Interdigital Corns (Heloma Molle): Why Painful Soft Corns Form Between the Toes
6 October 2026
By Mark Reyneker, BTech (Podiatry), MSc (Palaeontology), Registered Podiatrist, Foot & Gait Specialist | Founder & Clinical Director, Family Podiatry Centre
Published: 6 October 2026 | Last reviewed: 5 October 2026
A painful spot between the toes can be surprisingly uncomfortable. It may feel as though there is a small stone, sharp piece of skin or foreign object trapped between the toes, yet when you look at the area there may be little more than a small white patch of thickened skin.
A painful spot between the toes can be surprisingly uncomfortable. It may feel as though there is a small stone, sharp piece of skin or foreign object trapped between the toes, yet when you look at the area there may be little more than a small white patch of thickened skin.
One possible cause is an interdigital corn, medically known as a heloma molle, or soft corn.
Unlike the dry, hard corns that commonly develop on the tops of toes, an interdigital corn forms where two neighbouring toes repeatedly press against one another. The skin responds to this mechanical stress by producing additional keratin. Because the lesion sits within the warm, relatively moist environment between the toes, that thickened keratin absorbs moisture and becomes soft and macerated.
The important point is that a heloma molle is therefore not simply a superficial skin problem. In many cases, there is a mechanical reason why that particular piece of skin is repeatedly being compressed.
Understanding that mechanism helps explain why interdigital corns can become extremely painful — and why some return repeatedly after the visible corn has disappeared.
What is a heloma molle?
A heloma is a localised area of mechanically induced hyperkeratosis — an excessive accumulation of keratin in response to repeated pressure or friction. Corns differ from broad areas of callus because they are generally more focal and circumscribed, often developing a concentrated central keratinous component.
The two traditional forms are:
- Heloma durum — the hard corn, generally dry and firm.
- Heloma molle — the soft or interdigital corn.
Interdigital corns consist of localised hyperkeratotic tissue developing between opposing surfaces of adjacent toes. They are particularly associated with the fourth interdigital space between the fourth and fifth toes, although they can occur elsewhere (Day, Reyzelman and Harkless, 1996; Martí-Martínez et al., 2019).
The word molle refers to the lesion's soft consistency. Importantly, it is not moisture that initially creates the corn. Mechanical stress creates the corn. Moisture changes the character of the keratin and makes it soft. That distinction is central to understanding the condition.
Why does an interdigital corn form?
At its simplest, a heloma molle develops because a small area of skin becomes repeatedly compressed between two surfaces. Those surfaces are usually neighboring toes. The process can be thought of as a sequence.
1. The toes are pushed against one another
The lesser toes are not simply soft structures. Each contains three phalanges, with relatively prominent bony regions surrounding the interphalangeal joints. If the alignment or relative position of two neighbouring toes places these prominences opposite each other, the skin between them may become trapped. Footwear can then add another component.
A shoe with insufficient space across the forefoot can compress the toes from the outside, increasing pressure between them. However, footwear is often only part of the explanation. Earlier investigations into interdigital corns found that underlying congenital or acquired anatomical factors frequently predisposed particular bony surfaces to oppose one another (Gillet, 1979).
This helps explain something commonly seen clinically: two people can wear similar shoes, yet only one repeatedly develops a corn in exactly the same interdigital location. Their underlying toe geometry may be different.
2. Repetitive pressure stimulates the epidermis
Skin is biologically responsive to mechanical loading. When an area is repeatedly exposed to excessive friction, compression or shear, one of its protective responses is to increase the thickness of the epidermis, particularly the keratinised outer layers. This is hyperkeratosis.
In a broad region, that response may produce a callus. When the stress is highly concentrated in a small area, however, the response can become much more focal and produce a corn. Corns are therefore not random collections of dead skin. They represent a local biological response to repetitive mechanical stress (Freeman, 2002). Research examining mechanically induced hyperkeratotic lesions has also demonstrated that areas of callus are associated with increased local pressure, reinforcing the relationship between tissue loading and keratin formation (Menz, Zammit and Munteanu, 2007).
3. The corn becomes increasingly concentrated
Continued mechanical loading causes keratin to accumulate at the site. Unlike a broad callus, a corn tends to develop a concentrated central region. This has traditionally been described as a central core or nucleus. The term can occasionally cause confusion because this is not a root growing into the body. Rather, the geometry of the compacted keratin means that pressure applied to the surface can become concentrated towards the deeper viable tissues.
