Diabetic Foot: Recognising Early Warning Signs, Reducing Risks and Utilizing Podiatric Prevention

What lies behind the condition

Diabetic foot syndrome is a complex secondary complication triggered primarily by prolonged hyperglycaemia. Permanently elevated blood glucose levels damage both the peripheral nervous system and the arterial blood supply over the years. Essentially, two main pathological mechanisms are distinguished: diabetic neuropathy and peripheral arterial disease, with a mixed form occurring very frequently.

Diabetic neuropathy affects various fibre systems of the nervous system. In sensorimotor polyneuropathy, the perception of pain, temperature, and touch is gradually lost. This loss of protective sensation means that thermal, chemical, or mechanical stimuli are no longer perceived as signals of impending tissue damage. At the same time, damage to motor nerve fibres leads to atrophy of the small intrinsic foot muscles. The results are characteristic deformities such as claw toes or hammer toes, as well as thinning of the plantar fat pad. Consequently, peak pressure during walking shifts to the metatarsal heads.

Equally significant is autonomic neuropathy, which impairs sweat gland function. The foot loses its natural moisture regulation: the skin becomes extremely dry, brittle, and loses its elasticity. Deep skin cracks, known as rhagades, develop and serve as portals of entry for bacteria. If macroangiopathy is additionally present, namely a narrowing of the large peripheral arteries, the tissue receives an insufficient supply of oxygen and nutrients. Consequently, tissue defects heal extremely poorly.

For medical assessment of the degree of damage, healthcare professionals use established classification systems. The Wagner classification ranges from Grade 0 with intact skin on a foot at risk, to Grade 5 with extensive tissue necrosis of the entire foot. In addition, the Armstrong classification takes the presence of infection and circulatory disorders into account across four stages, A to D. This differentiation is crucial for establishing the precise treatment requirements and the necessity of medical interventions.

Typical signs

The first early warning signs of peripheral neuropathy develop insidiously and are often misinterpreted by affected individuals. Typical sensory deficits include tingling, formication, a numb sensation on the soles of the feet, or burning dysaesthesia, which intensifies particularly during rest periods at night. Altered temperature perception becomes apparent when a foot bath feels comfortably warm even though the water is already hot enough to cause burns.

Circumscribed hyperkeratotic thickenings appear at the weight-bearing zones of the plantar surface. These hyperkeratoses develop as skin reactions to increased shear and pressure forces. The insidious aspect is that tissue haemorrhages or fluid accumulations can form unnoticed beneath the dense calloused layer. Without professional debridement, this pressure in deep tissue leads to aseptic necrosis, which presents as a neuropathic ulcer once it breaks through the skin.

It is important to distinguish the neuropathic presentation from purely arterial circulatory impairment. The purely neuropathic foot is usually warm, pink, and has palpable foot pulses, yet exhibits absent pain perception. By contrast, the ischaemic foot appears cool, pale, or cyanotic. Foot pulses at the dorsalis pedis artery and behind the medial malleolus are weak or absent. Exertional calf pain occurs after walking only short distances.

A short case example illustrates this dynamic. The 68-year-old patient Gerhard M. noticed dark spots in the heel area when removing his socks in the evening. A small pebble had lodged itself in the lining of his work shoe. Because pain perception was entirely absent due to diabetic neuropathy, he walked on the foreign object all day without discomfort. The focal pressure over several hours caused a subcutaneous haematoma under a callus. Only through professional podiatric removal of the hyperkeratosis could the underlying pressure point be relieved and an open wound prevented.

Everyday causes

In daily life, several key factors usually combine to contribute to the development of tissue defects. Wearing ill-fitting footwear represents the most common external cause. Shoes that are too tight, too short, or cut too shallow in the forefoot area generate constant pressure on the toe joints. Hard internal seams or worn insoles also lead to blistering through repetitive friction, which often remains unnoticed for days due to impaired sensation.

Another central risk factor is altered foot geometry combined with abnormal weight distribution. As the transverse and longitudinal arches collapse, the body's line of load shifts. Bony prominences become more pronounced and are left defenceless against the hard counter-pressure of the shoe sole. The skin responds with accelerated keratinisation, which further increases local pressure.

