Fungal infections of the foot & lower limb

Fungal infections of the skin & nail may be a primary condition, secondary to bacterial infection or associated with a systemic condition, eg. Diabetes mellitus.

 The dark, warm, moist environment found in most shod feet is an ideal breeding ground for fungi. The condition can be caused by a dermatophyte infection, eg. Trichophyton, or a yeast infection, eg. Candida albicans, of the keratinised layer of the epidermis.

Tinea Pedis  (athlete’s foot)  Tinea Pedis is a fungal infection of the skin of the foot. It is usually caused by a yeast infection breeding in warm, moist & occluded areas including sweaty footwear, public showers & baths as well as communal areas including saunas, spas & steam rooms.

This condition may manifest on the feet in three ways:

• Inter-digital skin may appear macerated (white) & soggy. There may be an unpleasant odour. Moist fissures may be present.
• Patches of skin, or all the skin of the foot, may be affected by recurrent vesicular eruptions. The area affected is itchy & red in colour. The instep is a common site for this type of tinea
• The soles of the foot may appear dry & scaly & the patient will often complain of itchiness. This is usually due to a trichophyton rubrum infection.

Symptoms common to all types of Tinea Pedis include:

• Redness, itchiness & dryness of the skin of the foot
• Inter-digital maceration & fissuring
• Dry, cracked heels & vesicular eruptions
• Pressure lesions (corns & callous) on the plantar aspect of the foot

When the dermis is exposed the condition is painful & bacterial infection may develop. If the entire plantar surface of the foot is affected, the skin is mechanically weak, sore & fissures can develop. Fungal infections of the foot & lower limb can provoke a secondary eruption of the hands.

Onychomycosis  (fungal infection of the nail) This condition appears in the nail & can be classified into four distinctive types:

• Distal and lateral subungual is the most common type of dermatophyte onychomycosis. The distal end & side of the nail are affected.
• Proximal subungual is caused by a yeast infection & arises from the proximal part of the nail. It often occurs secondary to chronic paronychia.
• Superficial white onychomycosis results in the nail plate appearing white. The nail is affected distal to proximal. The condition is due to Trichophyton mentagrophytes & is relatively uncommon.
• Total dystrophic: In this type the appearance & texture of the whole nail is affected. It may arise as a consequence of any of the above types.

Symptoms common to all types of onychomychosis include:

• White discolouration of the nail plate
• Pain &  tenderness upon palpation of the toe
• Thickening, lifting & eventual detachment of the nail plate from the toe
• A weakened, thinned-out nail which tends to crumble when cut
• Ingrown toenails
• Yellowish-white vertical striations extending proximally down the nail plate

Treatment:

• All fungal infections of the foot & lower limb need to be treated by a form of an anti-fungal agent recommended to you by your podiatrist
• Reduce any excess moisture in your footwear by allowing them to dry in direct sunlight on the clothes line or back verandah
• Limit excess sweating by wearing natural-fibred socks such as cotton or wool
• Wearing of open-toed footwear
• Proper drying of the foot after showering especially in-between the toes
• Wearing footwear in communal showers, pools etc. (thongs, booties)

See your Podiatrist for assistance