One of the most common sites for a fungal infection in the scalp, the skin on the top of the head that is usually laden with hairs. Tinea capitis is a fungal infection of the scalp skin caused by dermatophytes. Since dermatophytes cause a typical red ring-like rash, it is often referred to as scalp ringworm. However, it is important to note that a scalp ringworm has no involvement with any parasitic worm of any sorts. The fungus consumes the skin cells and the base of the hair in many instances thereby making it one of the most important infectious causes of hair loss.
What causes tinea capitis?
Causes of Scalp Ringworm
A scalp ringworm is caused by fungi, not worms. Although it is possible for yeasts to cause a fungal infection of the scalp, the vast majority of cases are due to an infection with dermatophytes. The term dermatomycosis is used to describe skin fungal infections by these skin-specific fungi known as dermatophytes.
The scalp is a common site for various reasons. Fungi thrive in environments that are warm, moist and dark. The skin is composed of protein-laden dead skin cells on the outermost layers providing sufficient nutrition for the fungi. The hair on the head and the heat build up with the contribution of perspiration ensures that the fungi have all the necessary factors for its survival, namely the darkness, warmth and moisture.
Scalp Ringworm Fungi Species
Tinea capitis is primarily caused by Trichophyton and Microsporum species of fungi. These are the most common types of fungal species responsible for almost all skin fungal infections. Some Tricohphyton species consume the shaft hair from inside out and this weakens the strands of hair to such an extent that it breaks off.
Other Trichophyton species and all Microsporum species may consume the hair shaft from outside only and although hair loss is possible in these cases, it is unlikely to lead to breakage. Then there is one type of Trichophyton species of fungus that destroys the hair in a honeycomb pattern, which is both unusual and uncommon.
How is tinea capitis transmitted?
Spread of Scalp Ringworm
Fungi can be transmitted by direct contact and spread from person-to-person. Some species are known as zoophilic fungi and may be spread from animals (usually pets) to humans. It is important to note that contact with fungi may occur incidentally on a regular basis but this does not mean that every exposed person will develop tinea capitis.
Fungi, like most microbes, infect an area when the normal defense mechanisms are compromised or the conditions exist for its growth. For example, very dry skin or breaks in the skin compromises its barrier function. Not washing the hair frequently or excessive washing, wearing tight braids (dreadlocks) and using harsh hair care products may also increase the likelihood of infection. These predisposing factors increase the likelihood of a scalp ringworm infection.
Sharing personal hair care items with an infected person, like combs and hairbrushes, using caps or hats worn by the infected person and even contact with the hands after an infected person scratches the head can spread a scalp ringworm. It tends to spread more frequently in day care centers and schools where children are not aware of limiting close physical contact.
What does tinea capitis look like?
Symptoms of Scalp Ringworm
Tinea capitis does not always cause obvious visible symptoms. Sometimes it is so mild that a person does not realize that they have a scalp ringworm. At other times a person may experience an itchy scalp and what appears to be mild dandruff without any further symptoms. There may be no hair loss or clearly visible patches of infected skin on the scalp.
Typically, tinea capitis presents with the following signs and symptoms :
- Dry scaly skin on the scalp.
- Red inflamed patches which feels spongy and tender when very inflamed.
- Loss of hair as the shaft breaks. Tiny spots similar to the natural hair color may be the only remnants of the remaining shaft.
- Crusty yellow patches intertwined with matted (tangled) hair.
- Abscess on the scalp with secondary bacterial infections at the site.
- Kerions are very swollen patches with tiny blisters (pustules) oozing fluid from the site. It is seen in very severe scalp ringworm infections.
Pictures of Scalp Ringworm
How is tinea capitis diagnosed?
Tests for Scalp Ringworm
Tinea capitis is diagnosed during clinical examination and visualization of the scalp. Ideally it should be evaluated by a dermatologist or trichologist using a Wood’s lamp. Sometimes a small sample of the skin through scraping or biopsy can be collected and examined under a microscope of a potassium hydroxide wet mount. This will conclusively confirm the diagnosis of tinea capitis. Culture of the fungus may further assist in identifying the exact species responsible for the scalp ringworm infection.
How is tinea capitis treated?
Treatment for Scalp Ringworm
Antifungals are used to treat scalp ringworm. Topical antifungals are very effective for treating any skin fungal infection and for a scalp ringworm, it is usually in the form of antifungal shampoos which may also contain zinc and selenium. These shampoos should be used for up to 2 to 3 months after the infection resolves and the area heals. Topical steroids may also be helpful in reducing the inflammation but should be avoided at the outset.
A scalp ringworm usually does not require systemic therapy with oral antifungal agents (tablets or capsules) in every case. However, when necessary then oral antifungal agents griseofulvin and terbinafine are very effective in eradicating the fungal infection altogether. These tablets and capsules should be used for between 1 to 2 month for the maximum effect.
Antibiotics may be necessary for any secondary bacterial infection of the scalp. However, these drugs are not effective in eradicating a fungus.
What is the natural treatment for tinea capitis?
Natural remedies for Scalp Ringworm
A widely used herbal product for superficial fungal infections is tea tree oil (Melaleuca officinalis). It is derived from the tea tree plant and the oil can be applied directly to the skin or scalp. However, it has a very strong drying effect and can irritate the skin further so ideally tea tree is diluted in another oil. Tea tree creams and shampoos are available in diluted forms ranging from 1% to 10% concentrations or even higher. While it is an effective antifungal agent, tea tree needs to be used for a long period of time. It should never make contact with the eye and has to therefore be used in low concentrations in children or avoided altogether in younger patients.