Nail fungus

from Wikipedia, the free encyclopedia
Classification according to ICD-10
B35.1 Tinea unguium
ICD-10 online (WHO version 2019)
Fungal nail infestation on both big toes

Nail fungus , also known as nail mycosis or onychomycosis , is an infection of the toenails or fingernails by dermatophytes (thread fungi), yeasts (sprouts) or molds (thread fungi). Internal (endogenous) disposition factors can be, for example, metabolic diseases, genetic defects that cause a particular susceptibility to onychomycosis, and immune defects . Patients with diabetes mellitus , circulatory disorders, nail eczema and nail psoriasis are particularly susceptible to fungal diseases. A warm, humid environment is also beneficial, so toenails are more often affected than fingernails. Longer antibiotic therapy can also be the cause . Nail fungus is not a serious disease, but it is a common one. Five to twelve percent of Europeans have dermatophytes in their nails, and the frequency increases with age.

root cause

Fungal nail diseases are mainly caused by dermatophytes. They are also called tinea unguium (singular: tinea unguis). Common genera are

Fungal nail diseases can also be triggered by yeasts ( Candida species ) or molds .

transmission

As with athlete's foot, the transmission of the fungal pathogens takes place via smear or contact infection either directly from person to person or via objects that are shared and not boiled or disinfected in between (drying wipes) or items of clothing (stockings, shoes). Infection is particularly possible wherever people go barefoot (e.g. swimming pool or sauna). Damp surroundings due to foot sweat, possibly inadequate foot disinfection and insufficient drying or too tight shoes promote the infection. Dermatophytes grow well in the damp warmth of long-worn shoes. Fungal nail infections are very often preceded by athlete's foot ( tinea pedum ), especially if this has not been treated or has not been treated adequately.

Diseases such as diabetes mellitus , circulatory disorders , inflammation of the nails and especially immune deficiency , for example due to old age, a disease such as AIDS or chemotherapy, weaken the body's defenses and thus increase the risk of infection.

There are two main types of nail fungal attack : a subungual invasion , in which the pathogens penetrate from below the nail ( subungual ), and a white superficial mycotic infection ( leukonychia trichophytica ), in which the pathogens come from the nail surface ( superficial ) and which results in a rather white discoloration of the nail.

Symptoms

In all different types of nail fungus infestation, the following symptoms usually occur together, especially in the advanced stage:

  • Dullness of the nail
  • white or yellowish discoloration on the edge of the nail
  • whitish, yellow or gray-brown spots in the nail
  • Thickening of the nail plate
  • Crumbling or fragility of the nail

Complications

Onycholysis of the nail (falling out) and destruction of the nail bed. Infestation of further nails.

Diagnosis

For an unequivocal diagnosis of a nail disease caused by fungi, some horn parts can be scraped off the conspicuous nail and examined directly under the microscope . In the case of a fungal infection, the hyphae are usually visible in the specimen and the diagnosis of nail fungus can be made immediately. For an exact identification of the pathogen species for the targeted selection of antimycotic active ingredients, for example, about three weeks of cultivation in cell culture is necessary.

However, since the fungal culture has poor sensitivity - depending on the laboratory, approx. 20–50% false negative results - molecular diagnostics have recently become more and more popular. The genetic makeup of the fungi is clearly determined in a sample using PCR . In the clinical validation study of a commercially available test co-developed by the Dresden University Hospital, a sensitivity of 87.3% and a specificity of 94.3% were demonstrated. In this respect, molecular diagnostics are clearly superior to microscopy and fungal culture. Further advantages are the traceability of dead pathogens, the detection of mixed infections and the short duration of the laboratory test of one to three days.

In the differential diagnosis , the nail fungus is to be distinguished from an isolated nail psoriasis , from so-called eczema nails and occasionally from a lichen planus of the nail organ. Furthermore, the possibility of congenital or acquired chronic nail dystrophy must be considered.

therapy

Therapy depends on the severity of the infection.

Local treatment

If less than 70% (according to another source, less than 50%) of the nail surface is affected in only one single nail, local therapy with antifungal agents is usually sufficient. There are ointments and nail varnishes available that are regularly applied to the nail. The nail may have to be softened or roughened beforehand.

