tinea capitis

Author Bio
Kevin St. Clair
 

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 Key points
* Condition results in an infection of the scalp with a dermatophyte fungus, more commonly called ringworn.
* Condition caused by fungis from animal, human or soil, and is classified by how the fungus invades the hair shaft.
* Condition mostly affects children living in crowded conditions, but can be contracted by adults.
* Condition results in dry scaling, black dots, inflammed abscesses, and yellow crusts and matted hair.

Tinea capitis is a condition resulting in the infection of the scalp with a dermatophyte fungus, more commonly known as ringworm. Although common in children, Tinea capitis is less frequently seen in adults. The scalp can be infected with a number of fungi contracted from animals, humans or soil.

Tinea capitis is classified according to how the fungus invades the hair shaft. Ectothrix hair invasion is due to infection with M. canis, M. audouinii, M. distortum, M. ferrugineum, M. gypseum, M. nanum, and T. verrucosum. The fungal branches (hyphae) and spores (arthroconidia) cover the outside of the hair. Ectothrix infections can be identified by woods light (long wave ultraviolet light) examination of the affected area — the vet uses this to check your cats fur. The fur fluoresces green if infected with M. canis.

Endothrix invasion results from infection with T. tonsurans, T. violaceum and T. soudanense. The hair shaft is filled with fungal branches (hyphae) and spores (arthroconidia). Endothrix infections do not fluoresce with Woods light. Favus is caused by T. schoenleinii infection, which results in a honeycomb destruction of the hair shaft.

Tinea capitis is most prevalent between 3 and 7 years of age. It is slightly more common in boys than girls. Infection by T. tonsurans may occur in adults and are more common in crowded living conditions. The fungus can contaminate hairbrushes, clothing, towels and the backs of seats. The spores are long lived and can infect another individual months later. Animal-based infections are due to direct contact with an infected animal and are not generally passed from one person to another. Soil-based infections usually arise when working in infected soil but are sometimes transferred from an infected animal.

Tinea capitis may present in several ways such as dry and scaling  like dandruff but usually with moth-eaten hair loss, black dots the hairs are broken off at the scalp surface, which is scaly, smooth areas of hair loss, kerion  very inflamed mass, like an abscess, favus yellow crusts and matted hair, and in a carrier state with no symptoms and only mild scaling. Tinea capitis may result in swollen lymph glands at the sides of the back of the neck. Untreated kerion and favus may result in permanent scarring or bald areas. It can also result in an Id reaction, especially just after starting antifungal treatment.

Differential Diagnosis (Other conditions with similar appearance
Alopecia areata
Atopic Dermatitis
Drug eruptions
Id reaction (Autoeczematization)
Impetigo
Seborrheic Dermatitis
Syphilis
Trichotillomania

Diagnosis
Key Points
*Condition is diagnosed through scaly and bald patch combinations.
* Wood's light fluorescence can be helpful but not definitive.
* Diagnosis should be confirmed through clinical inspection by skin scrapings and hair pulled out by the roots.

Tinea capitis is suspected if there is a combination of scaly and bald patches. Wood's light fluorescence is helpful but not definitive as it only glows with certain types of fungus, and may glow for completely different reasons. The diagnosis of tinea capitis should be confirmed through clinical inspection by microscopy and culture of skin scrapings and hair pulled out by the roots.

Treatment
Key points
*Treatment should involves treating and testing all potential carriers, including family and friends and playmates/classmates.
*Antifungal Shampoos may be helpful.
*Treatment requires an oral antifungal agent.

If a child shows signs of tinea capitis, all family members should be tested and treated for signs of infection. Parents of classmates and playmates should also be informed so their families can also be tested and treated. Carriers may show no symptoms. Treatment involves antifungal shampoo, but if resistance remains, then oral treatment is recommended. Suitable Shampoos include 2.5% Selenium sulfide, 1% to 2% zince pyrithione, povidone-iodine, and 2% ketoconazole.

Tinea capitis requires treatment with an oral antifungal agent. However, some antifungal agents may be ineffective, and other agents may be required.