Getting to grips with RSI
Q. Every patient knows dark rings under the eyes are due to being tired or 'run down'. Some people do seem to habitually have dark areas on the skin just below the eyes, more obvious on those with paler skin. Is there any medical significance and what is it that gives the dark appearance?
A. Dark circles under the eyes are caused by two sometimes co-existing problems.
First, either with age or genetic predisposition, the eyeball descends within the orbit. Peri-orbital fat is squeezed into the infra-orbital space creating a pseudo-herniation, exacerbated by increased skin and muscle laxity, brought on by age, smoking or sun exposure.
Second, infra-orbital pigmentation may be present, either as post-inflammatory hyperpigmentation, or by a predisposition for increased melanin deposition. The shadow of the orbital ridges can exaggerate dark circles.
Pseudo-herniation can be treated surgically. Blepheroplasty involves excising fat and skin from the lower eyelid.
Scarring is usually imperceptible but the eyes can adopt a sunken appearance. Fat can also be pushed back into the orbital space and the defect over-sown to prevent recurrence, or the orbit can be resuspended.
In post-inflammatory hyperpigmentation, both melanin and heamosiderin pigments are present.
These can be very difficult to dissipate. With time, the pigment tends to fade. These patients are usually atopic and treating the underlying condition helps.
Where the pigment is due to dermal melanin deposition, it can be successfully removed by deep chemical phenol peels; or a series of Q-switched Ruby or Alexandrite laser treatments; or CO2 laser resurfacing.
Laser resurfacing can cause hypopigmentation in darker skin types or if too many laser passes have been carried out. Partial rather than complete pigment loss is to be expected.
Topical depigmentory products such as hydroquinone or attempts to improve skin laxity with topical retinoids or anti-oxidants have proved disappointing. Camouflage may ultimately be the easiest solution.
Dr Tony Downs, consultant dermatologist, Royal Devon and Exeter NHS Foundation Trust