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.
Undiagnosed dysphagia can also result in dehydration, malnutrition, and kidney failure.Some signs and symptoms of oropharyngeal dysphagia include difficulty controlling food in the mouth, inability to control food or saliva in the mouth, difficulty initiating a swallow, coughing, choking, frequent pneumonia, unexplained weight loss, gurgly or wet voice after swallowing, nasal regurgitation, and patient complaint of swallowing difficulty. When asked where the food is getting stuck, patients will often point to the cervical (neck) region as the site of the obstruction. The actual site of obstruction is always at or below the level at which the level of obstruction is perceived.The most common symptom of esophageal dysphagia is the inability to swallow solid food, which the patient will describe as becoming stuck or held up before it either passes into the stomach or is regurgitated. Pain on swallowing or odynophagia is a distinctive symptom that can be highly indicative of carcinoma, although it also has numerous other causes that are not related to cancer. Achalasia is a major exception to usual pattern of dysphagia in that swallowing of fluid tends to cause more difficulty than swallowing solids. In achalasia, there is idiopathic destruction of parasympathetic ganglia of the Auerbachs (Myenteric) plexus of the entire esophagus, which results in functional narrowing of the lower esophagus, and peristaltic failure throughout its length. Complications
Complications of dysphagia may include aspiration, pneumonia, dehydration, and weight loss. Cause
Following table enumerates possible causes of dysphagia:

Difficulty with or inability to swallow may be caused or exacerbated by usage of opiate and/or opioid drugs.