The photo shows a small, dark blue-purple, linear area on the temple/scalp near the hairline. It could be a superficial vein, minor bruise, or localized pigmentation. A photograph cannot reliably distinguish these from a pigmented skin lesion.

Arrange an in-person examination, preferably with a dermatologist or primary-care clinician, especially if this is new, enlarging, changing in colour or shape, raised, painful, itchy, bleeding, crusting, or does not fade within 2 to 3 weeks. Changes in a spot's size, shape, or colour are warning features that should be assessed, as described by the American Cancer Society's melanoma signs guide.

Seek urgent medical care today if it appeared after a head injury, is rapidly spreading, or is accompanied by severe headache, confusion, weakness, visual changes, fever, or unusual bleeding/bruising.

For comparison, take a well-lit close-up photo with a ruler beside it today and note whether it changes.

In an 80-year-old who is bedridden, this may be a small scratch-related bruise/purpura. Older skin is thinner and small blood vessels can break with minor rubbing, scratching, or pressure. Dry skin is also a very common cause of itching in older adults. The mark in the photo looks more like a localized blue-purple bruise than an obvious infected rash, but it cannot be confirmed from an image.

Arrange a clinician review within a few days, sooner if this is a new unexplained mark or if the itch is recurrent. They should review her medicines, particularly aspirin, clopidogrel, warfarin, apixaban/rivaroxaban, heparin, steroids, or frequent ibuprofen, because these can increase bruising. Persistent generalized itch can also sometimes relate to medication effects or medical conditions and deserves assessment.

Seek urgent care today if:

If it is simply a minor bruise, it should gradually change colour and fade over roughly 1 to 3 weeks. If it persists, darkens, becomes raised, or keeps returning in the same spot, it needs direct examination.