Overview Show Tinea nigra is an infection that attacks the skin’s uppermost layers. It’s caused by a fungus called Hortaea werneckii.The fungus has also gone by the names of Phaeoannellomyces werneckii, Exophiala werneckii,and Cladosporium werneckii. This fungus is found in the soil, sewage, and decomposing vegetation of tropical or subtropical coastal regions. In particular, these areas include the Caribbean and the coast of South America. Tinea nigra is rare in the United States, but when it’s seen, it’s usually in the hot, humid climates of the Southeast. The fungus causes painless brown or black patches to grow on palms and feet. Sometimes other areas of the body, such as the neck and trunk, can be affected. Tinea nigra stems from infection with the fungus Hortaea werneckii. Direct contact with the fungus is necessary for transmission. Shaking the hand of someone with tinea nigra, for example, won’t spread the condition. The fungus can infiltrate skin via open wounds or cuts. It tends to thrive on wet, clammy, sweaty skin, which is why the palms of the hands and the soles of the feet seem to be common targets for the infection. Lesions typically appear about two to seven weeks after exposure to the fungus, according to research in Dermatology Online Journal. And while the condition can strike anyone, the journal Anais Brasileiros de Dermatologia reports it’s typically seen in women under the age of 20. Tinea nigra is largely painless and harmless, but it does produce a few symptoms. They include:
Your doctor will perform a physical exam and ask about your medical history as well as your recent travels. Tinea nigra can look like more serious skin conditions, such as malignant melanoma, a deadly form of skin cancer that can present as dark patches. Because of this, your doctor may want to scrape a sample of the lesion and send it to a lab for testing. In some cases, the lesion can be scraped entirely away and not require any further treatment. Tinea nigra affects the uppermost layers of skin. Because of this, it responds well to topical ointments and creams. These medications are applied directly to the skin. Your doctor may recommend medications like salicylic acid, urea, or benzoic acid. These speed cell turnover and cause skin to shed. Antifungal creams used for two to four weeks are also effective. In some cases, drying agents such as aluminum chloride are prescribed. Since the fungus that causes tinea nigra is found in soil, sewage, and rotting vegetation, the best way to prevent infection is to protect your skin. Wear shoes if you’ll be walking in the hot, humid regions where the fungus is found. If there’s any risk you’ll be touching vegetation — for instance, if you’ll be hiking, gardening, or planting — be sure to also wear gloves. Tinea nigra is a rare and harmless skin condition. With treatment, it usually resolves in a few weeks. It has no lasting side effects and is unlikely to recur unless you’re reexposed to the fungus. August 09, 2016 3 min read ADD TOPIC TO EMAIL ALERTS Receive an email when new articles are posted on Please provide your email address to receive an email when new articles are posted on . We were unable to process your request. Please try again later. If you continue to have this issue please contact . A 13-year-old boy presented to the pediatric dermatology clinic for evaluation of a black lesion on the back of his right heel that had been present for at least the past couple of weeks. Parents are concerned that it may have been present longer but has gone unnoticed. The lesion is asymptomatic to the patient, and he has continued his normal regimen of basketball practice three times per week.  Jenna L. Streicher Marissa J. Perman Parents deny that the lesion has significantly changed in size since presentation. The patient is otherwise healthy with no significant past medical history. The mother noted that she tried to clean the area, but that the spots remained. She is very concerned as she has a personal history of melanoma. On exam, the patient has violaceous-to-black, punctate macules on the posterior edge of the left plantar surface of the heel. The skin lines are uninterrupted. Figure 1. Violaceous to black, punctate macules on the posterior, medial edge of the left plantar heel. Source: Streicher JL Click the image to enlarge. PAGE BREAK Case Discussion:Talon noir (D) — French for “black heel” — is caused by shearing forces due to physical activities. The condition goes by many names including “calcaneal petechiae” and “posttraumatic punctate intraepidermal hemorrhage.” These forces cause rupture of intradermal blood vessels, which eventually deposit as punctate hemorrhages in the stratum corneum. This condition is commonly seen in adolescents and young adult athletes who are quickly changing directions, as seen in basketball, lacrosse, tennis or soccer. The lesions most commonly present on the heel due to this area being more susceptible to trauma and are usually unilateral. When found on the hands, the entity is called “tache noir.” Talon noir is asymptomatic and therefore often goes unrecognized. While the diagnosis is usually made clinically, it can be confirmed by using a #15 blade to pare the lesion, which often results in resolution. A hemoccult test can also be used to confirm the diagnosis, but is rarely necessary. The lesions will spontaneously resolve with time. The differential diagnosis of a dark lesion on the plantar surface of the heel includes a wart, dysplastic nevus, melanoma and tinea nigra. Due to the location on the plantar surface, a wart could be considered. Warts often have central black dots, which are dilated and thrombosed capillaries, and could be confused with talon noir. Warts, however, have a more verrucous surface change rather than the flat macules of talon noir. Warts also disrupt the skin lines. An acral nevus is also on the differential of a dark lesion on the foot. The concern for melanoma or atypical nevus is a common reason for presentation of talon noir to a physician, as in this case, due to its dark black color. Unlike talon noir, a melanocytic process would not resolve with paring of the lesion. Tinea nigra is a rare fungal infection caused by Hortaea werneckii that can present as brown-to-black macules commonly on the palmar or plantar surfaces. The fungus produces its own melanin-like pigment that leads to the characteristic brown appearance. This fungal infection is usually due to contamination from an environmental source such as soil or wood, but is uncommon in the United States. The lesions are asymptomatic and can be diagnosed by a potassium hydroxide scraping that reveals pigmented hyphae and oval spores. Another consideration could include traumatic implantation of a foreign material. However, this is more likely to be symptomatic. If concerned about foreign material, paring and a hemoccult test could be used, which would be negative. Talon noir presents commonly in athletes with black or violet-black macules located on the posterior plantar surface of the heels. Practitioners should be aware of this diagnosis in order to reassure parents that this is a benign process that does not require further work-up and will spontaneously resolve with time.
Disclosures: Streicher and Perman report no relevant financial disclosures. ADD TOPIC TO EMAIL ALERTS Receive an email when new articles are posted on Please provide your email address to receive an email when new articles are posted on . We were unable to process your request. Please try again later. If you continue to have this issue please contact . Why is there a black dot on my heel?Plantar warts look like calluses on the ball of the foot or heel. They may appear to have small pinholes or tiny black spots in the center. They are usually painful and may develop as a single wart or in clusters.
Why do I have a black spot under my foot?Tinea nigra infection: What to know. Tinea nigra is a very rare fungal infection. It causes brown or black patches to develop on the soles of the feet, the palms of the hand, or, on rare occasions, the torso. A type of yeast called Hortaea werneckii causes most tinea nigra infections.
What is the tiny black dot on the bottom of my foot that does not hurt?A plantar wart is a wart caused by a type of human papillomavirus, or HPV, which enters the body through tiny cracks in the skin on the bottom of the feet. Plantar warts: Are found on the sole of the foot. May contain tiny black dots.
What does melanoma look like on bottom of foot?Look for the signs of melanoma
Aside from looking like a changing mole, a melanoma on the foot can appear as a: Brown or black vertical line under a toenail. Pinkish-red spot or growth. New spot or growth where you injured your foot.
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Black spot on heel of foot under skin
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