Patchy skin: harmless or harmful?

Lots of things can cause skin discolouration

“I had to relearn how to love myself by forgetting the opinions of everyone else and focusing on my opinion of myself.”  Winnie Harlow (woman with vitiligo).

Discoloured skin patches are quite common and are caused by a range of different factors including birthmarks, pigmentation disorders, rashes, and infections. Some causes are harmless, but others may need medical attention. A recent article brings these to mind and we outline the main causes.

Skin itself is the pigment that gives human skin, hair and eyes their colour. Darker-skinned people have more melanin in their skin than lighter-skinned people.

Discoloured skin patches are noticeable because they differ from a person's normal skin tone. They may be lighter, darker, or a different colour, such as red, grey or even blue. It's important that people with this symptom understand the cause of their discoloured skin patches in case treatment is necessary.


Birthmarks are coloured marks that are visible on the skin. They're often present at birth or develop soon afterwards. There are several different types of birthmark and some of them are very common.The two main types of birthmark are:

  • Vascular birthmarks (often red, purple or pink) caused by abnormal blood vessels in or under the skin
  • Pigmented birthmarks (usually brown) caused by clusters of pigment cells.

Some types of birthmark fade over time, while others may be permanent.

Skin pigmentation disorders

If a person has lighter or darker skin patches, this may signify a skin pigmentation disorder. Type of skin pigmentation disorder include:

  • Melasma: also called ‘chloasma’, this is a common skin condition of adults in which light to dark brown or greyish pigmentation develops, mainly on the face. Although it can affect both genders and any race, it is more common in women and people with darker skin-types who live in sunny climates. Melasma usually becomes more noticeable in the summer and improves during the winter months. It is not an infection, it is not contagious and it is not due to an allergy. Also, it is not cancerous and will not change into skin cancer. Triggers of melasma can include sun exposure and hormonal changes
  • Vitiligo: a condition in which areas of skin lose their normal pigment and so become white. It is common, and affects about 1% of the world’s population. The pigment that gives your skin its normal colour is melanin, which is made by cells known as melanocytes. The cause of vitiligo is not yet fully known but many think that it is a disease in which the body makes antibodies to its own melanocytes, and in doing so destroys them. After that, the skin cannot make melanin properly, and vitiligo is the result. In support of this idea is the way that people with vitiligo are more likely than others to have diseases, caused in much the same way, of other organs such as the thyroid. It affects men and women of all races equally, but is most easy to see in people with dark skins. It is not catching
  • Post-inflammatory hyperpigmentation/hypopigmentation:  a temporary increase or decrease in skin pigment following skin trauma, such as a blister or burn
  • Albinism: people with albinism do not produce enough melanin. This leads to little or no pigment in the skin, hair, or eyes. Albinism is a genetic disorder, meaning that a person inherits a faulty gene from one or both of their parents.

Skin rashes

Some types of skin rash can also cause patches of discoloured skin. These include:

  • Rosacea: a chronic skin condition that can cause raised patches of red skin and pus-filled lesions. It typically affects the forehead, cheeks, and nose
  • Psoriasis: a skin condition that causes silvery-red, crusty, flaky patches of skin, which can appear anywhere on the body. Doctors believe that psoriasis may result from a problem with the immune system
  • Contact dermatitis: a rash that happens when the skin reacts to an irritant or allergen
  • Eczema: also known as atopic dermatitis, this condition can cause patches of red skin that is also itchy, dry, and cracked. These patches may sometimes ooze and then form a crust. The cause of eczema is unclear, but it can run in families and is more common in people who have asthma, hay fever, and other allergies.

Skin infections

  • Tinea versicolour: a fungal skin infection that can cause patches of skin to become lighter or darker. These patches usually develop slowly and can sometimes merge to form larger patches. It tends to affect the trunk, neck, and upper arms
  • Ringworm: also known as tinea, this is a fungal skin infection that causes red or silver ring-shaped patches of skin. These patches may be scaly, dry, or itchy. Ringworm can appear on most parts of the body, including the scalp, groin, feet, hands, and nails
  • Candidiasis of the skin: a fungal skin infection that causes red, itchy skin patches. It often occurs in areas where the skin folds, such as the armpits and groin.

Skin cancers

In rare cases, skin cancer can cause patches of discolouration. Types of skin cancer include:

  • Actinic keratosis: dry, scaly, pre-cancerous skin patches. Without treatment, they may progress to squamous cell carcinoma
  • Basal cell carcinoma: flesh-coloured, pearl-like, pink skin patches or bumps. Basal cell carcinomas are the most common form of skin cancer
  • Squamous cell carcinoma: red bumps, sores, or scaly patches, which may heal and then re-open. Squamous cell carcinomas are the second most common type of skin cancer
  • Melanoma: this cancer may develop in existing moles or appear as new dark spots. Melanomas are the most severe form of skin cancer, and early diagnosis and prompt treatment are crucial.

Medical conditions

  • Cyanosis: insufficient oxygen in the blood can cause the skin and lips to appear blue or purple. Cyanosis that occurs suddenly could be a sign of a problem with the heart, lungs, or airways. This is a medical emergency, and a person should seek immediate medical attention
  • Lupus: a complex autoimmune condition that may cause a butterfly-shaped rash on the cheeks
  • Undiagnosed or untreated diabetes can also cause changes in the skin, such as yellow, reddish, or brown patches of skin, dark, velvety patches of skin, thick, hard patches of skin, blisters, shin spots,

Other causes

If discoloured skin patches appear suddenly and then disappear, there may be a simple explanation. Causes of temporary patches or blotches of red skin include:

  • Blushing
  • Exercising
  • Sunburn.

Causes of temporary patches of pale skin include:

  • Dehydration
  • Nausea
  • Low blood sugar
  • Cold weather conditions.

Speak to your GP, as above or your OH provider if you have any concerns.

There are lots of resources out there to help including and