What should you know about caf au lait spots suddenly appearing in adulthood?

Classic caf au lait spots are flat, smooth patches with fairly even light-brown colour and are often noticed earlier in life. A mark first seen in adulthood may still be benign, but it may instead be a sun-related change, post-inflammatory pigmentation, a fungal colour change or another type of mole. Its timing alone cannot identify the cause.

A clinician assesses the outline, shade, surface and nearby skin, then asks about sun exposure, rashes, injury, new medicines and family history. This is especially helpful when the patch was not visible in older photographs.

Take a clear dated photograph beside a ruler or familiar object, without using filters, and note the date you first noticed the mark. Do not scratch it or apply strong acids and bleaching agents before assessment. Daily sun protection can reduce darkening and makes future comparisons easier.

Arrange a routine appointment if the patch is stable and you feel well. A clinician may recommend observation, a closer examination or a procedure only after identifying the mark. Treatments intended for acne, such as LED Light Therapy, should not be assumed to treat unexplained pigmentation.

Request prompt assessment if the new patch expands quickly, has an irregular edge, contains noticeably different colours, becomes thick, ulcerated, painful, itchy, crusted or prone to bleeding. Seek earlier advice when multiple new pigmented marks appear or when you also have unexplained general symptoms. Urgency is based on these warning features, not on the fact that most pigment marks are harmless.

Ask what diagnoses are being considered and which feature supports each one. You can also ask whether dermoscopy is useful, how the mark should be photographed, how soon it should be reviewed and whether a biopsy is necessary. If you are pregnant, breastfeeding or taking medicines, mention this before discussing treatment.