This helps explain the disproportionate pain. A lesion only a few millimetres across can hurt considerably because every step, shoe compression or movement of the neighbouring toe can repeatedly drive pressure through a very small area. Helomas have been described histologically and clinically as circumscribed hyperkeratotic lesions arising through epidermal hyperplasia following excessive pressure and friction (Martí-Martínez et al., 2019).
4. Moisture transforms the lesion into a “soft” corn
Between the toes, the environment is very different from the exposed skin on the top of a toe.
The interdigital space has:
- limited air circulation,
- close skin-to-skin contact,
- perspiration,
- increased local humidity,
- and frequently prolonged enclosure inside footwear.
Keratin readily absorbs moisture. Consequently, the corn becomes macerated.
Instead of looking yellow, dry and hard like a typical heloma durum, a heloma molle may appear:
- white,
- grey-white,
- pale,
- rubbery,
- soft,
- moist,
- or slightly peeling.
Peer-reviewed descriptions of interdigital helomas specifically identify this absorption of perspiration as the reason for their characteristic macerated appearance (Martí-Martínez et al., 2019). This gives us a useful way of understanding the pathology: Pressure produces the hyperkeratosis. Moisture produces the maceration. Both processes are occurring at the same location.
Why are interdigital corns so painful?
People are often surprised that such a small lesion can produce so much discomfort. There are several reasons.
The first is pressure concentration.
A broad callus distributes load over a comparatively large area. A corn concentrates force into a considerably smaller region.
The first is pressure concentration.
A broad callus distributes load over a comparatively large area. A corn concentrates force into a considerably smaller region.
The second is anatomical location.
An interdigital corn may effectively become trapped between two firm neighbouring structures. Every time the shoe compresses the toes, the lesion is squeezed again.
An interdigital corn may effectively become trapped between two firm neighbouring structures. Every time the shoe compresses the toes, the lesion is squeezed again.
The third is inflammation.
If repeated mechanical loading persists, the tissues beneath and around the corn can become inflamed. With sufficient ongoing pressure, skin breakdown or ulceration can occur (Martí-Martínez et al., 2019).
If repeated mechanical loading persists, the tissues beneath and around the corn can become inflamed. With sufficient ongoing pressure, skin breakdown or ulceration can occur (Martí-Martínez et al., 2019).
Patients may consequently describe:
- a sharp focal pain,
- burning,
- tenderness when wearing closed shoes,
- pain when the neighbouring toes press together,
- or the sensation that something is stuck between the toes.
Removing the shoe can make the discomfort settle surprisingly quickly because the external compressive force decreases.
Why do they occur so often between the fourth and fifth toes?
Although a soft corn can occur between different toes, the fourth interdigital space is the classic location. This observation is not new. In a large historical series of more than 1,000 interdigital corns, Gillet reported that 65% occurred within the fourth interspace. The majority of those lesions occurred where particular regions of the fourth and fifth toes opposed one another (Gillet, 1979).
More recent literature continues to identify the fourth interspace as the most frequent location for interdigital helomas (Martí-Martínez et al., 2019). One reason is the anatomy of the outer toes. Depending on toe length, rotation and alignment, a prominence from one phalanx can lie directly opposite a prominence from the neighbouring phalanx. The skin is then repeatedly compressed between them. The fifth toe is particularly variable in its position and may rotate, curl or move beneath or against the fourth toe.
Other structural factors reported in the literature include differences in metatarsal length, hammer or curled lesser toes and hallux valgus-associated digital displacement (Gillet, 1979). This does not mean every interdigital corn has exactly the same anatomical cause. It means the location of the corn can provide a clue to where the repetitive mechanical stress is occurring.
Shoes matter — but they may not be the whole explanation
Tight or narrow footwear can undoubtedly increase interdigital compression. A narrow toe box squeezes the lesser toes together. If a bony prominence is already positioned opposite another toe, the shoe can amplify that contact dramatically. Activity can further increase the number of repetitive loading cycles. But simply concluding that the shoe is “too tight” may sometimes oversimplify the problem.
A person may have worn the same style of footwear for years before symptoms develop. Others may experience the same corn repeatedly even after changing shoes. In such cases, it becomes important to consider the relationship between: footwear + toe structure + toe alignment + activity + skin environment. The corn is developing where those factors converge.
Why does a soft corn sometimes look wet or white? This is maceration.
Maceration occurs when the stratum corneum absorbs water and becomes overhydrated. Between tightly opposed toes, sweat does not evaporate particularly efficiently. The thickened keratin of the corn can therefore remain moist for prolonged periods. The result may resemble soggy white skin. Because moisture changes the appearance of the lesion so dramatically, patients sometimes assume they have a fungal infection.
