosis does not have a single cause. Instead, the condition develops through a variety of risk factors. While each risk factor has varying levels of importance, the combination of these factors increases an individual’s susceptibility to the disease. The risk factors can be categorised into the following:⁵

• Geographic factors
• Behavioural factors
• Socioeconomic factors

Geographic factors

Podoconiosis is caused by exposure to irritant minerals found within volcanic soil, most commonly red, clay-like soils located within tropical highland regions.⁶ These environments are characterised by high altitudes of over 1000 metres and an annual rainfall of over 1000 millimetres; such conditions facilitate the formation of the mineral-rich soil associated with podoconiosis.⁷

These regions are found throughout Africa, Central America, South America, and Southeast Asia, although Africa accounts for the majority of global cases of podoconiosis.⁸ This means that if you do not live or spend long periods of time in an area of risk, you will be unlikely to contract the disease.

Behavioral factors

Perhaps the most significant of the three factors is the behavioural factors. This is because even in high-risk areas, those who are not consistently walking barefoot on the soil will be unlikely to contract podoconiosis.

In contrast, those who walk barefoot on irritant soil over long periods of time are highly susceptible to developing podoconiosis. Such long-term exposure is often associated with professions requiring extended contact with soil, such as farmers.¹ Thus, certain occupations, especially in high-risk regions, are associated with greater risk of disease.

Socioeconomic factors

Socioeconomic factors can influence and exacerbate behavioural risks for contracting podoconiosis. For example, poverty can often cause these behavioural decisions. Individuals living in poverty-stricken conditions likely have limited access to protective footwear and basic hygiene resources. Not only that, these individuals are often forced into laborious professions or have to involuntarily walk barefoot on irritant-containing soil. As a result, podoconiosis disproportionately affects those living in impoverished communities, thus continuing the cycle of ill health and social inequality that is common amongst these communities.⁶

Where is podoconiosis found?

Podoconiosis is non-contagious and only poses a threat to people in regions containing the right conditions for its development. Specifically, podoconiosis risk increases in highland regions with volcanic soil.¹ 

However, not all highland areas are affected—tropical climates are also required. Most cases of podoconiosis are found within Africa, with the highest number of cases being in Ethiopia.¹ 

According to the World Health Organisation (WHO), podoconiosis is found within three main regions, affecting 17 counties: 

• 12 countries in Africa
• 3 countries in Central and South America
• 2 countries in Asia 

This distribution in the occurrence of podoconiosis corresponds to the fact that these regions have a large quantity of areas with high-altitude, volcanic landscapes and tropical rainfall, creating the soil conditions necessary for podoconiosis to occur.

Diagnosis and treatment

Why is it important?

Podoconiosis develops gradually, beginning with an early phase called pre-elephantiasis.⁷ If the disease is detected in this phase, complete recovery is possible. 

However, limited public knowledge in at risk areas means there is often a lack of adequate diagnostic tools. Consequently, early diagnosis is a prevalent challenge. In fact, many individuals are diagnosed only after complete disease onset, leading to lifelong complications. 

As podoconiosis cannot spread from person to person, it is highly controllable. This emphasises the importance of providing the correct education, diagnostic tools, and treatment to those at risk to reduce the prevalence of podoconiosis in high-risk regions. 

Diagnosis

Once symptoms appear, diagnosis is relatively simple. Typical signs include:

• Swelling and hardening of the skin on the feet and legs 
• A history of prolonged exposure of bare feet to irritant soil 

Observing these signs can lead to a diagnosis. 

However, due to the limited public knowledge regarding podoconiosis and its close similarities to filarial elephantiasis, misdiagnosis can occur, particularly during early stages of the disease.¹ 

In high-risk areas, such limited knowledge is exacerbated due to scarce healthcare funding. This means early detection, when in the reversible stage, is often not possible because of a lack of diagnostic tools, leading to lifelong disabilities.

Treatment

If detected early, podoconiosis can be treated. However, treatment for later stages of the disease focuses on managing symptoms, preventing further progression, and improving mobility and thus quality of life.¹ Fortunately, treatment methods for podoconiosis are simple and cost-effective when properly implemented. The main treatment areas include:

• Foot hygiene
• Protective footwear
• Management of lymphedema

Foot hygiene

Consistent foot hygiene can be effective with managing symptoms and reversing the early effects.¹ Regular washing of feet with soap and water helps remove irritant soil particles. In turn, this will protect the skin and prevent the entering of these irritant minerals into the lymphatic system and cause damage. Together, this can help prevent the onset of podoconiosis.

Protective footwear

Those living in high-risk regions must wear shoes. Shoes will act as a protection for the individual’s foot, protecting them against irritants entering and damaging their lymphatic system. 

While footwear cannot cure advanced cases of podoconiosis, it is effective for prevention during early stages of the disease.

Management of lymphoedema

Podoconiosis causes lymphoedema, which can be visualised with swelling in a patient’s feet and legs. Management of lymphedema aims to counter the swelling and includes:¹ 

• Elevating a patient’s legs 
• Applying compression to swollen areas 
• Daily exercises 

If performed correctly, these actions can not only reduce swelling but also improve the mobility of a patient and therefore their quality of life. 

Summary

Podoconiosis is a highly preventable disease caused by irritants found within volcanic soil. It poses a threat to those in high-risk regions, particularly impoverished communities. However, with the correct funding and education, the disease can be eradicated. As podoconiosis can be treated entirely if detected in its early stages, this should be the target area. With relatively little funding, the correct education regarding hygiene can be given, and also protective footwear can be distributed. If done correctly, future generations could be entirely protected from contracting podoconiosis.