In cases in which an exclusively external therapy (from the nail surface) is not promising, the nail can be atraumatic and therefore usually completely painless with a keratolytic , for example urea ointment, softened and removed, which takes about one to three weeks. If onychomycosis is severe, it is also possible to dissolve the affected nail with laser therapy . The affected nail and mostly also the top layer of the nail bed are usually painlessly evaporated by an erbium laser. In Germany, however, the costs of a laser treatment are not covered by the statutory health insurance companies.

Surgical nail removal by pulling the affected nail is no longer recommended, as the additional injury associated with it interferes with the healing process and can subsequently lead to abnormal nail growth.

After nail detachment or removal, local treatment ( local therapy ) of the nail bed and regrowing nail with antifungal cream or antifungal nail polish based on bifonazole , clotrimazole , ciclopirox or amorolfine is usually carried out .

Systemic treatment

In the case of extensive infestation, in special cases (more than three toenails are infected), but with a healthy liver , systemic therapy with the oral antimycotics griseofulvin , itraconazole , terbinafine or fluconazole must sometimes be carried out. It is important that the treatment lasts long enough, which usually lasts three to six months; Depending on the severity of the infection, up to twelve months or longer (interval therapy). In principle, oral therapy is significantly more effective than the use of local creams or varnishes, but it also involves risks and side effects, which is why the corresponding agents are subject to prescription.

The recurrence rate for purely systemic therapy is high (5–40%), which can be attributed to unfavorable anatomical conditions, slow nail growth in old age, poor immune status or poor patient compliance . Another possible cause of an unsuccessful therapy is that more and more types of fungus are becoming insensitive to antimycotics. Many of the drugs mentioned can also cause harmful side effects, such as a clinically significant increase in transaminases , which in turn reduces patient compliance. There is some evidence that a combination of systemic and topical agents is beneficial.

Laser therapy

In 2010 the FDA approved a laser for the direct irradiation of nail fungus for the first time. A pulsed infrared laser penetrates the nails infected with fungi, inactivating the existing fungal structures without damaging the nail. According to the manufacturer Pinpointe USA, Inc , 68 to 81% of patients report greater nail clearing after 6 to 12 weeks with a single treatment. After 12 months, 81% showed a “sustainable improvement” in clarification. In addition to the PinPointe laser , other lasers also have a foot mode , so that many dermatologists now offer this type of therapy. However, this form of treatment is usually not reimbursed by the statutory health insurance companies.

Naturopathy

Naturally , the affected part of the nail is sanded down and the area is dabbed with 5–25% vinegar (or vinegar essence ) over many weeks in the morning and evening . The fungus needs an alkaline environment and slowly regresses through the vinegar treatment while the nail grows back.

Portuguese researchers were able to show that even in low concentrations lavender oil kills various yeast and filamentous fungi that can cause skin and nail fungal diseases in humans. Other essential oils are also used in alternative medicine.

A common home remedy are menthol-containing ointments ( Tiger Balm , Vaporub ), for which there is only weak evidence of effectiveness. Topical application of tea tree oil has also been reported to be successful due to its fungicidal effect, among other things . However, neither regular nor alternative topical treatments (external treatments) can penetrate the nail deep enough to help against stronger fungal attack.

General prevention

To avoid a fungal nail infection, all measures to prevent athlete's foot or an immediate and consistent treatment of already existing athlete's foot are essential. A warm, humid climate in the shoe should be avoided. To protect against embrittlement, the skin and nails must be protected by regularly applying a suitable cream. Shoes that are as open and breathable as possible, which do not constrict the toes, and stockings made of moisture-wicking material are required.

To prevent renewed infection (reinfection) during and after treatment of the nail fungus, general hygienic measures such as disinfecting the stockings and drying wipes that have been used up to now are absolutely necessary.

literature

  • Peter Altmeyer, Martina Bacharach-Buhles: Encyclopedia of Dermatology, Venereology, Allergology, Environmental Medicine. Volume 2: M-Z. 2nd, completely revised edition. Springer, Berlin / Heidelberg 2010, ISBN 978-3-540-89543-5 , chapter: Tinea unguium (online) .