However, a soft corn and a fungal infection are not the same condition. That said, they can coexist. Persistent interdigital moisture and damaged skin can provide an environment in which fungal or bacterial organisms may proliferate. Secondary infection has therefore been described as a potential complication of interdigital helomas (Martí-Martínez et al., 2019).
Is an interdigital corn contagious?
The corn itself is not contagious. It is a mechanically induced hyperkeratotic lesion rather than an infectious disease. This is another reason accurate diagnosis matters. Several conditions occurring between or around the toes can resemble one another clinically, yet their underlying causes are completely different.
What else can look like an interdigital corn?
Not every painful area of thickened or white skin between the toes is a heloma molle. Depending on its appearance and location, a clinician may need to consider several possibilities.
Fungal infection
Interdigital tinea pedis can produce white macerated skin, scaling, fissuring and irritation between the toes. It may also coexist with a corn.
Bacterial toe-web infection
Persistently moist interdigital spaces can develop bacterial infection. More severe forms may produce considerable maceration, odour, erosion, discharge or surrounding inflammation.
Verruca
A viral wart may occasionally be mistaken for a corn, particularly when hyperkeratosis obscures its surface. Dermoscopy can help distinguish the two.
In one study, corns characteristically demonstrated a translucent central core, whereas plantar warts showed vascular red or black dots and interruption of normal dermatoglyphics (Patil et al., 2023).
In one study, corns characteristically demonstrated a translucent central core, whereas plantar warts showed vascular red or black dots and interruption of normal dermatoglyphics (Patil et al., 2023).
Interdigital skin breakdown
Fissuring, erosion or early ulceration may occur where the skin remains moist and subjected to repeated compression.
Other dermatological lesions
Less common dermatological conditions can occasionally mimic more routine interdigital pathology. This is why repeatedly treating something simply because it “looks like a corn” may not always solve the problem.
Why does the same corn keep coming back?
This is perhaps the most important part of understanding heloma molle. The keratin that you see is the tissue response. The mechanical environment that created it may still be present. If the same two areas of the toes continue pressing together, the skin is once again exposed to the same repetitive stimulus. It may therefore begin producing hyperkeratosis again.
This helps explain the familiar cycle: pressure → hyperkeratosis → painful corn → temporary improvement → pressure returns → corn returns.
The scientific literature on interdigital corns has long emphasised the importance of identifying the underlying predisposing anatomy and mechanical forces rather than viewing the lesion in isolation (Day, Reyzelman and Harkless, 1996; Gillet, 1979). A recurrent interdigital corn is therefore clinically useful information. Its recurrence suggests that the mechanical environment at that location has probably not changed sufficiently.
The scientific literature on interdigital corns has long emphasised the importance of identifying the underlying predisposing anatomy and mechanical forces rather than viewing the lesion in isolation (Day, Reyzelman and Harkless, 1996; Gillet, 1979). A recurrent interdigital corn is therefore clinically useful information. Its recurrence suggests that the mechanical environment at that location has probably not changed sufficiently.
How is an interdigital corn assessed?
Assessment involves more than simply confirming that thick skin is present. The clinician needs to establish why that particular area is being loaded.
This may involve examining:
- the precise location of the lesion,
- which two surfaces of the toes oppose one another,
- the alignment and rotation of the lesser toes,
- the prominence of the underlying joints or phalanges,
- the shape and fit of footwear,
- whether the lesion changes during weightbearing,
- the condition of the surrounding interdigital skin,
- and whether infection, ulceration or another diagnosis is present.
For recurrent lesions, the relationship between the underlying bones may also become clinically relevant. The objective is therefore not merely to identify a “corn”. It is to understand the mechanical architecture surrounding the corn.
How are interdigital corns treated?
Treatment depends on the cause, severity, recurrence pattern, condition of the skin and health of the patient.
In broad terms, management has two objectives:
1. Relieve the painful lesion.
2. Reduce the mechanical forces responsible for producing it.
Professional treatment may therefore involve addressing the hyperkeratotic lesion itself while simultaneously looking for ways to reduce pressure between the involved toes. Footwear is often considered because external compression may be contributing to the problem. Where toe position or another structural factor is responsible, management may also need to address the underlying mechanics rather than repeatedly focusing only on the skin.
