Calluses, corns and heel fissures

Podiatry FOCUS
Calluses, corns and heel
fissures
Farina Hashmi
Hypertrophy of the plantar stratum corneum (SC) of the epidermis (also known as hyperkeratosis)
is one of the skin’s primary protective responses, triggered by either physiological stresses, a result of
underlying disease (eg, psoriasis, palmoplantar keratoderma), or external mechanical stresses. In the case
of the foot the most common presentations of hyperkeratosis are: anhidrosis, calluses, corns and heel
fissures. This article reviews the current evidence in the field of hyperkeratosis of the foot and will present
the treatment options available to practitioners and patients. The gaps in the knowledge surrounding
the efficacy of treatments are discussed and novel methods for the measurement of the formation and
regression of hyperkeratosis are introduced.
Anhidrosis
Anhidrosis (or xerosis) often implies
poor tissue nutrition, which can be
multifactorial in origin and can include:
hypothyroidism, peripheral autonomic
neuropathy, increasing age (Gniadecka,
Jemec, 1998) and peripheral vascular
disease. The primary aim of the treatment
of anhidrosis is the restoration of the SC
layer to a ‘normal’ state. This is achieved
by the topical agents that encourage the
absorption of water into the SC (Potts,
1986). The most effective compounds
that achieve this increase in hydration are
emollients, barrier creams and occlusive
materials (gel-based materials). Anhidrotic
skin, particularly in the elderly, can be
related to itching. The use of emollients
with antipruritics can be beneficial in such
cases (Yosipovitch, 2004). In the context
of the foot, anhidrotic skin can increase
the risk of fissuring and the formation
of corns and callus. Other than extrinsic
factors (such as footwear and abnormal
walking patterns), the hydration of the
SC will have a considerable effect on
the mechanical nature of the skin and its
response to the external stresses of gait.
Figure 1. Heel fissures and hyperkeratosis on the heel of the foot.
Underlying systemic disease,
such as dermatitis or eczema,
and local infection, such as
tinea pedis, can exacerbate
fissuring of the skin.
Heel fissures are dry cracks in the
epidermis (Figure 1) often located on the
periphery of the heel where the heel
skin is subjected to high tension stresses
(Springett, Johnson, 2010). Underlying
systemic disease, such as dermatitis or
eczema, and local infection, such as tinea
pedis, can exacerbate fissuring of the skin.
Most often the fissures remain confined
within the epidermis; however they can
run deeper in the dermis, placing the foot
at risk of bacterial infection.
Dr Farina Hashmi, PhD, FCPodMed, is a
Research Fellow at the School of Health, Sport
and Rehabilitation Sciences, University of Salford
If there is a known, treatable
underlying cause, for example tinea
infection, this must be treated in the first
Heel fissures
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Podiatry-mj-Cjp3.indd 40
instance. The mainstay of treatment is
aimed at restoring the physical integrity
of the SC via reducing the hyperkeratotic
tissue and restoring water content. This is
achieved by urea-based emollients (25%),
which have a dual effect of providing
keratolysis and hydration. Use of these
emollients alone can eliminate heel
fissures in some cases, but not all (Figure
2). It appears that the severity of the
fissures at the point of commencement
of treatment is indicative of how effective
emollients therapies can be. Due to this
variation in treatment outcomes, it would
be helpful to gain a greater understanding
of the nature of the fissured skin and its
response to specific treatment regimes so
that appropriate treatments for different
types of fissures can be adopted.
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04/03/2013 11:09
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a
b
c
d
Figure 2. Heel fissure before treatment (a and c) and after 2 weeks of treatment with 25% urea
emollient (b and d).
Figure 3. Common sites of plantar callus.
From a podiatrist’s perspective, the
physical removal of the hyperkeratosis
associated with heel fissures can
be successfully achieved via scalpel
debridement and filing, with subsequent
emollient application as a preventative
measure. If the fissures are particularly
deep, the use of medical grade acrylic
glue or adhesive skin closure may be an
option (Hashimoto, 1999). Longhurst and
Bristow also published a clinical study for
this purpose (2010).
may have on general health and quality
of life.
Callus and corns
Incidence
Incidence data captured from several
surveys investigating foot health were
collated by Farndon et al (2006).
They found that up to 78% of people
surveyed had corns and callus. There
were variations in incidence figures
between studies mainly due to some
studies publishing patient self-reported
assessments and others recorded
assessments conducted by healthcare
professionals. As would be expected,
the latter produced higher incidence
rates due to the increased experience
of the examiner. A European survey
of 70,000 patients also confirmed the
high prevalence of foot diseases in
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Podiatry-mj-Cjp3.indd 41
Most recent figures show
2 million people are treated
annually by the NHS [for
foot pathologies], and
769,000 of these are new
episodes of care.
Europe (Burzykowski et al, 2003). The
high incidence of foot pathologies in the
population is reflected in the number
of people accessing podiatry care. Most
recent figures show 2 million people are
treated annually by the NHS; 769,000 of
these are new episodes of care, of which
56% are for older people (Health and
Social Care Information Centre, 2005).
