Chapter 7: Foot Problems

The diagnosis of localised, tender lumps on the sole of the foot can be difficult. The differential diagnosis of callus, corn and wart is aided by an understanding of their morphology and the effect of paring these lumps (Table 7.1).

A callus (Fig. 7.1) is simply a localised area of hyperkeratosis related to some form of pressure and friction.

A corn (Fig. 7.2) is a small, localised, conical thickening, which may resemble a plantar wart but which gives a different appearance on paring.

A wart (Fig. 7.3) is more invasive, and paring reveals multiple small, pinpoint bleeding spots.

There are many treatments for this common and at times frustrating problem. A good rule is to avoid scalpel excision, diathermy or electrocautery because of the problem of scarring. One of the problems with the removal of plantar warts is the ‘iceberg’ configuration (Fig. 7.4) and not all may be removed. Pare the wart with a scalpel or file with a pumice stone or emery board prior to treatment.

Liquid nitrogen

1. Pare wart.

2. Apply liquid nitrogen (use double freeze–thaw cycle).

3. Repeat every 2 weeks until resolved.

Can be painful and results are often disappointing.

Topical chemotherapy

1. Pare wart (particularly in children).

2. Apply Upton’s paste to wart each night and cover.

3. Review as necessary.

(Upton’s paste comprises trichloroacetic acid 1 part, salicylic acid 6 parts, glycerine to a stiff paste.)

Topical chemotherapy and liquid nitrogen

1. Pare wart (a 21-gauge blade is recommended).

2. Apply paste of 70% salicylic acid in raw linseed oil. This can be done by placing a corn pad over the wart and filling the central hole with the paste. Protect the surrounding skin with nail polish (acetone) or Sleek tape.

3. Occlude for 1 week.

4. Pare on review, then curette or apply liquid nitrogen and review.

Other combo methods

• 70% salicylic acid in linseed oil paste for 2 to 3 days followed by 40% salicylic acid in white soft paraffin 2 to 3 times weekly.

Curettage under local anaesthetic

1. Pare the wart vigorously to reveal the extent of the wart.

2. Thoroughly curette the entire wart with a dermal curette.

3. Hold the foot dependent over a kidney dish until the bleeding stops (this always stops spontaneously and avoids a bleed later on the way home).

4. Apply 50% trichloroacetic acid to the base.

Occlusion with topical chemotherapy

A method of using salicylic acid in a paste for the treatment of plantar warts is described here.

Equipment

You will need:

• 2.5 cm (width) elastic adhesive tape

• 30% salicylic acid in Lassar’s paste. (Ask the chemist to prepare a thick paste, like plasticine.)

(Lassar’s paste comprises zinc oxide, starch and salicylic acid, dispersed in white petrolatum.)

Method

1. Cut two lengths of adhesive tape, one about 5 cm and the other shorter.

2. Fold the shorter length in half, sticky side out (Fig. 7.5a).

3. Cut a half circle at the folded edge to accommodate the wart.

4. Press this tape down so that the hole is over the wart.

5. Roll a small ball of the paste in the palm of the hand and then press it into the wart.

6. Cover the tape, paste and wart with the longer strip of tape (Fig. 7.5b).

7. This paste should be reapplied twice daily for 2 to 3 weeks.

8. The reapplication is achieved by peeling back the longer strip to expose the wart, adding a fresh ball of paste to the wart weekly and then recovering with the upper tape.

The plantar wart invariably crumbles and vanishes. If the wart is particularly stubborn, 50% salicylic acid can be used. For finger warts use 20% salicylic acid. This method should not be used for vaginal, penile or eyelid warts.

Alternative chemicals

• Formalin: Wearing gloves, syringe a small amount out of a specimen jar and place in a test tube. Upturn the test tube on the wart and leave in place for 5 minutes. Repeat daily and pare the wart weekly. Formalin is toxic: use with caution and keep in a locked cabinet.

• Salicylic acid 17%, lactic acid 17% in collodion (Dermatech Wart Treatment).

