What it is
The most common link is insulin resistance, which is associated with weight gain, prediabetes and type 2 diabetes. It can also be linked to hormonal conditions such as polycystic ovary syndrome, some medicines and, rarely, to cancers inside the body.
Treating the underlying cause often makes the patches fade over time.
Common signs
- Darker, thicker, velvety skin in the armpits, neck, groin or under the breasts
- Sometimes itching or skin tags in the same area
- Patches that appear or spread quickly in an adult
How it is usually diagnosed
- A doctor can usually recognise it by looking at the skin
- Blood tests for blood sugar and HbA1c, and sometimes hormone tests
- Rarely a skin biopsy, or further tests if the patches appeared suddenly
Records worth keeping
Keeping these together makes each appointment easier, especially when you see a new doctor:
- Photos of the patches with dates, to see change over time
- Blood sugar, HbA1c and hormone test results
- Dermatology letters
Questions to ask your doctor
- What do you think is causing it?
- Which blood tests should I have?
- Will the patches fade if the cause is treated?
When to get help right away
Call 112 or go to the nearest emergency department if you have:
- Patches that spread very fast together with unexplained weight loss, and you cannot get a prompt appointment
This page is general information. It is not a diagnosis and does not replace a doctor who knows your history. Medfold keeps your records organised; it does not interpret them.