Individual evidence

  1. ↑ a b c Siegfried Bäumler: Medicinal Plant Practice Today. Volume 2: Recipes and application. 2nd Edition. Elsevier + Urban & Fischer, Munich 2013, ISBN 978-3-437-57273-9 , p. 409 ( limited book review on Google Books ).
  2. ^ A b Irene Weitzman, Richard S. Summerbell: Dermatophytes. In: Clinical Microbiology Revies. April 1995, Vol. 8, No. 2, pp. 240-259, PMID 7621400 , PMC 172857 (free full text).
  3. ^ A b c Peter Altmeyer, Martina Bacharach-Buhles: Encyclopedia of Dermatology, Venereology, Allergology, Environmental Medicine. Volume 2: M - Z. Section: Tinea unguium.
  4. ↑ Advice on nail fungus: Nail fungus: symptoms . On: ratgeber-nagelpilz.com ; Retrieved October 20, 2013.
  5. ↑ RC Summerbell, E. Cooper, U. Bunn, F. Jamieson, AK Gupta Onychomycosis: a critical study of techniques and criteria for confirming the etiologic significance of nondermatophytes. In: Medical mycology. (Med Mycol) Feb. 2005, Volume 43, Ne. 1, pp. 39-59, PMID 15712607 .
  6. ↑ L. Mehlig, C. Garve, A. Ritschel, A. Zeiler, W. Brabetz, C. Weber, A. Bauer: Clinical evaluation of a novel commercial multiplex-based PCR diagnostic test for differential diagnosis of dermatomycoses. In: Mycoses. Jan. 2014, Volume 57, No. 1, pp. 27-34, doi: 10.1111 / myc.12097 .
  7. ↑ TINEA Unguium - Onychomycosis . On: derma.de - Dermatology working group on the Internet of the German Dermatological Society (DDG), accessed on June 28, 2012.
  8. ↑ a b Peter Altmeyer : Therapielexikon Dermatologie und Allergologie. Springer, Berlin / Heidelberg 2005, ISBN 3-540-23781-X , p. 894.
  9. ↑ Nail fungus: varnish, cream or tablets? On: Gesundheitsinformation.de (consumer website of the IQWIG ) from January 14, 2015, accessed on August 29, 2015.
  10. ↑ Eckart Haneke: Nail fungus - Often a side effect of other diseases . In: Pharmazeutische Zeitung online - Archive, accessed on June 14, 2016.
  11. ^ Antibiogram yeasts . From: laborlexikon.de , accessed on June 27, 2012.
  12. ^ P. Rodgers, M. Bassler: Treating onychomycosis . In: American family physician (Am Fam Physician) . tape 63 , no. 4 , 2001, p. 663-672, 677-678 , PMID 11237081 ( aafp.org ).
  13. ↑ PinPointe FootLaser receives FDA clearance for the treatment of nail fungus (onychomycosis) . At: marketwire.com - News Room, October 25, 2010; last accessed on May 5, 2014.
  14. ↑ M. Zuzarte, MJ Goncalves et al. a .: Chemical composition and antifungal activity of the essential oils of Lavandula viridis L'Her .. In: Journal of Medical Microbiology. 60, 2011, pp. 612-618, doi : 10.1099 / jmm.0.027748-0 .
  15. ^ A. Angioni, A. Barra, V. Coroneo, S. Dessi, P. Cabras: Chemical composition, seasonal variability, and antifungal activity of Lavandula stoechas L. ssp. stoechas essential oils from stem / leaves and flowers. In: Journal of agricultural and food chemistry. Volume 54, Number 12, June 2006, pp. 4364-4370, doi : 10.1021 / jf0603329 , PMID 16756368 .
  16. ↑ M. Zuzarte, MJ Gonçalves, C. Cavaleiro, AM Dinis, JM Canhoto, LR Salgueiro: Chemical composition and antifungal activity of the essential oils of Lavandula pedunculata (Miller) Cav. In: Chemistry & biodiversity. Volume 6, Number 8, August 2009, pp. 1283-1292, doi : 10.1002 / cbdv.200800170 , PMID 19697345 .
  17. ↑ R. Derby, P. Rohal et al. a .: Novel treatment of onychomycosis using over-the-counter mentholated ointment: a clinical case series. In: Journal of the American Board of Family Medicine. (JABFM) Volume 24, No. 1, Jan-Feb 2011, pp. 69-74, ISSN  1557-2625 , doi: 10.3122 / jabfm.2011.01.100124 , PMID 21209346 .
  18. ^ Charles Patrick Davis: Treatment of Onychomycosis . In: emedicinehealth.com accessed on June 2, 2014.