In the case of diabetes, the development
of callus is one of the most common
problems associated with the feet and, in
such a high-risk group, is a warning sign
for ulceration (Murray, 1996, Reiber, 1999,
Jones, 1998). In the older population
corns and callus can have a negative
impact on balance and can increase the
risk of falls (Menz, Lord, 2001, Mickle et al,
2010). With the increase in population of
older people and people with diabetes,
it is therefore vital that the care for feet
begins at early stages to prevent the
detrimental effects that corns and calluses
Pathophysiology and clinical presentation
Callus is described as mechanically
induced hyperkertosis (Thomas et al,
1985), which has a yellow hue. Callus
presents as a plaque of hard skin (SC) on
points on the foot that are susceptible to
high mechanical loads, commonly the top
of the digits and the plantar surface of the
forefoot (Figure 3).
Although mechanical load is the most
likely cause of callus formation, it is not
clear what types of mechanical loads (for
example compression, shear or torsion)
or how much load is required to trigger
the hyperkeratosis process. What is known
is that trauma of the skin leads to the
release of local growth factors (McKay,
Leigh, 1991). It is hypothesised that stress
is transmitted through the epidermis to
the deeper tissues, which in turn stimulates
the release of inflammatory cytokines in
both the dermal and epidermal tissues.
This inflammatory process triggers the
rapid transit time of keratinocytes coupled
with delayed differentiation of the cells.The
cells therefore journey upwards through
the layers of the epidermis without having
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fully differentiated, the consequences of
which render the structures immature
and therefore biochemically and
structurally compromised. Examples of
this include incomplete degradation of
the desmosomes and abnormal lipid
bilayer formation. Changes in the nature
of these adhesion factors lead to altered
corneocyte cohesion and desquamation
leading to the thickening of the SC. It is at
this point that the clinical presentation of
callus becomes apparent.The increased
thickness of the SC will lower the water
content of the skin and the callus becomes
dessicated and rigid.The increased rigidity
of the skin makes it less pliable in response
to physical stresses therefore bringing
the process full circle and causing more
inflammation, and so on (Thomas et al,
1985).
A corn comprises hard SC similar
to that found in callus tissue (Figure
4) but instead of having a plaque type
architecture it develops into a cone shape
where the tip of the cone is indented into
the skin. This explains why corns can often
be more painful than callus, particularly
when walking. It is not uncommon for
individuals to alter their gait patterns as a
protective measure to prevent pain. This
in turn can lead to strain on other lower
limb structures.
Management of corns and callus
There is no one definite treatment for
calluses and corns and the scientific
evidence for the efficacy of treatments
is virtually non-existent. However, from
a clinical practice point of view, the
healthcare practitioner implements
treatment plans with the following points
in mind: 1) to provide symptomatic relief,
2) to determine the mechanical causes,
3) to prevent the condition from getting
worse, and 4) to decide on a treatment
modality or regime that includes padding
and/or modification of footwear where
appropriate. If the cause of the callus
formation is known, then this should be
tackled in the first instance (Figure 5).
Podiatric management
The first line of treatment in order to
reduce pain and discomfort is the removal
of the callus and enucleation of the corns
using a surgical scalpel. Post-debridement,
the application of adhesive padding often
38
adds to the pain relief by cushioning the
area (open cell foam) or redirecting the
load away from the area of the lesion
(semi-compressed felt with a cavity
corresponding to the area of the lesion). If
increased shear stresses are the suspected
cause, pads made from polymers or
silicone-based gels prove to be effective in
protecting the skin.This is particularly the
case for lesions on the top of the toes.
A degree of home care is often
recommended to reduce the rate of
regrowth of the hyperkeratotic tissue.
Figure 6 summarises the types of topical
treatments that are used for both
treatment and prevention by podiatrists,
or by the patients themselves.
Outcome measures for the efficacy of callus
and corn therapies
Currently, the clinical outcome measures
used to assess the progression and
Footware
(Richards, 1991)
Abnormal foot
pressures
Structural foot
deformity:
bony or soft tissue
Pressure relieving
insoles
(Colagiuri et al, 1995)
Surgery
Advice to the patient:
1. Internal shoe length should
be 1cm longer than the tip of
the first toe.
2. Adequate depth and width
of toe box of the shoe.
3. Insole should be smooth,
with no creases or seams
4. Lace or straps will reduce
the potential of friction and
shear between the foot and
the shoe material.
Figure 5. Causes and treatment of corns and callus.
regression of corns and callus are limited
to pain analogue scales and lesion
surface area measurements. Non-invasive
measurements of the depth of lesions
and the structural change in the skin,
using diagnostic ultrasound, have been
explored, however, due to the dense
nature of hyperkeratotic tissue the image
resolution is poor for corns and callus
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Podiatry-mj-Cjp3.indd 42
Figure 4. Plantar hard corn (heloma durum).
