Tinea Pedis

What is tinea pedis?

• “Athlete’s foot”

• Superficial fungal infection of feet and toes mainly caused by dermatophytes (fungal organisms that need keratin for growth)

• Fungi infect superficial layers of skin, stratum corneum by digesting keratin which allows them to survive and multiply

  • SC: outermost layer of epdiermis, has cornified keratinocytes w intercellular spaces sealed w lipids. KC primary cells type form protective barrier against env damage

  • Keratin: fibrous, tough protein made by keratinocytes, main cells of epidermis, gives structure to hair nails helping resist physical and env stress

What factors contribute to the growth of dermatophytes?

• Hot and humid environments

• Excessive sweating

• Prolonged exposure to water

What is the pathophysiology of tinea pedis?

• Dermatophytes attach to the skin using adhesins on their cell wall.

  • Proteins in fung cell wall which resp for attachment of fung cells to biotic+abiotic surfaces

• They produce proteases that break down keratin 

• Keratinocytes respond by releasing cytokines to fight the infection.

  • Small proteins released by cells that act as signals, talk w other cells to trigger specific resps

• Mannans in the fungal cell wall can suppress the immune system, making infection more likely

  • Type of polysach made of mannose units commonly found in hemicellulose fraction of many cell walls

What are patient risk factors for developing tinea pedis?

• Ppl who walk barefoot in community locker rooms, showers, or swimming pool areas (infection usually acquired by direct contact worganism)

• Diabetic patients: More susceptible to fungal skin infections in general as hyperglycaemia in patients affects cellular immunity and circulation   

• Ppl who wear occlusive shoes and for extended periods of time 

• Ppl who participate in sports involving feet being moist or wet e.g. swimming / running

• Adult males have a higher prevalence of tinea pedis than females

• Patient w weakened immune system e.g. those on immunosuppressants 

• Adults w vascular / circulation issues

• Hyperhidrosis - excessive sweating

How does tinea pedis present?

• Long-standing, itchy, intertriginous dermatitis of the toes characterised by peeling, maceration, and fissuring