Improper care routines at home also carry significant risks. Trimming toenails with sharp metal scissors or nail clippers easily causes small cuts in the nail fold. If the nail edges are rounded off deep into the lateral sulcus, the regrowing nail can pierce the soft tissue and cause painful, purulent inflammation.

The use of over-the-counter corn plasters or liquid callus removers poses a particular hazard. These preparations often contain highly concentrated salicylic acid, which chemically dissolves keratin. Because the active ingredient does not stop at the hyperkeratotic boundary, it attacks healthy dermis unnoticed in numb skin. Deep chemical burns develop, which subsequently become infected. Equally dangerous are direct heat sources such as heating pads, hot water bottles, or excessively hot foot baths, which can lead to second- or third-degree burns due to the lack of functioning thermoreceptors.

When medical assessment is required

In the presence of changes on the diabetic foot, early medical evaluation is essential to halt the progression of tissue defects. Any break in skin integrity warrants immediate assessment by the attending diabetologist, general practitioner, or a specialised diabetic foot clinic.

Urgent action is required upon the appearance of local signs of inflammation. If areas around a callus or blister become markedly red, warm, or swollen, this indicates a bacterial infection. If redness spreads extensively or if purulent, foul-smelling discharge occurs, immediate infectiological and surgical evaluation is required. Dark, blue-black skin discolourations are also warning signs that indicate necrotic tissue. If systemic symptoms such as fever, chills, or an unexplained deterioration in glycaemic control arise, the situation constitutes a medical emergency.

The medical team determines the need for wound debridement, antibacterial therapy, and pressure-relieving devices such as therapeutic shoes or offloading orthoses. In addition, when indicated, the physician issues a Heilmittelverordnung Muster 13 (official remedy prescription form 13) for a podologische Komplexbehandlung (comprehensive podiatric treatment). Coding is assigned using specific indication codes such as DF1 or DF2, depending on the severity of damage and the presence of sensory loss or vascular deficits.

What podiatric treatment can achieve

Medical podiatry differs fundamentally from purely cosmetic foot care. It is a targeted, medically supportive therapy carried out in accordance with strict hygienic guidelines and medical standards. Every initial treatment begins with a thorough podiatric assessment, which is updated regularly.

As part of the screening-based assessment, the extent of sensory deficits is evaluated. For this purpose, the podiatrist uses the 10-gram Semmes-Weinstein monofilament to determine the loss of protective sensation at defined testing sites on the sole of the foot. Vibration perception is tested using a calibrated Rydel-Seiffer tuning fork at the bony landmarks of the first metatarsophalangeal joint and the malleoli. The Tip-Therm device is used to test the ability to distinguish between warm and cold stimuli. This functional diagnostic workup is complemented by evaluating skin condition, assessing foot deformities, and manual palpation of the foot pulses at the dorsalis pedis and posterior tibial arteries.

The podiatric treatment itself encompasses the professional care of the nail plates and skin. Thickened, dystrophic, or fungal-infected nails are thinned down painlessly to a normal level using specialized rotary diamond burs. Trimming is performed straight across to prevent the nail edges from ingrowing. Ingrown nails without acute purulent infection can be gently corrected through the application of nail braces.

A major focus lies in the painless debridement of hyperkeratoses, calluses, and corns. Sterile scalpel blades and gouges are utilized for this purpose. Hyperkeratotic material is precisely removed layer by layer until resilient, healthy tissue is exposed. This immediately reduces focal pressure on the underlying tissue layers. If toe-related pressure points are present, the podiatrist can fabricate custom pressure- and friction-relieving orthoses made of medical-grade silicone. Treatment and follow-up intervals are determined individually based on the risk profile and typically range from four to six weeks for patients with confirmed neuropathy. A single treatment session generally lasts between 30 and 45 minutes.

What you can do yourself

Daily self-inspection is one of the most effective measures to prevent tissue damage in diabetic foot syndrome. A structured routine enables even the smallest changes to be identified before inflammatory processes develop.

