Dermatology

The athlete's foot is a type of fungal infection of the foot that develops between the toes. It is called "Athlete's foot" because it typically occurs in people whose feet become very sweaty in tight shoes, usually due to long physical activity. Associated Anatomy of Athlete’s Foot Foot Alternate Name of Athlete’s Foot Tinea pedis Additional Type of Athlete’s Foot An additional type of athlete’s foot infection is ringworm infection, caused by another fungus called Candida. However, ringworm is more prominent in children and is found between the toes or the scalp. Athlete’s Foot Causes The cause of an athlete's foot infection is a fungus called Trichophyton. These fungi are normally present on the human skin but do not cause infection. They can cause infection when: There are breakages in the skin surface which allow these fungi to thrive and reproduce There is moisture and warmth brought about by constant activity in tight shoes, which allows the fungi to grow Damp socks can cause Athlete's foot Contact with someone who is infected with this fungus can also cause Athlete's foot. Athlete’s Foot Symptoms The signs and symptoms of an athlete's foot infection include: Itchy, scaly skin between the toes Stinging or burning sensations in the skin between the toes Cracking of skin and development of oozing and crusting Itchy, pus-filled blisters Delay in the healing of the cracked skin. Stages of Athlete’s Foot Athletes’ feet are easily treatable and do not progress into further stages if treated appropriately. Athlete’s Foot Diagnosis An athlete’s foot is easily diagnosed by visual examination. The confirmatory test for this fungal infection is swabbing an area of the skin and placing it in a solution of potassium hydroxide, i.e., KOH. This leaves the fungal cells intact in the sample, which can be visually examined under a microscope and identified. Differential Diagnosis for Athlete’s Foot A microscope's visual examination can differentially diagnose an athlete’s foot. The sample from the affected tissue is collected and placed in a potassium hydroxide solution, or KOH. This kills the normal cells and leaves the infected cells intact, examined using the microscope used to diagnose. Athlete’s Foot Treatment In most cases, an athlete's foot infection can be easily treated using OTC medications. These may include topical medications like liquids, sprays, creams or powders. Common medications include ketoconazole, miconazole, and sulconazole The doctor recommends oral medications if the topical medications don't work. Some examples include griseofulvin, Itraconazole, terbinafine, etc. Doctors also suggest home remedies such as salt baths and tea tree oil for alleviating symptoms. The best way to ensure quick recovery is to keep the area as dry as possible to prevent further fungus growth. Risk Factor of Athlete’s Foot As the name suggests, athletes are more susceptible to contracting this fungal infection due to constant friction in the foot due to continuous physical activity. Using plastic shoes may put you at a higher risk of contracting this fungal infection than leather or canvas shoes. Damp shoes and damp socks that have not appropriately dried may support the growth of the fungus. People with immune disorders are also more likely to contract fungal infections. Possible Complication of Athlete’s Foot If left untreated, a site where an athlete's foot infection has developed may also become a site for bacterial infection which may spread to the bloodstream of the infected person. This infection may culminate in the lymph system and spread further. However, this is a rare complication. Athlete’s Foot Prevention Primary Prevention of Athlete’s Foot Preventing friction in the feet area can help prevent this infection Avoiding the use of ill-fitting shoes is recommended to prevent athlete's foot Regular washing and cleaning of the feet and occasional soaks in saltwater are effective in preventing fungal infections Dabbing the area with talcum powder to soak up excess sweat and moisture is also helpful. Avoid sharing footwear. Secondary Prevention of Athlete’s Foot Secondary prevention and primary prevention of athlete’s foot are the same. Having an athlete’s foot infection once does not predispose you to have it again and again if hygiene is maintained correctly. Applying antifungal medications regularly can be helpful but may contribute to the resistance of the fungi to the medicine in the long run. Epidemiology of Athlete’s Foot Athlete's foot infections are more likely to occur in men than women [24.2% in men compared to 6.1% in women] Older people are more likely to contract it from shared shoes or an infected person. Expected Prognosis of Athlete’s Foot Athletes’ feet are easily treatable and resolve quickly with regular hygiene and timely medications. The affected skin heals to give rise to the normal skin soon after the infection dissolves. Natural Progression of Athlete’s Foot If not treated, the athlete’s foot infection may spread to other areas of your foot, such as toes which may become infected, resulting in their discolouration and crumbling. In rare cases, it may also spread to your hands and groin. Pathophysiology of Athlete’s Foot An athlete’s foot is a superficial infection of the skin of the feet. The fungus Trichophyton is a dermatophyte which releases enzymes that dissolve the skin cells and grow in the moist conditions of the skin layers. The fungus then reproduces in these conditions and thrives in moisture and warmth.