Conservative treatment is generally the initial approach. In persistent recurrent cases in which a clearly identifiable structural prominence continues producing pressure despite appropriate conservative management, surgical correction may occasionally be considered. A prospective multicentre cohort study has investigated minimally invasive correction for chronic recurrent interdigital corns, demonstrating that structural treatment can be relevant in appropriately selected cases (Martí-Martínez et al., 2021).
The appropriate option therefore depends on what is actually producing the corn.
Why simply removing the thick skin may not be enough
Reducing a painful accumulation of keratin can make an interdigital corn feel considerably better because it removes material through which pressure is being transmitted.
But this does not necessarily change:
- the position of the toes,
- the underlying bony prominences,
- the width of the shoe,
- or the compressive forces acting between the digits.
If those factors remain unchanged, the epidermis may simply respond again. This is why a recurring corn warrants a slightly different question.
Instead of asking: “How do I remove this corn?” it may be more useful to ask: “Why does my skin keep producing a corn in exactly this location?”. That question leads back to the underlying mechanics.
Instead of asking: “How do I remove this corn?” it may be more useful to ask: “Why does my skin keep producing a corn in exactly this location?”. That question leads back to the underlying mechanics.
Should you cut an interdigital corn yourself?
Cutting deeply into an interdigital corn yourself is not advisable. The skin between the toes can already be macerated and fragile, and it is easy to mistake normal or damaged tissue for thickened keratin. Chemical corn-removing preparations can also damage surrounding healthy skin if used incorrectly.
This becomes considerably more important in people with diabetes, peripheral neuropathy, impaired circulation or a history of foot ulceration. International diabetic-foot guidelines regard pre-ulcerative lesions and abnormal mechanical loading as clinically important and recommend professional management of such risk factors rather than unsupervised treatment (Bus et al., 2024; Schaper et al., 2024).
When should an interdigital corn be examined?
Consider arranging an assessment if:
- the corn is painful,
- it repeatedly returns,
- you are uncertain whether it is actually a corn,
- the skin is breaking down,
- there is redness, swelling, discharge or increasing warmth,
- the area appears infected,
- changing footwear has not resolved the problem,
- the toes appear significantly rotated or deformed,
- or you have diabetes, neuropathy or circulation problems.
A recurrent lesion between exactly the same two toes usually deserves investigation of why those surfaces continue contacting one another.
Interdigital corns are small lesions with a mechanical story
A heloma molle can look deceptively simple. There may only be a few millimetres of white thickened skin between two toes. But underneath that small lesion is often a repeated mechanical process. Two neighbouring structures compress the skin. The epidermis responds by producing additional keratin. The interdigital environment keeps that keratin moist. The corn becomes macerated.
Pressure becomes concentrated through a small area. And the lesion becomes painful. If the mechanical forces continue, the cycle can repeat. This is why identifying an interdigital corn is only the first part of the diagnosis. The more useful question is: Why is a corn forming at this exact location between these particular toes?
At Family Podiatry Centre, assessment of recurrent interdigital corns focuses on identifying the lesion, examining the surrounding skin and determining the mechanical and structural factors that may be creating repeated pressure between the toes. Understanding the cause allows treatment to be directed at more than simply the visible thickened skin.
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Disclaimer: The word "treatment" in this article refers to the care and management of a patient’s health to prevent, cure, or improve a condition. Treatment results vary and do not necessarily indicate a cure. This article is for informational and educational purposes only and does not constitute medical advice.
About the Author
Mark B. Reyneker, BTech (Podiatry), MSc (Palaeontology) is a podiatrist and Founder & Clinical Director of Family Podiatry Centre, with more than 25 years of clinical experience across South Africa, Malaysia and Singapore. His clinical interests include foot and lower-limb pain, gait and biomechanics, sports-related foot conditions, orthotic therapy and footwear.
Alongside his clinical practice, Mark conducts research into human gait and foot biomechanics. His MSc research at the University of the Witwatersrand investigated human propulsion and the structural properties of the metatarsals. He is also the inventor of A Foot Orthotic, an orthotic technology developed through an international patent family.
Disclaimer: The word "treatment" in this article refers to the care and management of a patient’s health to prevent, cure, or improve a condition. Treatment results vary and do not necessarily indicate a cure. This article is for informational and educational purposes only and does not constitute medical advice.
About the Author
Mark B. Reyneker, BTech (Podiatry), MSc (Palaeontology) is a podiatrist and Founder & Clinical Director of Family Podiatry Centre, with more than 25 years of clinical experience across South Africa, Malaysia and Singapore. His clinical interests include foot and lower-limb pain, gait and biomechanics, sports-related foot conditions, orthotic therapy and footwear.
