Patches are spots of skin that are lighter or darker than your regular skin color. Patches may also have a red, purple, or blue tint. Not to be confused with macule (discoloration smaller than 10 millimeters), patches are much larger. Birthmarks, vitiligo and hemophilia are all examples of patches.
What Causes Patches to Form?
Patches on the skin are usually the same texture as the surrounding skin and are typically flat. However, patches are sometimes rougher than the surrounding skin, depending on their cause.
Common conditions that cause patches include:
- eczema (a chronic skin condition that causes scaly, itchy patches, sometimes caused by allergies)
- vitiligo (a skin condition that causes white patches)
- psoriasis (an autoimmune disease where the immune system attacks skin cells)
- liver spots (dark patches associated with aging and sun exposure)
- skin moles
Some conditions of the skin can cause dry patches to form. This may result in raised, inflamed areas of skin with a rough texture.
Rashes and hives, often caused by allergies, can also cause patches to appear on the skin.
When Patches Are the Sign of Something Serious
If you experience unexplained areas of bruising or if the patches itch or leak fluid, contact your doctor. If you develop patches after coming into contact with a known allergen, seek medical attention immediately, particularly if the allergen is something you know you are severely allergic to. A severe allergic reaction often starts as a patch or two, but can quickly develop into a medical emergency.
Symptoms of a severe allergic reaction include:
- difficulty breathing
- facial swelling
- swelling around the eyes
- swelling in the throat or mouth
- rapid breathing
- weak pulse
Seek medical attention immediately if you experience any of the symptoms. Untreated severe allergic reactions can lead to anaphylactic shock. This condition can be deadly.
How Are Patches Diagnosed?
If the skin patches are not the beginning of a severe allergic reaction, you can make an appointment with your doctor in order to determine what is causing them.
Your doctor may be able to diagnose what caused your skin patches upon physical examination. However, this is not always possible. In some cases, you will be referred to a skin specialist called a dermatologist. A dermatologist will examine the skin, note any symptoms you have been experiencing, take down your medical history, and may take a sample of the patch to determine its cause.
Some allergic reactions are not emergencies. If you develop raised, itchy patches after eating a specific food or after coming into contact with a known allergen but your symptoms are not severe, you may be referred to an allergist. An allergist will perform an allergen test to determine if the patches are caused by an allergic reaction and what items might be causing it.
Either your doctor or dermatologist can tale a biopsy of your patches to help make a diagnosis if they cannot determine a cause just by examination. A biopsy involves taking a sample of the tissue and sending it to a lab to be tested.
In some cases, the cause of your patches cannot be determined by a biopsy or a skin sample alone. In this case, a blood test may be needed to determine the cause. A blood sample can show evidence of infection, autoimmune disorders, or blood disorders. This is usually done by taking a routine blood sample from a vein in your arm.
How Are Patches Treated?
Once the cause is determined, treatment options will be discussed.
If the patches are raised, inflamed, and itchy as in a mild allergic reaction, your doctor may suggest using over-the-counter anti-itch medication such as cortisone cream. This medication can work to relieve the itching and reduce inflammation. You will also be warned to stay away from the allergen that caused your reaction in order to prevent future problems.
Your doctor may give you a medication to carry with you to prevent life-threatening symptoms from occurring when coming into contact with the allergen in the future. This is usually given the form of an injection of epinephrine called Epi Pen..
If the patches are due to extreme dry skin, using over-the-counter products formulated for eczema or psoriasis may help. In some cases, these medications are not strong enough, so your doctor will prescribe an oral medication to treat it or a prescription strength cream like Elidel or Dovonex.
If the patches are due to a fungal infection such as ringworm, you may be given antifungal cream to treat the infection. Often times, an over-the-counter antifungal cream works well to treat ringworm and related causes.
Patches caused by vitiligo may be treatable in the early stages of the condition. Treatment options include:
- corticosteroid cream
- corticosteroid ointment
- immunosuppressant cream
- skin grafts
These patches can be covered using body makeup. Use sunscreen when going out into the sun to avoid sunburn on the vitiligo patches.
Patches due to blood disorders or other medical conditions will be treated according to the condition. This may include a mixture of both topical and oral medications.
Some patches have unknown causes. Treatment options for these patches will be discussed by your doctor.