Q I have been colouring my hair for the past eight years. My skin is sensitive and when hairdressers apply the colouring, some parts of my scalp hurt for a few seconds. Recently, I had a mild throbbing pain on one part of my scalp which lasted for a few seconds. I was quite alarmed. Is this due to a skin disease or cancer?

A The immediate irritation of your scalp due to the hair colour can either be due to the effects of the chemical on damaged skin, such as scalp eczema or hair follicle infection, or your very sensitive skin.

It is quite uncommon for a skin disease or cancer on the scalp to cause transient throbbing pain, but I would encourage you to be examined by a doctor or dermatologist to exclude any local skin condition which may account for such an unusual sensation.

If the affected area looks and feels normal, the doctor may consider the possibilities of pain arising from a problem affecting a nerve, a blood vessel, the underlying bone or, very rarely, the brain itself.

Dr Derrick Aw is a consultant dermatologist at the department of medicine, National University Hospital

This article was first published in Mind Your Body, The Straits Times on Apr 16, 2008.