How do you know if you have a fungal skin infection or eczema?

A dermatologist... ...Will take a sample of the scale from the rash, put it under the microscope, and look for fungal elements (we call them "hyphae"). If they are present, it's a fungal infection; if not, eczema or something closely related in most cases.
Dermatology. A dermatologist can evaluate and treat according to diagnosis. Cultures can be done of the skin to help with diagnosis. Topical and oral treatment can help. I recommend not letting it go to long without treatment.

Related Questions

How do you know if you have a fungal skin infection or if it's just eczema?

It can be tricky. There is overlap between the appearance and symptoms of eczema & fungal infections. Both can be red, scaly and itchy. Mild eczema responds well to moisturizers & Hydrocortisone cream. This treatment can actually worsen some fungal infections. Fungal infections respond well to antifungal creams. If your rash is not improving, see your dermatologist. A simple non-invasive skin test can sort it out. Read more...
Culture . It is often difficult to determine if you have a fungal skin infection if you have a known history of eczema. The best course of action is a culture or skin scraping. Read more...

What do you needs to avoid when you have a fungal skin infection like jock itch?

Heat, moisture. Skin fungi love warm, damp areas such as the groin and feet, which is why jock itch and athletes' foot are so common. Your job is to keep the involved area as cool and dry as possible. In the case of jock itch, wear loose underwear and apply a good powder like zeasorb twice a day. And of course, apply a good antifungal cream or lotion twice a day until the rash clears. Read more...

Is it better to be using a bar of soap or liquid on my body if I have a fungal skin infection?

Doesn't matter... ...As long as you use one or the other regularly. Fungus infections love warm, damp skin -- so the cooler and dryer you can keep the involved area, the faster the infection will resolve. Read more...

I seem to have a fungal skin infection I can't completely get rid of. I've seen a doctor who recommended I use a topical antifungal but I still get it?

Ask for fungal test. Fungal infections of the skin can be definitively diagnosed by viewing a skin scraping under the microscope, doing a fungal culture, or a skin biopsy. Once the diagnosis is definitively confirmed, oral antifungal pills and topical creams such as naftin (naftifine) are effective at clearing it up. Read more...

Is there another condition that could easily be confused with a fungal skin infection?

Xerotic eczema. Xerotic eczema, a condition presented commonly in elderly and in winter, can look like ringworm. Read more...
Fungal confusion. The most common conditions that would be confused with fungus on the feet and hands is psoriasis and eczema. If on the body then it can be confused with nummular dermatitis and granuloma annulare. Read more...