The highest incidence in the United States of America is in American boys of school age.There are three type of tinea capitis, microsporosis, trichophytosis, and favus; these are based on the causative microorganism, and the nature of the symptoms. In microsporosis, the lesion is a small red papule around a hair shaft that later becomes scaly; eventually the hairs break off 1–3 mm above the scalp. This disease used to be caused primarily by Microsporum audouinii, but in Europe, M. canis is more frequently the causative fungus. The source of this fungus is typically sick cats and kittens; it may be spread through person to person contact, or by sharing contaminated brushes and combs. In the United States, Trichophytosis is usually caused by Trichophyton tonsurans, while T. violaceum is more common in Eastern Europe, Africa, and India. This fungus causes dry, non-inflammatory patches that tend to be angular in shape. When the hairs break off at the opening of the follicle, black dots remain. Favus is caused by T. schoenleinii, and is endemic in South Africa and the Middle East. It is characterized by a number of yellowish, circular, cup-shaped crusts (scutula) grouped in patches like a piece of honeycomb, each about the size of a split pea, with a hair projecting in the center. These increase in size and become crusted over, so that the characteristic lesion can only be seen around the edge of the scab. Pathophysiology
From the site of inoculation, the fungus grows down into the stratum corneum, where it invades keratin.
However, concerns have been raised about the possibility of rare side effects like liver toxicity or interactions with other drugs; furthermore, the newer drug treatments tend to be more expensive than griseofulvin.On September 28, 2007, the U.S. Food and Drug Administration stated that Lamisil (Terbinafine hydrochloride, by Novartis AG) is a new treatment approved for use by children aged 4 years and older. The antifungal granules can be sprinkled on a childs food to treat the infection. Lamisil carries hepatotoxic risk, and can cause a metallic taste in the mouth. Epidemiology
Tinea capitis caused by species of Microsporum and Trichophyton is a contagious disease that is endemic in many countries. Affecting primarily pre-pubertal children between 6 and 10 years, it is more common in males than females; rarely does the disease persist past age sixteen. Because spread is thought to occur through direct contact with affected individuals, large outbreaks have been known to occur in schools and other places where children are in close quarters; however, indirect spread through contamination with infected objects (fomites) may also be a factor in the spread of infection. In the US, tinea capitis is thought to occur in 3-8% of the pediatric population; up to one-third of households with contact with an infected person may harbor the disease without showing any symptoms.The fungal species responsible for causing tinea capitis vary according to the geographical region, and may also change over time.