If your toddler develops a rash it can leave you wondering about the cause and how to treat it. Infections, viruses and allergic reactions are only a few things that cause rashes of the scalp. Most rashes can easily be diagnosed and treated by your pediatrician; however, if the cause is unknown, you may be referred to a dermatologist.

Ringworm of the scalp, also known as tinea capititis, is a common fungal infection for children. According to New York State, the early ringworm resembles a small pimple, but progresses into larger scaly patches of temporary baldness. A child with ringworm will often have flaking of the scalp. Since dandruff is uncommon for toddlers, this is often a good indicator of ringworm.

Cellulitis is another infection that can cause scalp rash. This potentially life threatening condition occurs when bacteria enters the skin. According to MayoClinic.com, the most common bacteria to cause cellulitis are staphylococcus and streptococcus. Areas where there are cracks in the skin, such as cuts, can allow bacteria to enter the body, and the symptoms are usually red, swollen skin that is warm to touch.

According to the American Academy of Pediatrics, or AAP, roseola is a virus that is so common that almost all children get it before kindergarten. It starts with a high fever for 3 to 7 days, but when the fever disappears, a pink-colored rash develops on the body. Once the fever goes down, your child should no longer seem ill.

Chicken pox is another virus that can cause a rash. Chicken pox causes extremely itchy blisters that often cover the entire body. The blisters break and turn into open sores, which then scab-over as they heal. Having your toddler vaccinated for chicken pox can reduce the risk of this virus.

According to the AAP, atopic dermatitis is a chronic condition of the skin that has small bumps, redness, and itchiness that commonly affects the cheeks, forehead and scalp. The cause of eczema is unknown; however, it is most often diagnosed in children with a family history of eczema or allergies.

An allergic reaction could also cause a rash on the scalp. For instance, your child’s scalp may become irritated by an ingredient in a new shampoo or a laundry detergent you use to wash the bedding.

Cradle cap is uncommon for toddlers and most often occurs in newborns; however, it’s still possible for toddlers. With cradle cap, the scalp has a layer of yellowish colored crusty scales. According to the AAP, you should not wash a child’s scalp more than once per week with shampoo if he has cradle cap. This condition will normally disappear on its own.

Head lice can also cause a rash-like appearance on the scalp of a toddler. According to “The Baby Book,” the lice themselves are harmless; however, the itching can cause redness of the scalp.

If you child has a scalp rash, it is a good idea to consult with your child's pediatrician to determine the cause of the rash. The treatment for infections will depend on the cause. For instance, ringworm would be treated with anti-fungal medication, and cellulitis would be treated with an antibiotic. If your child’s pediatrician determines a virus is the cause, then there will be no cure other than letting the virus run its course. However, a doctor may recommend a topical treatment to help relieve itching. If your child begins a treatment regimen and the condition becomes worse, contact the pediatrician or a local hospital’s emergency room immediately.