Itching of the scalp is a symptom that we all experience every now and then. It is usually short-lived, quickly relieved with scratching and may not recur again immediately thereafter. In these cases it is not a cause for concern and most people do not even give it a second thought. However, there are instances when an itchy scalp becomes a significant problem and may be related to a medical condition that requires proper treatment.
The hair traps dust and microbes from the environment all day, in addition to being inundated with its own natural oils from the scalp as well as dead skin cells. Factor in the plethora of hair care produces that is part of modern life and there is a mix of substances that can easily irritate the scalp. It may not be as much of a problem if the hair and scalp are washed regularly. This means a thorough wash with a mild shampoo at least 2 to 3 times a week if not more often. Regular washing will ensure that the irritants on the hair and scalp are removed.
However, excessive washing may be just as much of a problem. Not only does excessive washing strip the natural oils and contribute to a dry scalp but it can also damage the scalp if strong shampoos are used regularly and may even increase the risk of infections. The key is to find the balance in how frequently you should wash your hair and scalp. People with braids or hair extensions may find it difficult to wash their hair frequently but if an itchy scalp is the problem, it is then necessary to forgo fashion for good personal hygiene.
Dryness of the scalp is another factor that contributes to an itchy scalp. As mentioned above, excessive washing particularly with strong shampoos can contribute to scalp dryness. Other factors include hair care products developed for oily hair, some hair styling gels and even environmental factors like wind and heat. Many of us do not realize that our scalp is just as prone to drying and sunburn from intense sun exposure as skin elsewhere on the body. The presence of hair does not necessarily offer significant protection.
A dry scalp does not mean that you should avoid washing your hair. Rather try to identify the cause of the dryness and use hair care products that can help with minimizing dryness while ensuring proper cleansing. The dryness may also be a symptom of underlying skin and scalp diseases which should be medically treated in order for the dry scalp to resolve. Excessive dryness leading to flaking skin from the scalp is often referred to as dandruff.
While unwashed hair and a dry scalp are among the more common causes of an itchy scalp, there are several skin diseases that can also affect the skin on the head. Acne vulgaris is one of those conditions. Most of us know that acne tends to affect the face, chest, shoulders and back. These are areas with greater natural skin oil (sebum) production due to increased oil-producing glands (sebaceous glands). However, the scalp also produces more oil and is therefore prone to acne. Coupled with bacteria, dead skin and oil plugs pimple formation on the scalp can easily occur.
- Poor hygiene does not cause acne but frequent washing can help.
- Use prescribed shampoos that have a drying effect on the scalp if it is oily.
- Certain antimicrobial shampoos may be beneficial.
- Speak to a dermatologist about a systemic treatment for acne, like isoretinoin, rather than just topical measures.
Picture of back acne
Another fairly common yet often unknown scalp condition is a fungal infection of the skin. It is the same type of fungal infection that commonly affects the feet to cause athlete’s foot (tinea pedis) and jock itch (tinea cruris). A fungal scalp infection (tinea capitis), often referred to as a scalp ringworm, can be caused by a number of different species of fungi that have a predilection for human skin (dermatophytes). Some may cause additional symptoms like focal hair loss. These infections are easily spread at salons and are a particular risk for people who shave their head. It is more common in hot tropical environments.
- Avoid sharing contaminated hair care items like combs.
- Antifungal shampoos are very effective in combating the infection.
- Severe cases may require systemic treatment with antifungal oral medication.
Picture of scalp ringworm (Dermatology Atlas Brazil)
Contact Dermatitis on the Scalp
Substances that act as irritants or allergens that come into contact with the scalp can cause inflammation of the skin (dermatitis). Itching is one of the major symptoms. This condition is known as contact dermatitis and there are two types – irritant contact dermatitis and allergic contact dermatitis. In irritant contact dermatitis, the substance irritates the scalp and can even be everyday substances like sweat or water that is on the scalp for too long. With allergic contact dermatitis, a person is sensitive to certain substances (allergens) that cause allergic reactions like in hair dye allergies.
- Stop using or minimize exposure to substances that have been identified as irritants and allergens.
- Washing of the hair and scalp on a regular basis helps remove irritants like sweat or other substances trapped from the environment.
- Topical applications containing medication like corticosteroids are only needed for severe cases.
Infection of the hair follicles is known as folliculitis. It can occur anywhere on the body but is more likely to affect areas where there is more hair, like the scalp and armpits. Folliculitis is caused by a number of different bacteria like Staphylococcus aureus. It causes the formation of red, inflamed, pus-filled lesions at the base of the hair shaft. Itching, burning and even pain with or without a discharge are some of the symptoms and in severe and persistent cases there may even be hair loss.
- Antimicrobial shampoos may help with the treatment and prevention.
- Antibiotics are often necessary to eradicate the bacteria causing the infection.
- Regular washing of the hair and avoiding hair care products can help.
Picture of scalp folliculitis
Head lice infestation occurs when a tiny insect Pediculosis capitis settles on the scalp and feeds off human blood. It is a fairly common type of parasitic infestation particularly among children. It quickly spreads among family members and due to the high recurrence rate it should be treated aggressively. The head lice differs from lice elsewhere on the body. However, the treatment of head lice is largely the same as it is for body lice and pubic lice (“crabs”).
- OTC shampoos containing pyrethrin or permethrin.
- Prescription medication like malathion and lindane.
- Oral medication like ivermectin.
Picture of a head louse
Seborrheic dermatitis is a scalp condition where there is excessive sebum (oil) production leading to the formation of yellow crusts. It is one of the possible causes of dandruff along with dry skin, fungal infections and other scalp conditions. Seborrheic dermatitis appears to be an immune-related condition where the immune system reacts to the presence of the Malassezia species of the fungi on the scalp. It is not a fungal infection but rather an abnormal immune response leading to scalp inflammation.
- Hydrocortisone creams or shampoos to reduce inflammation.
- Antifungal medication and sometimes antibiotics.
- Medication to modulate the immune system.
Picture of seborrheic dermatitis on the scalp
Other Possible Causes
- Atopic dermatitis (eczema)
- Urticaria (hives)