A dermatologist is a medical doctor who specializes in the skin, nails and hair. Dermatologists are qualified to diagnose and treat many common scalp conditions and skin diseases.

If you notice any changes in the color or texture of your scalp, it's time to see a dermatologist. This could be:

• A rash on your scalp that is red and irritated.
• Flaking or scaling scalp skin that may resemble dandruff--but isn't as easily brushed away with a comb or fingers.
• Blotchy discoloration of the skin on top of the head (a condition called vitiligo). This can happen for no known reason and often affects only one side of the face at first; it may spread over time until both sides are affected by patches of white or grayish-white skin pigment loss (known as depigmentation). The cause is unknown but may be related to an autoimmune disorder in which antibodies attack melanocytes (cells that produce melanin).

If you have a rash that lasts longer than two weeks or has returned after going away, it's time to see your dermatologist.

Rashes on the scalp can be caused by a number of things, including dandruff, psoriasis and eczema. It's best to visit your dermatologist for an evaluation.

If you have a lesion on your scalp that does not heal, then it is important to see a dermatologist. These lesions can be signs of many conditions and it's best to get them checked out by a professional.

If you develop bumps under your skin on your scalp that do not go away, it could be caused by folliculitis or seborrheic dermatitis. These are both skin infections that are caused by bacteria and can cause redness in the area where they occur. If you notice this type of irritation, see a dermatologist right away to get treatment for it.

If you have a history of psoriasis or eczema on other parts of your body and experience new symptoms on your scalp such as redness, flaking and itching (especially at night), this could be an indication of scalp psoriasis or eczema respectively.

If you have a patch of hair loss that is not growing back after two months, then it's time to see a dermatologist. Scalp conditions can be treated by a dermatologist and can often be cured with medication or other treatments.

If you notice any changes in your scalp, it's important to see a doctor. Don't wait for the condition to get worse before consulting with a dermatologist. If left untreated, some conditions can result in permanent hair loss or scarring of the skin.