Disorders of the hair and their treatment before the 18th century

The basic science of hair biology: what are the causal mechanisms for the disordered hair follicle?

A hair disorder can be difficult to define, but patients are typically motivated to seek treatment when their hair growth patterns are significantly different from their cultural group or when growth patterns change significantly. The causes of hair disorders are many and varied, but fundamentally the disorder is a consequence of aberrant alterations of normal hair biology. The potential trigger factors for hair disorders can be attributed to inflammation, genetics, the environment, or hormones, of which the relative contributions vary for different diagnoses, between individuals, and over time. This article discusses the causal mechanisms for the disordered hair follicle.

Tinea capitis

Tinea capitis is a common dermatophyte infection of the scalp in children. Dermatophytes are classified into three genera; tinea capitis is caused predominantly by Trichophyton or Microsporum species. On the basis of host preference and natural habitat, dermatophytes are also classified as anthropophilic, geophilic and zoophilic. The etiological agents of tinea capitis usually fall in the first and last categories. In North America, tinea capitis is now predominantly due to Trichophyton tonsurans. During the past 100 years the most common North American organism for tinea capitis was initially Microsporum canis followed later by M. audouinii. In other parts of the world the epidemiology varies. Tinea capitis is generally observed in children over the age of 6 years and before puberty, with African Americans being the most affected group. Clinical presentations are seborrheic-like scale, 'black dot' pattern, inflammatory tinea capitis with kerion and tiny pustules in the scalp. The clinical diagnosis should be confirmed by mycological examination. Wood's light examination was of value in diagnosing tinea capitis due to M. canis and M. audouinii; however, it is not helpful in T. tonsurans tinea capitis. Asymptomatic carriers may be a significant reservoir of infection and spread of spores may also involve inanimate objects. Carriers may benefit from shampooing their hair. Treatment of tinea capitis requires an oral antifungal agent. The data from the use of terbinafine, itraconazole and fluconazole are promising and suggest that these agents have an efficacy similar to griseofulvin while shortening the duration of therapy. Both griseofulvin and the newer antimycotics have a favorable adverse-effect profile and are associated with high compliance.