• Paste of trichloroacetic acid 1 part, salicylic acid 6 parts, glycerine 20 gm (Upton’s paste).

• Salicylic acid, lactic acid in collodion (Duofilm™).

• DCP ointment (see Chapter 3).

Poultice of aspirin and tea tree oil¹

Method

1. Place a non-effervescent 125–300 mg soluble aspirin tablet on the centre of the wart and dampen it with 15% tea tree oil in alcohol.

2. Cover with a cotton pad and tape firmly with Micropore™. Allow it to get wet to encourage dissolution.

3. After one week remove the dressing and debride or curette the friable slough.

4. Repeat if necessary.

Dr Scholl’s corn pads

Apply pad with 40% salicylic acid daily for 2 days then according to response.

Simple (and unusual) treatments

The banana skin method

1. Cut a small disk of banana skin to cover the wart.

2. Apply the inner soft surface of the banana skin to the wart and cover with tape.

3. Perform this daily for a few weeks or as long as necessary.

The citric and acetic acid method

Soak pieces of lemon rind in vinegar for 3 to 4 days and then apply a small piece to the wart each day and cover with tape. The crumbling slough can usually be curetted out after 2 to 3 weeks.

• No treatment is required if asymptomatic.

• Remove the cause.

• Proper footwear is essential—wide shoes and cushioned pads over the ball of the foot.

• Provide paring with a scalpel blade (the most effective) or file with callus files.

• If severe, daily applications of 10% salicylic acid in soft paraffin or Eulactol^® Heel Balm with regular paring.

Paring method

Hold a no. 10 scalpel blade with the bevel almost parallel to the skin and shave the lines of any cracks with small, swift strokes (Fig. 7.6). Scrape along the lines of any cracks, not into them. Be careful not to draw blood.

Hard corns, e.g. outside of toes

• Remove the cause of friction and use wide shoes.

• Soften the corn with daily applications of 15% salicylic acid in collodion and then pare when soft.

An alternative is to apply commercial medicated disks (e.g. 40% salicylic acid) on a daily basis for about 4 days, then pare.

Soft corns in webbing of toes

For soft corns between the toes (usually the last toe-web), treat in the same way, but keep the toe-webs separated with lamb’s wool at all times, or use cigarette filter tips (these can be purchased at tobacco stores) separately and dust with a foot powder.

Method 1

• Soak the feet for 30 minutes in warm water containing an oil such as Alpha-Keri or Derma Oil™.

• Pat dry, then apply a cream such as Nutraplus (10% urea) or Eulactol^® Heel Balm.

• Apply twice daily and keep covered at night e.g. with cotton socks.

Method 2

Consider applying medical skin glue, e.g. Histoacryl^® or even superglue, to neatly fill a dry crack and leave, with review in 4 days. This provides instant pain relief and often good healing.

Plantar fasciitis is a very common and surprisingly debilitating condition that may take 12 to 36 months (typically 2 years) to resolve spontaneously.

Features

• Pain:

  • under the heel (about 5 cm from end of heel)

  • can be diffuse over heel

  • when first step out of bed

  • relieved by walking around after shower

  • increasing towards the end of the day

  • worse after sitting

  • felt as a severe throbbing while sitting

• Minimal signs

• X-ray may reveal a calcaneal spur

Patient advice

• Avoid standing for long periods if possible.

• Rest from long walks and running.

• Try to cope without injections.

• Keep the heel ‘cushioned’ by wearing comfortable shoes and/or inserts in shoes.

• Surgery is rarely required and is not usually recommended. Excision of the calcaneal spur is advised against.

Footwear and insoles

Obtain good, comfortable shoes with a cushioned sole (e.g. Florsheim ‘Comfortech’; sporting ‘runners’).

Examples of orthotic pads:

• Viscospot^® orthotic

• Rose insole

• an insole tailored by your podiatrist

• a pad made from sponge or sorbo rubber placed inside the shoe to raise the heel about 1 cm. A hole corresponding to the tender area can be cut out of the pad to avoid direct contact with the sole (Fig. 7.7).

