If you wake up one morning finding your scalp feeling itchy, there are many possible reasons. If you have been around children, the most likely is head lice; there is more information on that page.
Other possibilities are:
If your itching is extreme, you may want to try using either tea-tree oil or aloe vera lotion, both of which can soothe itchiness for a variety of reasons. Do not use them on babies, nor on any open sores; if you have scratched so much that your scalp has been bleeding, you may want to consult a doctor, or use a tea-tree oil cream intended for open wounds.
Avoiding harsh chemicals on your scalp
Reactions to chemicals depend upon your skin sensitivity; if your head itches after a perm or colouring treatment, you may have become sensitive to the chemicals used. The obvious cure is to avoid such treatments in future. Increasing numbers of people prefer not even to use commercial shampoos or conditioners; common ingredients such as sodium laurel sulphate can cause allergic reactions.
It is possible to depend on the hair's natural oils to keep it shiny, washing with water alone and - perhaps once a week or even less frequently - with a bicarbonate of soda (baking soda) paste. Apple cider vinegar or lemon juice can be used as natural conditioner when needed, but experience shows that when the hair is free of artificial chemicals, it becomes more manageable and less prone to itching.
Getting the right balance of washing can be difficult, depending on your hair type, the hardness of your water supply, and the ambient humidity.
Food allergies and itchy scalp
Food allergies or sensitivities may also cause itching in your scalp. If you keep a food diary, you may notice a pattern. Shellfish, nuts and wheat are known to cause an itchy scalp for some individuals, but different people react differently; try cutting out anything unusual that you ate within the previous 24 hours, or go wheat-free for a few days, and see if that helps.
If the itching in your scalp is related to a red rash, which may extend down your neck, you may be suffering from some kind of eczema. This is sometimes caused by food intolerances - dairy products and wheat being two of the commonest - so, again, an exclusion diet may help you to pinpoint the cause.
Dandruff causing an itchy scalp
If, when you comb your hair, flakes of white fall out, you may be suffering from dandruff. This is often due to nutritional deficiencies, particularly of B vitamins, and essential fatty acids. It may also result from eating too many refined carbohydrates, including sugar.
While there are shampoos intended to reduce dandruff, they contain harsh chemicals and simply reduce the symptoms; it is better to improve your diet. Try eating more fruit and vegetables, as well as seeds and nuts which can provide the necessary fatty acids. Cut down on sugar, and all white refined carbohydrate problems for a few weeks, and you may find that your dandruff goes away.
Note that many babies have a white crust in their hair, known as cradle cap. This should be gently massaged and washed only with water, and will most likely gradually disperse as they mature.
Insect bites in the scalp
If you live in a country where mosquitoes are common at certain seasons, or where there are small biting spiders, it is worth asking someone to check itchy places on your hair to see if there are small lumps, indicating bites. These can be treated with tea-tree oil or aloe vera, and should quickly heal. Eating large quantities of garlic may deter these insects, but if they remain a problem you may wish to use a net, or even a chemical insecticide.
Bed bugs are unusual in the developed world, although they can be transported from other countries via suitcases or on clothes. They are unlikely, however, to bite only your scalp. If you find evidence of them, you will need to wash all bedding at hot temperatures and apply some kind of insecticide to your mattress.
If you suffer ongoing itching which is unpleasant but not unbearable, you may have caught lice; for further information see the page about head lice and nits.
Further reading: