Common Foot Disorder

Question 1

Describe the pathophysiology of corns and calluses

Answer 1

Normally, the rate of mitotic division in basal cell layer is the same as the rate of surface cellular desquamination (complete replacement is 1 month)
During corn or callus development, friction and pressure increase mitotic activity of the basal cell layer, leading to the migration of maturing cells through the prickle cell and granular skin layers. This results in hyperkeratosis

Question 2

What factors contribute to corns and calluses?

Answer 2

Friction due to loos or tight fitting shoes
Structural biomechanical problems
Not wearing socks with shoes or wearing ill fitting socks
Walking barefoot
Weight gain
Secondary condition (plantar warts)

Question 3

What is a corn?

Answer 3

Clavus
Small raised, sharply demarcated, hyperkeratotic lesion
Central core/cone (radix) which is triangular shaped and points inward (hard corns)
Soft (heloma molle), hard (heloma durum) or plantar

Question 4

What are the signs and symptoms of a hard corn?

Answer 4

Well defined
Yellowish-grey colour
Few mm to 1 cm or more in diameter
Shiny, dry and polished with a loss of normal skin pattern
Central core visible
Pain
Affects skin directly overlying bony prominence or may occur on soles of feet
Usually occurs on the surface of the fourth or fifth toes

Question 5

What are the signs and symptoms of a soft corn?

Answer 5

Whitish thickening of skin
Soft in appearance
Usually found on webs between fourth and fifth toes
May be painful
Often confused with athlete's foot

Question 6

What is a plantar corn?

Answer 6

A corn on the plantar surface of the foot that causes pain on ambulation
May be confused with a plantar wart

Question 7

What is a callus?

Answer 7

Callosity or tyloma
Superficial patches of hornified epidermis
No central core

Question 8

What are the signs and symptoms of a callus?

Answer 8

Yellow-white
Normal skin patter, no central core
Borders are not well defined
Few mm to several cm in diameter
Slightly elevated
Found on areas where the upper layers of skin are naturally thick (i.e., soles of feet, especially on the heel or ball of the foot)

Question 9

Describe the pathophysiology of a plantar wart

Answer 9

HPV enters the skin through small cut or abrasion
It infects the upper epidermis and causes squamous epithelial cells to proliferate
It can remain latent or cause subclinical infection (there’s an infection but it can’t be seen)

Question 10

What is a plantar wart?

Answer 10

Common viral infection of the skin and mucous membrane
Benign tumour caused by HPV
Incubation period is between initial infection to warty lesion varies between 1 and 8 months
Warts are not permanent (they spontaneously clear between 6 months and 5 years)

Question 11

If plantar warts spontaneously clear, why is it important to treat them?

Answer 11

They can spread
They are unsightly
They can be painful and restrict activities
They have the potential to transform into malignant lesions

Question 12

What are the signs and symptoms of plantar warts?

Answer 12

They can occur on the sole of the foot, sole of the heel, great toe, head of metatarsal bone and ball
They are circular lesion with wart in the centre
The surface is rough, greyish-brown and friable surrounded by skin that is thick and heaped
Normal patter of skin is interrupted
Thrombosed capillaries appear as black dots in the centre of the lesion or as pin point bleeding sometimes described as seeds
Singly or in clusters
Usually painless unless direct pressure is applied

Question 13

When completing differential diagnosis of common foot disorders, what other conditions should be considered?

Answer 13

Hard corn: callus, plantar wart
Soft corn: tinea pedis
Callus: corn, plantar wart
Wart: callus, corn, squamous cell carcinoma

Question 14

What are the goals of therapy for corns and calluses?

Answer 14

To remove the corns and calluses
To avoid and prevent complications
To prevent recurrence

Question 15

What are pharmacological treatment options for corns and calluses?

Answer 15

Salicylic acid is the first line treatment

For self treatment use: plaster vehicle (12-40%), collodion vehicle (12-17.6%)

Question 16

Compare SA dosage forms used to treat corns and calluses

Answer 16

SA collodion: proxylin and various volatile solvents, such as ether, acetone and alcohol or a plasticizer (castor oil. Concentration: 17-17.6%
SA plasters/disk/pads: a uniform or semisolid adhesive mixture of SA in a suitable base which is spread on appropriate back material. Concentration: 40%

Question 17

What are the advantages of SA collodion?

