What Causes a Child to Itch All Over?

Atopic dermatitis is the most common cause of eczema. It is a common skin problem that affects up to 10 percent of Americans.

Atopic dermatitis usually occurs by the age of 5 — although dark-skinned people may be diagnosed later in life. It often begins with intensely itchy skin before a rash appears as scratching is what causes the rash. Atopic dermatitis can appear on any area of skin at any age, but there are certain areas where it's more common, including:

• On the cheeks of babies
• In the creases of elbows, knees, or buttocks and on the neck, wrists, and ankles in children who're aged 2 or older but haven’t reached adolescence
• Around the eyes and on the hands in adults

Atopic dermatitis can't be cured, but it can be treated. Finding a good treatment plan can help: 

• Reduce flareups
• Ease symptoms
• Prevent it from getting worse
• Prevent thickened skin
• Reduce the risk of infection

Treatment for atopic dermatitis focuses on following healthy skincare routines like applying moisturizer, avoiding triggers that cause reactions, and using medicines such as corticosteroid creams.

Some patients may also be given phototherapy — which involves exposing the skin to ultraviolet light.

Scabies is a common skin problem caused by tiny mites that burrow into your skin and lay eggs in the burrows they make. This causes a reaction that leads to a rash and itching, which is the first symptom of scabies. The condition is spread through being in close contact with someone who's infected. That’s why it often spreads in crowded places like daycares, dorms, and nursing homes.

Along with itching, other symptoms of scabies can include:

• Burrow tracks
• Blisters or bumps
• Scaly, thick, scabbed skin
• Irritability and poor feeding in young children

Scabies is treated with a medicated lotion that kills the mites. The lotion is applied all over the body, except for the mouth and eyes. It usually has to be left on for 8 to 12 hours and then rinsed off.

The treatment may need to be repeated in a week or two, and it may take 2 to 6 weeks after treatment before the rash and itching go away completely.

Urticaria is the medical term for hives. Like atopic dermatitis and scabies, urticaria can occur on any part of the body. The hives are produced by a skin reaction that causes welts to repeatedly appear and fade.

The hives may appear anywhere on the body and may be accompanied by swelling. Urticaria is often associated with an allergic reaction to triggers like:

• Nuts
• Chocolate
• Fish
• Tomatoes
• Eggs
• Berries
• Milk
• Medication
• Insect stings

Some people also develop urticaria from anything that makes them hot or sweaty. Physical urticarias can be caused by sunlight, cold, pressure, exercise, or vibration.

Hives that last longer than 6 weeks are called chronic urticaria. In most cases of chronic urticaria, there's no clear cause. The most common treatment for urticaria is an antihistamine.

Itching is one of the most common skin complaints in young children. In addition to the above, the following are some rarer causes of all-over itching in children.

Infection

Viral infections like chickenpox, fungal skin infections, or bacterial skin infections can cause itching. With chickenpox, children may have a fever, feel unwell, and have an extremely itchy rash.

Fungal infections are treated with an antifungal cream. If the infection doesn't improve with a cream, an oral antifungal medication may be needed. Bacterial skin infections may also be treated with antibiotics applied to the skin or with oral antibiotics if needed.

Systemic disease

More rarely, an itchy rash without any signs of skin problems can be caused by an underlying disease like:

• Chronic kidney failure
• Liver or gallbladder disease
• Endocrine disorders
• Drug reactions
• Myeloproliferative disorders
• Certain types of cancer

Anxiety

Chronic itching can also be associated with stress, anxiety, and other types of mood disorders.

Itching from other causes may even cause stress and anxiety, which can make itching even worse. The sensation is processed in the central nervous system, which consists of the brain and spinal cord. This may play a role in the relationship between itching and anxiety. 

There are medicines that can treat the itching-anxiety cycle, but they may have side effects. Some other ways to treat it include habit retraining, relaxation techniques, and cognitive behavioral therapy.