A reader asked if I could also talk about fungal infections of the skin... Like fungal nail infections, these are also very common, quite unpleasant and sometimes misdiagnosed...
Fungal skin infections, also called “tinea corporis”, include infections such as Athlete’s Foot, Jock Itch, and Ringworm (caused by fungus, not worms!). The scalp can also become infected with fungus and this is a common cause of itchy dandruff.
Fungal skin infections often grow as a red circular rash that is brighter red and slightly raised at the borders as the fungus grows into healthy skin. The rash is usually itchy but not painful, and can spread into new skin as round red “dots”. Sometimes the red border is not visible, leaving only itchiness and rough skin, making diagnosis more difficult.
Along with their related personal history (How long have you had the rash? How did it start? etc.), I often consider the characteristics of 3 basic types of infectious skin rashes when helping a client decide what non-prescription treatment to try. These are the criteria I use to base my treatment recommendations:
Bacteria – usually painful, red, and form pus and scabs as the infection advances.
Virus – less common (cold sores are an example), painful, usually see water-filled “bubbles” or vesicles on the surface of the skin in the early stages.
Fungus – itchy, not usually painful, often a circular rash, tends to spread in “dots”
All of these infections are contagious. They can be spread through direct skin contact with an infected person or animal, or via objects recently touched by an infected person or animal. Fungal infections are fairly common in dogs, cats and cows (if you have one of those!). Occasionally an infection can develop from prolonged contact with contaminated soil.
Skin fungal infections
Skin fungus often starts with a flat scaly area that is red and itchy, spreading outward forming a raised red “ring” that is roughly circular. The infection is more active as it moves into uninfected skin, creating the raised red border that is characteristic of this type of infection. The center may look clear, scaly or have scattered red bumps.
The infection affects only the outer layer of skin in most cases. Rarely it will invade lower skin layers, but usually only in people with a compromised immune system.
Risk factors
Living in a warm climate and wearing tight clothing or shoes that don’t breathe (trapping moisture). Fungi like to grow in warm moist environments.
A weakened immune system
Close contact with an infected person or animal, or sharing clothing, bedding, towels, etc.
Skin-to-skin sports (e.g. wrestling). If sports equipment becomes contaminated and is packed away while still damp (e.g. hockey gear), it can become a source of fungal skin infection.
Diagnosis
If the outer “ring” is not visible, it is easier to misdiagnose a fungal skin infection. Examining skin scrapings with a microscope can confirm the diagnosis of a skin infection, but often a “trial and error” approach is used – if the rash hasn’t improved after using an antibacterial cream or corticosteroid cream (helpful for rashes caused by irritation or eczema), then it is logical to try an antifungal cream, especially if itching is present.
Some doctors will take a “multi” approach if unsure of the infection type, prescribing a cream containing an antifungal, antibacterial and a corticosteroid to cover several causes at once.
Treatment
Treating an infection early gives a better chance of success with creams. If a large area is involved or the person has a weakened immune system, they may need to take an antifungal medication by mouth. However, as you will recall from last week’s blog, these have significant side effects.
Apply the cream to the rash area and into the uninfected skin in the surrounding area also to prevent spread. Follow any instructions on the label. Continue to use the cream for 2 weeks, or for several days after the visible rash is gone to ensure all the fungus is destroyed. If the rash has not cleared in 2 weeks, see your doctor. Be sure to tell him/her what treatment you have used.
Keep the area as dry as possible – fungus likes a moist environment. If the infection is on your foot, treat your shoes with an antifungal spray and let dry well between uses to prevent reinfection.
Change towels/wash cloths used on the infected area often to prevent reinfection.
If the infection is very itchy, you can alternate antifungal cream with a corticosteroid cream (such as hydrocortisone 0.5 to 1%) to reduce itchiness. Scratching can worsen or spread the infection. Depending on the rules in your state or province, you may be able to ask your pharmacists to make a cream with both ingredients (adding hydrocortisone powder to an antifungal cream) for convenience.
Ask your vet to check your pet for infection and treat if present.
Don’t share personal items if you have an infection to avoid infecting others.
If you have a chronically itchy scalp with dandruff, try an antifungal shampoo. If severe or long-standing, I would suggest a higher strength antifungal shampoo, such as Selsun Regular (stronger than Selsun Blue) or Nizoral shampoo. Your pharmacist can also make cetrimide 1% with hydrocortisone 0.5% in water for you. This is used by applying drops to wet hair after shampooing, rubbing into the scalp (it will foam), and leaving in. This has the advantage of longer treatment contact than a shampoo could provide, and is not visible on the hair once it dries. Again, keep in mind that some states (strangely) do not allow compounding without a prescription.