Answer 17

Forms film which prevents moisture loss
Usually easiest to apply for patent
Less apt to run onto other areas of skin

Question 18

What are the disadvantages of SA collodion?

Answer 18

Takes longer to resolve
Flammable and volatile
Occlusive nature allows systemic absorption of drug
More irritating than other formulations

Question 19

What are the advantages of SA plasters/disks/pads?

Answer 19

Provides direct and prolonged contact with skin
Plasters may be cut to fit size of lesion
Disks or pads are more convenient
Easy to apply

Question 20

What are the disadvantages of SA plasters/disks/pads?

Answer 20

Patient may be sensitive to adhesive

Question 21

When should collodions be used? What’s the duration of treatment?

Answer 21

More useful in the treatment of soft corns rather than calluses
Hard corns and calluses: up to 14 days or earlier
Soft corns: 3-6 days

Question 22

For what should plasters, disks and pads be used? For who long?

Answer 22

Hard corns and calluses are most easily treated with plasters
Maximum of 5 treatments over a 2 week period
1 treatment is a maximum of 48 hours at a time

Question 23

How are collodions used?

Answer 23

Soak foot for 5 minutes, dry foot and apply once or twice daily
Apply 1 drop at a time until area is well covered
Allows drops to dry and harden
Do not let adjacent areas of skin come in contact with drug
Periodically soak foot in warm water and remove macerated skin

Question 24

How are plasters, disk and pads used?

Answer 24

Soak foot for 5 minutes, dry and apply every 48 hours
If using plaster, trim plaster to follow controls of the lesion
Apply and cover with adhesive tape
If using disk/pad, apply appropriately sized on area and cover
Remove within 48 hours
Soak in warm water and remove macerated skin

Question 25

What are non-pharmacological treatment options for corns and calluses?

Answer 25

Eliminate the cause of the condition Soak affected area daily throughout treatment for 5-10 minutes in warm water and gently remove dead tissue (avoid use of sharp knives and razors, gently use a pumice stone or callus file) To relieve pressure, a foam or cushioned pad with an opening can be used for up to 1 week or longer Change cushion every day Newer cushions consist of soft polymer that adheres to skin without leaving sticky residue Custom pads can be constructed using moleskin or lamb's wool Orthotic devices Keep feet clean and dry Avoid moisturizers between toes Check feet daily

Question 26

How can calluses and corns be prevented?

Answer 26

Maintain moisture balance (neutral unscented moiturizer, hydrating products (e.g., glacial base), anti-dehydration products (e.g., lubriderm)) Remove dead skin

Question 27

Explain how to properly select footwear

Answer 27

Purchase shoes at the end of the day when feet are most swollen Try both shoes on since one foot is larger than the other Buy shoes in proper sizes and ask a trained professional to measure feet Shoes should be fitted when individual is standing First MTP joint should be in the widest part of toe box Base of shoe length on longest toe of your longest foot Make sure toes do not bump into front of shoe Match shoe to activity Heel should fit snuggly (avoid heels over 1.5 inches) If patient plans to wear orthotics in shoe, orthotics should be worn during fitting Once shoe size is determined, choose a shoe shaped to match shape of foot If patient is physically active, make sure shoe's mid-sole provides adequate support and cushioning Lace-up shoes are best Shoes with a wide toe box and lower heel help to prevent toe crowding Shoes with thicker soles provide cushioning

Question 28

What are the monitoring parameters for corns and calluses?

Answer 28

Timeframe for improvement: visible improvement in a few days | Timeframe for resolution of the condition: 14 days for hard corn/callus, 3-6 days for soft corn

Question 29

When should a patient see a physician?

Answer 29

Allergic reaction develops Skin irritation develops that was not present before and/or is moderate to severe Skin ulcers develop Any skin irritation or stinging that is bothersome to the patient Infection develops

Question 30

What are the goals of therapy for plantar warts?

