Black piedra

Black piedra /nodular trichomycosis, nodular trichosporia/ is an infectious disease that is caused by mold fungi and is characterized by the appearance of small, solid black nodules, mainly on the scalp.

The disease is conditionally endemic in countries with a warm and humid climate such as those located in Central and South America, African countries, the island of Madagascar and in countries in East Asia /India, China, Thailand/.

Women are more prone to this type of fungal infection. Girls and women between the ages of 25 and 40 are most often affected. Among men, children and the elderly, the disease is extremely rare.

Nodular trichomycosis is characterized by a long course, as not only the cases in which it passes into a chronic stage. With correctly assigned treatment, the prognosis is favorable.

What are the causes?

The cause of the disease is Piedraia hortae.

The source of infection is still unknown. Spores of the fungus are found on the fur of animals, in ponds with stagnant water, in the soil.

In addition to humans, apes also suffer from nodular trichomycosis.

The following contribute to the development of the disease:

• High temperature and humidity of the environment;

• Failure to observe the rules of personal hygiene, especially in areas where this type of fungal infection is endemic;

• Washing hair in ponds with stagnant water;

• Wearing tight barrettes that pinch the hair;

• Rubbing different oils into the scalp;

• Contamination of hair with powdered sugar or flour;

• Prolonged contact with the causative agent of the infection;

• Weakening of immunity, for example in:

– Frequent illness from acute respiratory viral infections;
– Chronic diseases of the internal organs;
– Diseases of the endocrine system – hypothyroidism, diabetes mellitus;
– Oncological pathologies;
– Transplantation of organs;
– Permanent or long-term intake of hormonal preparations, antibiotics or chemotherapeutic agents;
– Infection with the HIV virus or AIDS;
– Hypovitaminosis;


According to the localization of the infectious process, black piedra is subdivided into:

• The moustache;
• The beard;
• The head or more precisely the scalp;

According to the way of proceeding, they are distinguished:

• Acute course;
• Chronic course;

What are the symptoms?

Dense nodules of dark color, oval or spindle-shaped, 1-2 mm in diameter begin to form on the hair and less often on the hairs of the mustache and beard. The number of knots on one hair can reach 50 or more.

The nodules tightly “surround” the hair and literally stick to it, sometimes there are also tendencies for the fusion of the nodules. At the same time, a shell is formed around the hair, which reaches 3-5 mm in length.

When brushing or combing the affected hairs or hair, a characteristic cracking sound is heard.
The hair becomes brittle and begins to drip, which without treatment can lead to severe baldness.

Treatment of black piedra

Preparations with local action containing antifungal agents such as ketoconazole, clotrimazole, lamisil and exoderil are used as drugs for this disease.

Shampoos also containing antifungal agents are also effective. The duration of the treatment course is determined by the attending physician in each individual case. If the beard and mustache are affected, it is necessary to shave them.

If the disease develops in pregnant women, nursing mothers or infants, the old treatment methods can be used:

• Application to the affected hair of a 1 in 1000 solution of warm mercuric chloride;
• Frequent brushing with a comb;
• Subsequently treatment with household soap.

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