This is a condition of the hair in which dark-colored, gritty, pin-head-sized nodules are found irregularly distributed along the shaft of the hair. These growths resemble nits although smaller, and are so hard that they make a rattling sound when the hair is combed. It is usually confined to the scalps of women but occasionally affects the beards of men. The growths are darkly pigmented and the affected hairs relatively small in size.
Etiology and Pathology. This condition is rarely seen outside of Cauca in Columbia, South America. It is parasitic, due to a fungus growth consisting of spores, mycelia and filaments. It is probably mildly contagious and is evidently stimulated by the warmth of the atmosphere for the affection is more prevalent in the warmer valleys. The use of a mucilaginous oil or water by the native women in dressing their hair favors the development of the disease.
Diagnosis. This is readily made because of the stony hardness of the nodules and because the hair itself does not suffer as in trichorrhexis nodosa and monilethrix. The nits of pediculosis capitis may be easily differentiated by the other symptoms of that disease. Leptothrix occurs only on the axillary and genital hairs and is not due to a mycelium forming fungus.
Prognosis and Treatment. The former is good. Treatment, based upon culture experiments, consists in frequent washings with hot water to soften the growths and permit the penetration of hot mercuric chlorid solution (1:1000).