Foot Skin Problems

Essentials

• Ringworm is a common fungal infection of the skin which may have various clinical pictures when occurring on the feet (tinea pedis or athlete's foot); fungal samples should be taken whenever there are foot skin problems.
• People with diabetes often have foot problems; these should be screened for and treated at an early stage.
• Remember the possibility of irritant contact dermatitis (sweating and mechanical stimuli), allergic contact eczema (shoes, topical antifungal products, skin care products, etc.) and stasis dermatitis (swelling of the feet, venous insufficiency).
• It is important to examine other areas (hands, particularly) in addition to the feet because diagnostic clues may be found there.

Diagnosis

• Good history taking and clinical examination form the cornerstones of correct diagnosis.
• Is there any history of skin disorders? Is there a family history of psoriasis or atopic eczema, for example?
• In patients with diabetes there may be various skin problems, of which chronic, slow-healing ulcers developing after even mild injury are the most common.
• Might the skin problem be due to irritants (e.g. sweating or mechanical factors)?
• Are there any contact allergies or has the patient reacted to a topical treatment (e.g. ointments or wound care products)?
• Previous treatmen
  • Particularly if fungal samples are to be taken, any antifungal medication must be withdrawn a sufficiently long time before sampling Dermatomycoses.
• Does the patient have swollen feet or a history of venous insufficiency?
• Are the lesions itchy (atopic eczema, allergic contact dermatitis)?
• Does the patient have pain or general symptoms (infections)? Erysipelas

The most common dermatological causes

• Atopic eczema Atopic Eczema (Atopic Dermatitis) in Adults, such as atopic winter foot; in children and adolescents juvenile plantar dermatosis (picture )
• Irritant contact dermatitis: due to sweating and/or mechanical stimuli Irritant Contact Dermatitis
• Ringworm: various types Dermatomycoses
  • Ringworm on the foot and between the toes
  • Moccasin-type tinea pedis on the sole of the foot
  • Often asymmetric; can be unilateral, for example
  • May also appear as vesicles with emphasized margins.
• Nummular eczema Nummular Dermatitis (picture ): mainly on the legs but usually also in other places, such as the back
• Neurodermatitis (picture ): caused by a vicious circle of itching and scratching; usually on the tops of the feet, ankles or legs
• Stasis dermatitis (picture ) and skin problems due to venous insufficiency in the lower limbs Leg Oedema
• Allergic contact dermatitis Allergic Contact Dermatitis: acute rash
  • Has contact allergy been diagnosed? Cosmetics or skin care products?
• Scabies Scabies: papules, scratch marks and burrows often particularly on the sides of the legs; skin lesions and itching always also present in other skin areas
• Intrinsic eczemas, such as chronic hyperkeratotic eczema, usually also on the palms; normally symmetric, typically on the plantar arches
• Psoriasis Psoriasis
  • Psoriasis on the soles of the feet (picture )
  • Often also occurs in other areas, such as the palms or the scalp.
  • Psoriatic lesions are typically symmetric, with thick scale, the clinical picture is stable, and there are no vesicles.
• Palmoplantar pustulosis
  • Acutely appearing pustules on the soles of the feet and on the palms
  • Intermittent severe scaling, often primarily on the plantar arches
  • Patients often smokers

Causes related to circulatory problems and diabetes

• Diabetic foot; neuropathic and ischaemic wounds Treatment of the Diabetic Foot
• Charcot's foot
  • A relatively acute clinical state occurring in non-ischaemic feet in people with diabetes: swelling, mild pain, heat and sometimes erythema in the foot area
  • Inflammatory parameters are normally not elevated Treatment of the Diabetic Foot.
• Lesions and wounds caused by venous insufficiency in the lower limbs: varicosities, swelling, stasis dermatitis, pigmentation, lipodermatosclerosis, hardening of the skin, atrophie blanche, superficial phlebitis or ulcers Venous Insufficiency of the Lower Limbs
• Foot problems due to arteriosclerosis: necrotic ulcers on toes and feet, cold feet and cold skin, atrophic, shiny skin, scaling, pigmentation, loss of skin hair, nail lesions Lower Limb Ischaemia
• Pressure sores (decubitus): at first blueish red, patchy erythema, often a blister filled with blood or tissue fluid, and subsequent ulceration Prevention and Treatment of Pressure Ulcers

Infections

• Erysipelas or cellulitis, most often on a lower limb Erysipelas
• Secondary infection of a foot ulcer (erythema around the ulcer, pain getting worse, elevated inflammatory parameters)
• Diabetic foot infection (even small injuries may heal poorly and slowly) and osteitis in deeper ulcers Treatment of the Diabetic Foot

Other common skin problems

• Calluses (picture ): often caused by ill-fitting footwear or malposition; for example, calluses on the ball of the foot due to the plantar arch descending with age
• Traction vesicles: caused by mechanical irritation
• Warts Warts (Verruca Vulgaris) (picture )
• Paronychia Paronychia and Ingrown Toenail
• Piezogenic papules (picture ): small fatty herniations on the heels and edges of the feet
• Chilblains (picture ): usually on toes but may also occur elsewhere on the feet; painful lumps covered by blueish red, patchy erythema
• Pitted keratolysis (picture ): pitting on the soles of the feet, associated with sweating
• Plantar xerosis (picture ): thickening and fissures of the corneal layer of the epidermis on the soles of the feet and heels, in particular; often hereditary
• Gout Gout and Pseudogout
  • The typical sign is acute erythematous, severely painful inflammation of the metatarsophalangeal joint of the big toe the night after exposure to cold or physical exertion or a meal high in purines, for example.