Hydrotherapy

The following tips have proved very useful for patients.

Hot and cold water treatment

The patient places the affected foot in a small bath of very hot water and then a small bath of cold water for 20 to 30 seconds each time. This is continued on an alternating basis for 15 minutes—preferably twice a day and best before retiring at night.

Therapeutic foot massage

Commercial electrical foot hydro-massagers are available at low cost and are recommended for patients with plantar fasciitis.

Exercises^3,4

Most foot surgeons now recommend regular stretching exercises as the basis of effective treatment. The aim is to allow the plantar fascia to heal at its ‘natural length’. Stretching should be performed at least 3 times or more if manageable a day. It is recommended to perform at least 2 of the following exercises.

Exercise 1: sitting position stretch

1. Sit on a bed with both legs straight out in front of you and your hands on your knees.

2. Using a rope towel or cord looped around the foot, pull the foot back and point your toes towards your head, bending the foot upwards at the ankle (Fig. 7.8a). The more effort you put into the motion, the better the stretch will be.

3. Hold the position for as long as possible (at least 30 seconds). Repeat several times.

Exercise 2

1. Stand on a stair, with the ball of your foot (or feet) on the edge of the stair, and keep your knees straight.

2. Holding the rails for balance, let your heels gently drop as you count to 20. Do not bounce (Fig. 7.8b). You should be relaxed, and no active muscle contraction should be necessary in your leg.

3. Lift your heels and count to 10.

4. Repeat the cycle twice. You will feel tightness both in the sole or heel of the foot, and at the back of the leg (as the Achilles tendon is also stretched).

Exercise 3

1. Stand against a solid wall with your painful foot behind you and the other foot closer to the wall (Fig. 7.8c).

2. Point the toes of the affected foot towards the heel of the front foot. Keep the knee of the painful foot straight and the painful heel on the floor.

3. Bend the front knee forward—you will feel the Achilles tendon in the painful foot grow tight.

4. Count to 20, then relax for a count of 10.

5. Repeat the cycle twice.

6. Change over the position of each foot and repeat the program to stretch the opposite Achilles tendon.

Exercise 4

You must be wearing flexible sole shoes for this exercise.

1. Stand against the wall with your good foot behind you and the painful foot jammed into the juncture of the wall and floor (Fig. 7.8d).

2. Bend the knee of the front leg, which will bring it towards the wall. You will feel that both the Achilles tendon and the tissue on the sole of the foot (plantar fascia) are being stretched by this exercise.

3. Count to 20, then relax for a count of 10.

4. Repeat the cycle twice.

5. Change over the position of each foot and repeat the program to stretch the opposite side.

Strapping for plantar fasciitis

Strapping of the affected foot can bring symptomatic relief for the pain of plantar fasciitis. A few strapping techniques can be used but the principle is to prevent excessive pronation, create a degree of inversion and reduce tension on the origin of the plantar fascia by compressing the heel. Use non-stretch sticking tape about 3–4 cm wide.

Method

• Start with the tape on the lateral side of the dorsum of the foot (Fig. 7.9a).

• Run the tape in a figure-of-eight configuration to include the sides of the heel but squeeze the heel from the sides to make a ‘pad’ immediately before applying and fixing the tape.

• Repeat twice (Fig. 7.9b).

If reinforcement is desired, a U-shaped strip of tape can be applied to the sides of the foot—from the neck of the metatarsals on one side to the other. Also, a strip of holding tape can encircle the foot.

Other tips

Manual massage

Massage the sole of the foot over a wooden foot massager, a glass bottle filled with water, or even a golf ball for 5 minutes, preferably 3 times daily.

Course of NSAIDs

It is worthwhile to conduct a trial of a 3-week course of NSAIDs during the time when there is most pain (about 4 to 7 weeks after the problem commences). It can be continued if there is a good response.

Injection

An injection of corticosteroid mixed with local anaesthetic can be very effective during the period of severe discomfort. (See Fig. 3.26.) The relief usually lasts for 2 to 4 weeks during this difficult period. However, injections are generally avoided.