Fungal Nails
(Onychomycosis, Tinea Unguium)

"Tho the world may be a jungle,
Not all funny nails are fungal."
Anonymous

People find funny-looking nails embarrassing, at least in part because many people assume that they are caused by fungus (fungal nails). This makes them sound contagious or as if they are caused by poor hygiene. In fact, up to 10% of all adults in Western countries have fungal nails. This percentage increases to 20% of adults who are age 60 or older.

In reality, "fungal nails" are often not caused by fungus at all! There are many other reasons why your nails may look different.

Here are some other conditions you may have instead of fungal nails:

1. Lines and ridges: These are common and may be considered normal. They may worsen during pregnancy. A large groove down the center of the nail can be caused by nail biting.
2. Senile nails: As you age, the nails become brittle, develop ridges and separation of the nail layers at the end of the nail. Try to avoid cleaning solutions, and don't soak the nails in water to avoid worsening of the problem.
3. Whitish or yellowish nails due to onycholysis. This means separation of the nail from the nail bed. The color you see is air beneath the nail. The treatment is to trim the nail short, don't clean under it, polish if you want to hide the color, and wait two to three months.
4. Red or black nails due to a hematoma, or blood under the nail, usually occur from trauma (like whacking yourself on the thumb with a hammer). The discolored area will grow out with the nail and be trimmed off as you trim your nails. If you have a black spot under your nail that was not caused by trauma, you may want to see a dermatologist to make sure it is not melanoma.
5. Green nails can be caused by Pseudomonas bacteria, which grow under a nail that has partially separated from the nail bed, thereby producing a green pigment. The treatment is to trim the nail short every four weeks, don't clean it, polish if you want to hide the color, and wait two to three months. It is also advised to avoid soaking the nail in any sort of water (even if inside gloves) and to thoroughly dry the nail after bathing. If the problem continues, there are prescription treatments that your doctor may try.
6. Pitted nails may be associated with psoriasis or other skin problems that affect the nail matrix, the area under the skin just behind the nail. This is the area from which the nail grows. Nails affected by psoriasis can also be tan in color.
7. Swelling and redness of the skin around the nail is called paronychia. This is an infection of the skin at the bottom of the nail (cuticle). If the infection is acute (has a rapid onset), it is usually caused by bacteria. It may respond to warm soaks but will often need to be drained by a doctor. A chronic paronychia occurs when a cuticle becomes inflamed or irritated over time. Sometimes, yeast will take advantage of the damaged skin and infect the area as well. Therapy begins with keeping the skin dry and out of water. Sometimes a steroid cream such as hydrocortisone can be used with success. If the problem continues, a physician may prescribe antifungal medications.
8. Chronic nail trauma, such as repeatedly starting and stopping, kicking, and other athletic endeavors, can cause damage to the nails that can look a lot like fungal nails. This sort of repetitive trauma can also occur with certain types of employment or wearing tight-fitting shoes.

Source: MedicineNet.com
http://www.medicinenet.com/fungal_nails/article.htm