(Hashmi et al, 2006). The use of optical
coherence tomography (OCT) for
general skin assessment is now becoming
more available in dermatology clinics
(Baillie et al, 2011). This non-invasive
method of imaging the superficial layers
of the epidermis has the potential to
produce clear images of corn and callus
tissue before and after treatment. Due
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Callus
Salicylic acid (12.5%) BP*
1. Urea cream (10% to 30%)
(Goldstain, Gurge, 2008)
2. E45 cream (caution: Ianolin
may cause an allergic reaction)
Action
Keratolytic
Keratoplastic
Keratoplastic
Administered by
Podiatrist;
Home care
by patient
Home care
by patient
1. Administered
by podiatrist
2. Home care by patient
Product
Dressings:
1. Hydrocolloid gel pad
2. Polymer gel pad
Corns
1. Salicylic acid (12.5%)
in colloidin BP
2. Salicylic acid (40%)
paste or plaster*
(Farndon et al 2012)
Silver nitrate
(75% or 95%)*
Action
Keratolytic
Caustic
Administered by
Podiatrist.
Home care
by patient
Podiatrist
Product
Dressings:
1. Hydrocolloid gel
pad
2. Polymer gel pad
Surgical removal of
chronic fibrous corns
Electrodessication
(Whinfield, Forster,
1997)
Keratoplastic
Excision
Excision
1. Administered
by podiatrist
2. Home care by patient
Podiatrist
with appropriate
surgical training
Podiatrist
Figure 6. Topical treatments used by podiatrists or patients for the treatment and prevention of corns and callus.
*Patients who are deemed ‘at risk’ of ulceration should not use the caustic and high-potency keratolytic preparations
a
b
Figure 7. OCT image of interdigital corn with overlying callus, a. before treatment and b. after removal with a surgical blade. SC and SS represent Stratum
Corneum and Stratum Spinosum, respectively. Equipment: Michaelson Diagnostics Ltd, UK.
to the clarity of the images produced by
OCT the precise measurement of the
depth of skin lesions can be obtained
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Podiatry-mj-Cjp3.indd 43
(Figure 7). A better understanding
of the physical nature of the SC in
normal and pathological states on the
foot would provide knowledge in two
fundamental areas of the pathology of
hyperkeratosis: 1) understanding the
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a
b
An investigation of protein glycation and
biomechanical properties of plantar epidermis.
Eur J Dermatol 16(1): 23-32
Health and Social Care Information Centre
(2005) www.official-documents.gov.uk/
document/hc0607/hc02/0270/0270.asp
Jones V (1998) Debridement of diabetic foot
lesions. Diabet Foot 1(3): 88-94
c
d
Longhurst B, Allen E, Bristow I (2010) The use
of cyanoacrylates in the management of dry
heel fissures: a preliminary study. Podiatry Now
13(9): 11-15
McKay IA, Leigh IM (1991) Epidermal
cytokines and their roles in cutaneous wound
healing. Br J Dermatol 124(6): 513-518
Figure 8. Magnified images of the surface of hyperkeratosis foot skin before and after treatment.
Figures a and b represent plantar callus before and after removal of the callus with a surgical
blade, respectively, and c and d represent a heel fissure before and after 2 weeks of urea emollient
treatment, respectively. Equipment: Visioscan® Courage and Khazaka, Germany.
predisposing features that place foot
skin at risk of callus and corn formation,
and 2) quantifying the effectiveness of
specific treatment regimes for specific
hyperkeratotic pathologies. Researchers
at the University of Salford (UK) have
made headway in this area by developing
and validating methods of measuring
specific biophysical properties of plantar
foot skin. The non-invasive measurement
devices developed for use on the foot
are available commercially for use in the
cosmetics industry. The capabilities of the
devices include the quantification of skin
surface hydration, viscoelasticity, collagen
organisation within the dermis and skin
surface texture. Figure 8 contains images
of surface texture of plantar callus and
heel fissures before and after treatment.
evidence base for the treatment of
common foot skin pathologies. DN
Repeatability tests of the devices on
normal and pathological foot skin have
proven to be reliable (Wright et al, 2012)
and work is currently underway using
these measures to test for the efficacy of
topical therapies compared to the gold
standard podiatry treatment. These are
the first studies to reliably quantify the
effects of corn, callus and heel fissure
treatments in terms of the structure and
function of the tissues involved. The value
of these methods is far reaching and it is
envisaged that they will be implemented
in clinical practice to monitor the effects
of treatments as well as generating an
Colagiuri S, Marsden LL, Naidu V, Taylor L
(1995) The use of orthotic devices to correct
plantar callus in people with diabetes. Diabetes
Res Clin Pract 28: 29-34
40
Acknowledgements
Michaelson Diagnostics Ltd for the loan
of a VivoSight MultiBeam OCT probe and
use of the images in this article. Reckitt
Benckiser Brands (UK) for funding the
work done at the University of Salford.
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