Answer 30

Alleviate or prevent pain due to wart Eradicate lesions and prevent their proliferation Prevent recurrence Prevent transmission to other people

Question 31

What are pharmacological treatment options for plantar warts?

Answer 31

Only plantar and common warts are self treatable No single therapy is proven 100% effective Topical SA is first line defence (12-40% in a plaster vehicle, 5-17% in a collondionlike vehicle, 15% in a chary gum-glycol plaster)

Question 32

What are other (second line) pharmacological treatment options for plantar warts?

Answer 32

``` Dimethylether (DME) and propane Duct tape Cryotherapy with liquid nitrogen Cimetidine Lactic acid Formalin (37% formaldehyde) Surgical intervention Hyperthermic treatment CO2 laser therapy ```

Question 33

What is the ingredient, strength and MOA of duoplant ointment

Answer 33

Salicylic acid 25%, formalin 5% and lactic acid 10% SA: keratolytic (removes skin cells infected with HPV and cause inflammation which reduces immune response) Lactic acid: corrisive properties (enhances SA activity) F: antiviral activity and anhydrite action

Question 34

What is the ingredient, strength and MOA of duofilm liquid

Answer 34

Salicylic acid and lactic acid 16.7% SA: keratolytic (removes skin cells infected with HPV and cause inflammation which reduces immune response) Lactic acid: corrisive properties (enhances SA activity)

Question 35

What is the ingredient, strength and MOA of duofilm patch and Scholl one step plantar wart remover pad?

Answer 35

Salicylic acid 40% | SA: keratolytic (removes skin cells infected with HPV and cause inflammation which reduces immune response)

Question 36

What are the ingredient and strengths of Compound W liquid, Solver Plus liquid and Wart Remover gel?

Answer 36

Compound W liquid: SA 20% Soluver Plus liquid: SA 27% Wart Remover gel: SA 17%

Question 37

What is the ingredient, strength and MOA of canthacure and cantharone

Answer 37

Canthardin 0.7% liquid | Vesicant which causes a blister to forma and wart become necrotic

Question 38

What is the ingredient and MOA of Compound W Freeze Off and Wartner Plantar Warts

Answer 38

DME and propane | Freezes wart and causes a blister to form under it; wart fall of 10-14 days after treatment

Question 39

What are the directions for SA 5-17% in collodion vehicle?

Answer 39

Apply 1 drop at a time until wart is covered. If SA touches healthy skin, wash off with soap and water Use once daily to BID for max 12 weeks

Question 40

What are the directions for SA 40% plaster and disk?

Answer 40

Tram plaster to fit wart; apply plaster and cover with tape Disk: choose best size, apply and cover disk with pad Use q48h for max 12 weeks

Question 41

What are the directions for SA 15% in karaya gum glycol vehicle?

Answer 41

Apply hs for 8 hours; repeat procedure every 24 hours for a max of 12 weeks

Question 42

What are the directions for Wartner and Freezeaway?

Answer 42

Apply to wart for 10-40 seconds; only 1 treatment is usually needed May repeat after 14 days on same wart up to max 3 times for Warnter or 4 times for Freezeaway

Question 43

What are the directions for cantharidin?

Answer 43

Applied by physician (keep lesion occluded for 3-7 days)

Question 44

What are non-pharmacological/prevention treatments for plantar warts?

Answer 44

Avoid walking barefoot and keep feet covered in areas where transmission is more common Change shoes and socks daily Keep feet clean and ry Do not share/touch any possibly infected objects or people Use waterproof tape during treatment Wash hands before and after cleaning feet and caring for wart Do not bite, scratch, poke, probe or cut wart tissue Do not use sharp knives or razors Soak area throughout treatment for 5-10 minutes in warm water and gently remove dead tissue Use good foot hygiene even when the wart is gone

Question 45

How can duct tape be used for plantar warts?

Answer 45

May help with wart removal by causing irritation Apply to wart for 6 days then remove and soak foot Soak area throughout treatment for 5-10 minutes in warm water and gently remove dead tissue (treat for up to 2 months)

Question 46

What are the monitoring parameters for plantar warts?

Answer 46

Timeframe for improvement: 1-2 weeks Timeframe for resolution of the condition: Wart removal may take 4-12 weeks; maximum treatment is 12 weeks. Warts may reappear months after initial treatment