• Daily inspection: Examine your feet every day in good lighting. Use a hand mirror or place a magnifying mirror on the floor to inspect the soles and heels completely. Pay particular attention to redness, blisters, haemorrhages, cracks, or moist areas between the toes.
• Gentle cleaning: Wash your feet daily for a brief period using lukewarm water. The water temperature must always be checked beforehand with a bath thermometer and must not exceed 37 degrees Celsius. Washing should not exceed three minutes to prevent skin maceration.
• Thorough drying: Dry the skin carefully after washing. Use a soft towel and gently pat the skin dry. Ensure meticulously that the spaces between the toes are completely dry, as residual moisture promotes fungal growth.
• Targeted moisturizing: Apply a moisturizing cream foam or ointment daily. Products with a urea content of five to ten percent bind moisture within the stratum corneum and restore elasticity. Avoid applying moisturizer between the toes to prevent maceration.
• Suitable footwear and socks: Feel the inside of your shoes with your hand every time before putting them on. Check for small pebbles, accumulated sand, or creased insoles inside the shoe. Wear seamless socks made of cotton or wool without constricting elastic bands.

Common mistakes

In clinical practice, well-intentioned behaviours frequently emerge that unintentionally increase the risk of severe foot complications. Omission of adequate protective measures is usually based on an underestimated awareness of risk.

• Walking barefoot indoors and outdoors: Walking without sturdy footwear carries major risks, even on carpeted floors. Small foreign objects such as toy bricks, needles, or glass splinters penetrate the insensitive skin effortlessly.
• Use of sharp instruments: Self-management using nail clippers, razor blades, rasps, or corn shavers leads extremely frequently to accidental tissue cuts.
• Use of chemical corn remedies: Over-the-counter tinctures and plasters for hyperkeratoses cause uncontrolled deep chemical burns, creating wounds that are difficult to heal.
• Use of direct heat sources: Applying hot water bottles, grain cushions, or electric blankets to numb feet regularly causes severe thermal injury.
• Neglecting minor lesions: Waiting when inconspicuous pressure points, blisters, or skin cracks appear in the hope of self-healing delays necessary medical care.

Another frequent misconception concerns cold sensations in the feet. Many individuals interpret icy toes purely as a circulatory disorder and attempt to warm their feet with hot baths or heat lamps. However, this is often a neuropathic misinterpretation by damaged nerves. Applying heat to numb skin in these cases leads to deep burns, which require months of treatment due to compromised healing capacity.

Scientific evidence and context

Scientific evidence regarding the prevention and management of diabetic foot syndrome underlines the necessity of structured care protocols. The German National Care Guideline for Type 2 Diabetes (Nationale VersorgungsLeitlinie Typ-2-Diabetes) emphasizes that regular podiatric monitoring and treatment can significantly reduce the incidence of primary and secondary ulcerations [1]. The combination of professional debridement, pedorthic footwear management, and diabetological care reduces amputation rates in high-risk patients by up to 80 percent [2].

The International Working Group on the Diabetic Foot (IWGDF) clarifies in its global guidelines that continuous screening across risk categories A to C represents the most effective measure to prevent recurrent wound defects [3]. Studies demonstrate that the protective pain reflex is no longer functional once 10-gram monofilament perception is lost, which is why these patients must be assigned close monitoring intervals [4].

Current clinical investigations also demonstrate that regular removal of hyperkeratoses by qualified podiatrists reduces focally elevated peak tissue pressure by more than 30 percent [5]. This pressure reduction is the decisive physical factor in minimizing the risk of subkeratotic haemorrhage and maintaining long-term tissue integrity.

Treatment in Memmingen

For patients in the Unterallgäu, Upper Swabia, and Allgäu regions, FREITAG® Podologie GmbH in Memmingen provides a qualified centre for preventive and therapeutic foot care. In the modern practice facilities at Kempterstr. 25, 87700 Memmingen, the practice team under the direction of Helga Maria Freitag conducts comprehensive, screening-based assessments. As a state-recognised podiatrist and sektorale Heilpraktikerin für Podologie (sectoral practitioner of podiatry), she possesses the technical expertise to detect high-risk skin and nail changes at an early stage and tailor treatment protocols precisely to individual findings.

As part of the podologische Komplexbehandlung (comprehensive podiatric treatment), all measures are carried out in accordance with the strictest hygiene standards. When an appropriate medical prescription is present, billing is processed directly with statutory and private health insurance funds. Thanks to a tranquil practice environment and a central location, structured and reliable preventive care is assured for patients from across the entire region.