What should you know about hypopigmentation after sun exposure?

Sun exposure can darken surrounding skin, making an existing pale area easier to see. In other cases, inflammation, a superficial yeast-related condition such as tinea versicolor, or a pigment disorder may account for the difference. Atopic dermatitis can leave lighter areas after irritation has improved. Patches may be smooth or slightly scaly and can occur on the trunk, arms, face or other exposed areas. Colour and texture, symptoms, previous rashes and how the patches change are useful clues, but appearance alone cannot identify the cause.

Use broad-spectrum sun protection, clothing and shade to reduce contrast and prevent further irritation. Do not scrub, peel or apply strong lightening products. Take clear photographs in similar lighting and note whether the patches itch, scale or follow a rash. A dermatologist can examine the surface and may use a special light or skin sample when the diagnosis is uncertain. Treatment depends on the cause and may include care for inflammation, an antifungal medicine or selected pigment-directed therapy.

Book a review if patches spread, become sharply defined, develop scale, itch or do not blend as the tan fades. Seek prompt care for painful blistering, marked swelling, fever, pus or a severe sunburn reaction. A rapidly changing patch, bleeding spot or non-healing area needs examination rather than cosmetic camouflage.

Ask whether the surface is scaly, whether a fungal or inflammatory condition fits the pattern, and whether any medicines or skin products may be contributing. Ask when colour may be reassessed, which sunscreen routine is practical for you, and whether topical calcineurin inhibitors or excimer laser therapy have a role.