Question 47

When should a patient see a physician for plantar warts?

Answer 47

If the patient develops an allergic reaction after applying the product If the skin becomes damaged and painful, inflamed or infected If any wart persists after 12 weeks of treatment

Question 48

What are side effects of SA for plantar warts?

Answer 48

Redness, burning or irritation

Question 49

What are precautions and contraindications of SA for plantar warts?

Answer 49

Do not use on irritated, infected/broken skin, moles or birthmarks Do not use on face, mouth, nose, anus, genitals or lips Caution if patient takes salicylate, anticoagulants and LMW heparin Apply petroleum jelly to surrounding skin if the patient has poor eyesight/difficulty using product Highly flammable Poisonous if swallowed and/or if inhaled

Question 50

Describe the safety profile of SA in special populations

Answer 50

No human studies on use of topical SA during pregnancy Excretion in breast milk and safety if consumed by nursing infant unknown Caution if patient is under 3 or over 65

Question 51

What are the side effects and precautions of DME/propane products for plantar warts?

Answer 51

Aching, itching, burning, stinging sensation; can cause burns and permanent scars if used on thin skin Safety unknown during pregnancy or lactation Caution if under 4 Caution if patient has DM, PVD or poor circulation Do not use in inaccessible or hard to reach locations Treat only 1 wart at a time on toe with a 2 week interval before treating another wart on same digit Applicators are for single use Flammable

Question 52

What are red flags? (18)

Answer 52

Corns or calluses that indicate an anatomic defect or fault in body with distribution History of DM, PVD or malnourishment Patient is immunocompromised or takes immunosuppressants History of RA and complains of painful metatarsal heads or deviation of great toe Patient has physical or mental impairments that make following product instructions difficult Patient allergic to available options (i.e., SA, ASA, adhesives, etc) Lesion is bleeding or oozing purulent material Lesions extensive or are painful and debilitating Proper self-medication has been tried without success Patients under 3 or over 65 old Pregnancy Skin is red, swollen, inflamed or infected Growth that looks like a mole, birthmark A wart with an unusual appliance Hair growing from lesion Extenstive warts at one site Warts on mucous membranes, face, anus, genitalia or warts under nails Warts are extremely painful and debilitating

Question 53

What is a bunion?

Answer 53

Hallux valgus Deformed big toe joint: joint is angled outward and big toe is angled inward towards other toes 5th toe may develop a bunion (bunionette) Women are 10 times more likely to develop bunions than men

Question 54

Describe the pathophysiology of bunions

Answer 54

Hypertrophy of bone and soft tissues around middle of great toe Great toe becomes abducted and rotated which causes prolonged pressure over first MTP joint May lead to painful inflammation and swelling of bursa over MTP joint, resulting in formation of a bunion

Question 55

What are factors that contribute to formation of a bunion

Answer 55

``` Inherited foot type Faulty foot mechanics Constant abnormal joint motion Shoes that fit improperly and high heels Occupation that puts stress on feet Friction from bone malformations Vigorous exercise Foot injuries RA ```

Question 56

What are the signs and symptoms of a bunion

Answer 56

``` Usually bilateral Bump on outside of edge of big toe Thickening of skin at base of big toe Usually asymptomatic but can become quite red, painful, swollen and tender Restricted movement of big toe ```

Question 57

What should be considered for differential diagnosis of bunion?

Answer 57

Gouty arthritis

Question 58

What are the treatment options for bunions?

Answer 58

Must refer to a physician or podiatrist but in meantime: Remove source of irritation Select properly fitting footwear Modify activity Moleskin, foam or cushioned pads (bathe/thoroughly dry foot then cut into proper shape and apply) Bunion guard (soft polymer gel with no adhesives that can be used up to 3 months) Ice packs ant OTC pain relievers to decrease pain and swelling (acetaminophen and NSAIDs) Splints and orthotic devices If pain is severe: intra-articular corticosteroid injection available by physician Surgery (last resort)