Alongside his clinical practice, Mark conducts research into human gait and foot biomechanics. His MSc research at the University of the Witwatersrand investigated human propulsion and the structural properties of the metatarsals. He is also the inventor of A Foot Orthotic, an orthotic technology developed through an international patent family.
Reference
- Bus, S.A. et al. (2024) ‘Guidelines on the prevention of foot ulcers in persons with diabetes (IWGDF 2023 update)’, Diabetes/Metabolism Research and Reviews, 40(3), e3651. DOI: 10.1002/dmrr.3651. DOI / PubMed
- Day, R.D., Reyzelman, A.M. and Harkless, L.B. (1996) ‘Evaluation and management of the interdigital corn: a literature review’, Clinics in Podiatric Medicine and Surgery, 13(2), pp. 201–206. PubMed record
- Freeman, D.B. (2002) ‘Corns and calluses resulting from mechanical hyperkeratosis’, American Family Physician, 65(11), pp. 2277–2280. PubMed record
- Gillet, H.G. (1979) ‘Interdigital clavus: predisposition is the key factor of soft corns’, Clinical Orthopaedics and Related Research, 142, pp. 103–109. PubMed record
- Martí-Martínez, L.M. et al. (2019) ‘Description of the surgical technique for condylectomy with minimally invasive surgery to treat interdigital helomas on the lesser toes: a Delphi study’, Journal of Foot and Ankle Research, 12, 13. DOI: 10.1186/s13047-019-0322-5. DOI / full article
- Martí-Martínez, L.M. et al. (2021) ‘Efficacy and safety of condylectomy with minimally invasive surgery in the treatment of interdigital corns of the lesser toes compared to conservative treatment’, Journal of Foot and Ankle Research, 14, 20. DOI: 10.1186/s13047-021-00460-0. DOI / full article
- Menz, H.B., Zammit, G.V. and Munteanu, S.E. (2007) ‘Plantar pressures are higher under callused regions of the foot in older people’, Clinical and Experimental Dermatology, 32(4), pp. 375–380. DOI: 10.1111/j.1365-2230.2007.02421.x. DOI / PubMed
- Patil, S. et al. (2023) ‘Dermoscopic findings in clinically diagnosed cases of plantar warts, corns, and calluses: a cross-sectional study’, Cureus, 15(4), e38093. DOI: 10.7759/cureus.38093. DOI / full article
- Schaper, N.C. et al. (2024) ‘Practical guidelines on the prevention and management of diabetes-related foot disease (IWGDF 2023 update)’, Diabetes/Metabolism Research and Reviews, 40(3), e3657. DOI: 10.1002/dmrr.3657. DOI / PubMed
Frequently Asked Questions
A heloma molle is a painful soft corn that develops between adjacent toes. It forms because of repetitive pressure or friction and becomes soft and white because the thickened keratin absorbs moisture within the interdigital space.
The fourth interdigital space is the most frequently reported location for soft corns. The shape, position or rotation of the fourth and fifth toes can cause neighbouring bony prominences to oppose each other, while footwear may further compress the toes.
No. A heloma molle is a mechanically induced hyperkeratotic lesion. However, the moist skin surrounding an interdigital corn can also develop fungal or bacterial infection, and the conditions may coexist.
A corn concentrates pressure into a very small area. When it lies between two opposing toes, every episode of shoe compression or toe movement can repeatedly load the same sensitive tissue.
If the underlying pressure between the toes remains, the skin continues receiving the mechanical stimulus that originally caused the hyperkeratosis. Recurrence may therefore indicate that the causative pressure has not been sufficiently altered.
Yes. Persistent maceration and skin breakdown can occasionally allow secondary fungal or bacterial infection to develop.
The thickened keratin absorbs moisture from perspiration. Because evaporation between closely opposed toes is limited, the skin becomes macerated and develops its characteristic white, soft appearance.
Self-treatment with chemical preparations requires particular caution because the healthy skin surrounding an interdigital corn is often thin and moist. People with diabetes, neuropathy or impaired circulation should have corns professionally assessed rather than attempting chemical or sharp self-treatment.
A corn concentrates pressure into a very small area. When it lies between two opposing toes, every episode of shoe compression or toe movement can repeatedly load the same sensitive tissue.
An assessment is advisable when the lesion is painful, repeatedly returns, appears infected or ulcerated, or when you are unsure whether it is actually a corn. Earlier professional assessment is particularly important for people with diabetes, neuropathy or impaired circulation.