Rarer skin problems

• Hand-foot-and-mouth disease Enterovirus Infections (picture ): aphthoid lesions on the palms and soles of the feet and in the mouth
• Recurrent scaling of the soles of the feet, or exfoliative keratolysis (dyshidrosis lamellosa sicca): usually in the summertime; patchy scaling of the palms, too; probably associated with increased sweating
• Granuloma annulare (picture ): usually on the neck or feet, not scaly, asymptomatic or with mild symptoms
• Pigmented purpura (picture ), such as lichen aureus (picture ), small rust-coloured petechiae usually on the legs and feet
• Skin symptoms of systemic rheumatic diseases or vasculitis, such as urticarial vasculitis (picture ), leucocytoclastic purpura (picture ), leucocytoclastic vasculitis, vasculitic ulcer on a toe, erythema induratum (nodular vasculitis; picture ), Henoch-Schönlein purpura (pictures ).
• Congenital keratoderma (group of diseases; congenital thick hyperkeratosis, usually also on hands)

Workup

• Samples for microscopy and fungal culture should be taken without much hesitation from scaly foot dermatitis.
• Rapid methods based on nucleic acid amplification are also available. The dermatophyte nucleic acid test identifies the most common dermatophytes. The indications for use in tinea pedis are not yet established and the diagnostic benefits are unclear.
• CRP and basic blood count with platelet count if erysipelas is suspected
• Fasting glucose and oral glucose tolerance test, as necessary, if diabetes is suspected
• Examination of diabetic foot; inspection and monofilament test Treatment of the Diabetic Foot
• Examination of circulation in the lower limbs (ABIs, and Doppler ultrasonography, as necessary) Lower Limb Ischaemia
• Epicutaneous tests may be indicated if allergic contact dermatitis is suspected.
• Skin biopsy and histological examinations, as necessary, especially if there is a suspicion of a malignant skin change (keep in mind, however, the poor healing of biopsy wounds on feet and legs).

Treatment

• Causal treatment, if possible (such as antifungal medication for ringworm, avoidance of the causative factor in patients with allergic contact dermatitis)
• For ringworm between the toes, it is often sufficient to use a topical antifungal preparation for 2-4 weeks. For moccasin-type tinea pedis on the sole of the foot or ringworm that has spread to the top of the foot, systemic antifungal treatment is often needed in addition to topical treatment Oral Treatments for Fungal Infections of the Skin of the Foot: terbinafine 250 mg once daily for 2-4 weeks or itraconazole 200 mg twice daily for 1 week or 100 mg once daily for 2-4 weeks Psoriasis.
• Foot problems in people with diabetes should be screened for and treated early Patient Education for Preventing Diabetic Foot Ulceration Treatment of the Diabetic Foot.
• For eczematous diseases, the treatment of first choice is intermittent mid- or high potency topical glucocorticoids for 2 to 3 weeks at a time.
• For atopic eczema and often for other eczemas, as well, also topical calcineurin inhibitors Topical Tacrolimus for Atopic Dermatitis (tacrolimus and pimecrolimus ointments) can be used.
• Regular use of non-medicated ointments helps in many skin problems of the feet.
• For stasis dermatitis, compression therapy (supportive bandage or gradient compression stockings) Leg Oedema Treatment of Lower Extremity Ulcers and for exacerbations, a mid- or high potency topical glucocorticoid intermittently once or twice daily for 2-4 weeks at a time. At a calm stage, maintenance therapy with mid- or high potency topical glucocorticoids twice a week is often needed for another 1-3 months. Non-medicated ointments should be used on the days between.
• For neurodermatitis and chronic eczematous diseases, intermittent treatment with high to superpotency glucocorticoids is often needed in courses of 4-6 weeks, for example.
• For heel fissures and hyperkeratotic eczemas, treatment reducing thickening of the skin (keratolytic ointments) is needed. Topical treatment with urea or salicylic acid, such as salicylic vaseline ointment (extemporaneous prescription: Rec. Acid. salicyl. 5-10.0 g, Vasel. alb. ad 100.0 g) once or twice daily in courses of 1-2 weeks.
• Painful fissures or rhagades can be painted with lapis once or twice daily for a few days at a time (prescription: Rec. Sol. arg. nitr. 0.5-1.0%) in addition to other topical treatment (non-medicated and keratolytic ointments).
• For palmoplantar pustulosis and psoriasis of the soles of the feet, intermittent treatment with high to superpotency topical glucocorticoid ointments is usually needed in courses of 4-6 weeks, for example, combined with keratolytic topical treatment, as necessary. The treatment can be intensified by covering the skin (cotton socks or plastic film wrapped around the feet for the night). In cases resistant to treatment, light therapy (such as ointment-PUVA treatment) guided by a dermatologist and/or oral treatment (retinoids, immunosuppressive medication) should be used.

Specialist consultation

• In severe foot skin problems and ones that are resistant to treatment (e.g. severe intrinsic eczemas, psoriasis, palmoplantar pustulosis), a dermatologist should be consulted.
• Epicutaneous tests should be performed if allergic contact dermatitis is suspected.
• If a circulatory problem is suspected or the case is resistant to treatment, a vascular surgeon should be consulted (examination of circulation in the lower limbs).
• Complicated foot infections in people with diabetes often require hospital treatment Treatment of the Diabetic Foot.

Pictures