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Post-herpetic neuralgia, in simple terms, means nerve pain post herpes zoster or shingles. It is a painful condition affecting skin and nerve fibres. It is the most common complication of shingles. If you experience pain at the site of shingles even after the rash has resolved, it is called post-herpetic neuralgia (PHN). Post-Herpetic Neuralgia Causes If you’ve had chickenpox, the varicella-zoster virus (the virus that causes chickenpox) remains in your body for a lifetime, and sometimes it gets reactivated in older age or if you develop a weak immune system, resulting in shingles, which appears as blisters and rash on one side of the body, mostly at the trunk area. In about 20% of patients, the pain remains for weeks, months, or even years even after the rash has resolved. This is called post-herpetic neuralgia. It is caused due to damaged nerves at the site of shingles rash, affecting their structure and functioning. These nerves send improper signals to the brain, causing exaggerated pain responses. Post-Herpetic Neuralgia Symptoms Signs and symptoms of post-herpetic neuralgia are generally limited only to the area where shingles had appeared and include: Severe, burning, jabbing-kind of pain at the site, lasting for more than three months. Hypersensitivity to touch. Sometimes, even the touch of clothing to that area is intolerable. Itching and numbness around the area of the prior rash. Slight fever and malaise. Post-Herpetic Neuralgia Diagnosis No diagnostic tests are required to confirm the diagnosis of post-herpetic neuralgia. It is diagnosed based on the symptoms, physical examination, and history of shingles. If you recently had an outbreak of shingles rash and are experiencing pain in the same area even after the resolution of the rash, you most likely have post-herpetic neuralgia. Post-Herpetic Neuralgia Treatment A single treatment modality is usually not sufficient to relieve post-herpetic neuralgia, so a combination of medications can be prescribed, including: Creams: Topical creams containing pain-relieving medications like lidocaine or capsaicin provide temporary pain relief. Oral pain medications: Painkillers such as acetaminophen or NSAIDs like ibuprofen, etc. are prescribed to relieve acute pain and inflammation. For severe pain, these may be prescribed Anti-seizure medications: Anticonvulsant drugs such as gabapentin control the abnormal electrical activity caused by damaged nerves, relieving pain from herpetic neuralgia. Antidepressants: They are given in small doses to affect brain chemicals that alter how the body interprets pain. This is done to control post-herpetic neuralgia. Opioid painkillers: In rare cases of severe pain, opioid painkillers like tramadol, oxycodone, or morphine are given, but CDC guidelines restrict opioids for non-cancer-related pain because they are addictive. Risk Factors of Post-Herpetic Neuralgia Certain people are at higher risk of developing post-herpetic neuralgia. These include: Age above 50: If you develop shingles after the age of 50, there are more chances of developing post-herpetic neuralgia. Severe shingles: If you had a severe shingles outbreak, you are at a higher risk of developing post-herpetic neuralgia. Weak immune system: Weakened immune system reactivates dormant varicella-zoster virus. The immune system gets weak by age, by certain chronic conditions like AIDS, by receiving chemotherapy for cancer treatment, immunosuppressive medications after organ transplant, etc. Delay in shingles treatment: Consult a doctor and start antiviral therapy within 72 hours of the appearance of the shingles rash. If the therapy is delayed, the risk of post-herpetic neuralgia increases. Symptoms before shingles rash: If you had symptoms like pain, itching, numbness, or tingling at the site before shingles rash, you most probably have post-herpetic neuralgia symptoms post-resolution of the rash. Complications of Post-Herpetic Neuralgia The pain and discomfort caused by post-herpetic neuralgia can be disabling and interfere with daily life. The complications of PHN may include: Difficulty sleeping. Fatigue. Decreased appetite. Poor concentration. Depression. Post-Herpetic Neuralgia Prevention Vaccination: Vaccination is an effective measure to prevent shingles and PHN. FDA has approved a recombinant herpes-zoster vaccine, Shingrix, for people ages 50 and above to prevent shingles. It is given in 2 doses, 2 to 6 months apart, and is 90% effective in preventing shingles and PHN. This vaccine protects for at least 4 years. If you’ve never had chickenpox, get yourself vaccinated with the chickenpox vaccine. This will prevent the varicella-zoster virus from getting into your body, and thus you will not have a chance of developing shingles or PHN. The vaccine, Shingrix, is recommended even if you have had shingles, to prevent post-herpetic neuralgia. Initiation of Shingles treatment within 72 hours: Getting early treatment for shingles also reduces the risk of getting PHN. Antiviral therapy needs to be initiated within 2 to 3 days of developing the rash. Thus, if you think you have shingles, visit your doctor promptly. Epidemiology of Post-Herpetic Neuralgia Post-herpetic neuralgia is most commonly seen in patients of age 50 and above. Women seem to be more prone to PHN than men. Individuals with chronic conditions like diabetes, or those with conditions that weaken the immune system, such as HIV and cancer, are more likely to develop PHN. Prognosis of Post-Herpetic Neuralgia There is no cure for post-herpetic neuralgia, but pain and other symptoms can be effectively managed with medications. In most cases, the pain resolves within 1 to 3 months, though it is not uncommon to last for a year or more. Natural Progression of Post-Herpetic Neuralgia For most people, post-herpetic neuralgia resolves over time in about 3 months, though it might last for several years in some patients. Treatment should be taken for the management of pain and other symptoms. If left untreated, post-herpetic neuralgia can become a severe and debilitating disease. Pathophysiology of Post-Herpetic Neuralgia Post-herpetic neuralgia is caused due to damage to nerve fibres at the site of shingles rash. These nerve fibres can no longer transmit messages from the skin to the brain as they usually do. The messages now become exaggerated and confused, resulting in a chronic, sharp pain that can last for months or even years.

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