We know it can be difficult to determine whether that annoying rash is a sign of something serious or just an everyday allergic reaction that will subside in a matter of hours. Sometimes it’s something you’ve experienced before…other times it just comes out of nowhere and can be a little frightening.

So to help you figure out whether you need to make an appointment with a dermatologist or not, here is a breakdown of the most common skin conditions you will encounter by category, and what you should or shouldn’t do if you notice one of them on your arms, legs, face or elsewhere on your body:

I have some kind of rash developing

Skin rashes, commonly defined as localized patches of discoloration on the skin, can be caused by many different factors, including allergens, anxiety or an underlying illness. In most cases, a rash is nothing more than an annoyance and will go away on its own or can be easily treated at home. In some cases, a rash will require more comprehensive treatment, requiring the services of a dermatologist.

There are certain indicators that can help you determine the potential severity of a rash. These include the color of the rash, the appearance of fluid or crusting, and its location on your body. Generally speaking, rashes range from pink to red to purple. Measles will manifest as bright red, while chicken pox is a lighter pink. The initial color itself may not signal a problem but if your rash suddenly changes color, that is a sign of a more serious problem and you’ll want to have it checked out by a dermatologist.

Likewise, while the location of the rash can help to identify its cause (poison ivy generally appears on the ankles; measles on the cheeks) if the rash spreads quickly, that is when you need a dermatologist to look at it. A rash that appears crusty or contains pus filled pockets could be the result of an underlying viral infection and should be seen by a doctor right away.

My skin is very itchy all of the sudden

An itch is one of the most common forms of skin irritation. In most cases, itching is not a sign of anything serious and will go away spontaneously. Sometimes, itching can be a symptom of a larger problem including allergic reaction, anxiety, a nerve disorder or even a kidney ailment. A localized itch, one that occurs in a specific area of your body, is easier to identify and treat.

There are a number of over the counter medications such as Caladryl, Calamine and Benadryl, that can be used to alleviate itching. When itching is accompany by other symptoms such as bumps, blisters or rash, then it may be related to a condition such as eczema or scabies. This type of itching should be evaluated by a dermatologist as it may require more specialized treatment in order to address the underlying cause.

Why is my skin so dry all the time?

The skin is naturally protected by oils designed to keep it soft and moist. When those oils are stripped away, for one reason or another, the result can be dry, itchy skin. There are many ordinary causes for dry skin including excess washing, allergic reaction and hormonal changes. In most cases, dry skin can be successfully treated using moisturizers, mild soaps and humidifiers. If these self help treatments don’t relieve your dry skin over a period of two weeks, then you’ll want to consult a dermatologist.

Persistent dry skin can be a symptom of a more serious condition including diabetes and thyroid disorder. In those cases, you’ll need to treat the underlying condition in order to address the dryness. In cases of severe dry skin, a dermatologist can prescribe topical antihistamines or corticosteroid creams. Dry skin that is left untreated can lead to cracking and oozing and even localized infection so it is important to get proper treatment as soon as possible.

What are all of these blisters and bumps?

Skin conditions can take many different forms. One of the most distressing is blistering or raised bumps. Blisters are pus filled pockets that develop on the skin and they can be caused by a number of things. The most common cause is friction. This is what causes them to form on the feet when you wear tight shoes.

But blisters and other raised bumps can also be a symptom of an allergic reaction. In most cases they occur one at a time and are not serious. These types of blisters will eventually go away on their own. Blisters that occur in large numbers or persist for more than a week may be a sign of a more serious medical condition and should be seen by a dermatologist.

I’m noticing some skin discoloration

The skin contains cells that produce normal pigment, called melanin. Various conditions can cause a disruption in the production of melanin, which in turn results in discoloration of the skin. Not all skin discoloration is necessarily serious; often allergic reactions or exposure to the sun can cause reddening of the skin. This is usually temporary and will resolve on its own.

Other discolorations are more serious and require the attention of a dermatologist. This includes yellow or orange tinge to the skin, which often indicates liver problems. Orange coloration can also result from a diet heavy in carotene rich foods and is usually more common in infants. Pale skin is a common side effect of illness, both mild and severe, and can be spread over the whole body or localized in the fingers. By far the most serious type of discoloration is cyanosis. This is a condition when the skin turns blue due to a lack of oxygen. This is considered a critical condition and should warrant immediate medical attention.

The most common types of discoloration seen by dermatologists are hyperpigmentation, or darkening of the skin, and hypopigmentation, or loss of skin color. Each of these discolorations can be a symptom of specific skin conditions including vitiligo and even skin cancer and they should be diagnosed by a qualified dermatologist.

I feel a tingling sensation in my skin

Tingling of the skin, also known as paresthesia, is a condition caused when sensations from the skin are not properly transmitted to the brain. This tingling is usually temporary and can have a number of causes. The most common is the application of pressure to a particular nerve for a prolonged period of time. This results in the “pins and needles” sensation that is most often described as your leg or arm “falling asleep”. Restoring sensation to the nerve will alleviate the tingling.

Other causes of tingling include dehydration, panic attack, seizures and TIA or transient ischemic attack, otherwise known as “mini strokes”. When tingling accompanies a skin rash, this can indicate conditions such as eczema, folliculitis or even a brown recluse spider bite, which can be extremely serious. If you experience a rash and tingling of the skin, you should consult your dermatologist to get a proper diagnosis and treatment.

When in doubt seek medical attention

The skin is the largest human organ but it is also the most delicate and requires special care and attention. If you experience one of the symptoms above and it doesn’t seem to fade over time or gets worse, definitely set up an appointment with your dermatologist as soon as possible and find out what the story is. It may be nothing…but it may also be something serious, so it’s better to be safe than sorry.