Occupational hazards of human nail dust

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The use of podiatry drills, in the absence of engineering controls and personal protective equipment, is an occupational hazard to the healthcare provider. Nail dust collected during foot care procedures performed in office settings has been found to contain keratin, keratin hydrolysates, microbial debris, and viable fungal elements, including dermatophytes (most commonly Trichophyton rubrum ) and saprotrophs. [1] [2] Exposure to nail dust and the associated risk will vary with the policies and practices in place, the type of podiatry drill used, therapy technique, frequency of procedures, personal protective equipment utilized and the use of ventilation systems.

Contents

Nail dust generation

Healthcare providers may use podiatry drills on onychauxic (thickened) nails of patients to alleviate or eliminate pain, prevent or treat subungual ulcerations, allow better penetration of topical antifungal agents, or improve cosmesis, all in effort to improve the patient's quality of life. [3] [4] In a study conducted by Miller, 65% of respondents reported routinely drilling thickened toenails. [5] However, the improved effectiveness of antifungal drugs such as itraconazole and terbinafine reduces the need to drill these infected nails. [6]

Podiatry drills have a mechanical rotating burr that can be set at a range of speeds usually up to 12,000 rpm and may or may not have an integrated local ventilation extraction system. [7] Even with the most effective dust extractors, the electric nail debridement process is not totally risk free because the extractors range from 25% - 92% effective in reducing airborne particles. [8] [9] While the large particles settle out to the floor, varying amounts of smaller particles remain suspended and are inhaled by or adhere to the practitioner and clinical environment. [2] The particle sizes range from 0.1 to 100 um and 86% of these particles are less than 5 um in diameter and therefore capable of entry into the alveoli. [2]

Health implications

Fungi are ubiquitous organisms that play a vital role in decomposing organic matter. Many species of fungi live on the human body and some will infect nails causing a condition called onychomycosis. There are oral and topical antifungal therapies for this condition, however, in some instances cutting, filing, or abrading the nail may be necessary to improve cure rates. [10] Thickened nails caused by injury, infection, diabetes, psoriasis, or vascular disease may require the use of a mechanical therapy, which can expose the healthcare worker to microbial dust.

Exposure to nail dust was first discussed and described in the literature as an occupational hazard in the early 70's. [11] In 1975, two female chiropodists were diagnosed with allergic hypersensitivity to nail dust. [12] Since that time, there have been a number of occupational-related complaints pertaining to airborne nail dust exposure and efforts have been made to study the podiatric professionals to determine related symptoms. [4] Biological dust from the hand and foot care procedures may deposit in the conjunctiva, nose, and throughout the respiratory tract. [12] The local irritation of these areas can lead to conjunctivitis, itching, tearing, rhinitis, sneezing, asthmatic attacks, bronchitis, and coughing. [12] [13]

The literature suggests that nail dust can be a respiratory sensitizer, which is defined as a substance that when breathed in can trigger an irreversible allergic reaction in the respiratory system. [4] [14] Sensitization does not usually take place immediately, but rather after months or years of exposure to the agent. Once sensitized, even the smallest amount of the substance can trigger asthma, rhinitis, or conjunctivitis that may exhibit the following symptoms: coughing, wheezing, chest tightness, runny or stuffy nose, and watery or prickly eyes. [4] Millar found that within the podiatry profession there is four times the national prevalence of asthma. [15] Hypersensitivity reactions are the most probable disposition for healthcare workers inhaling nail dust, although more serious lung pathology can not be ruled out [9] [16] [17]

It is widely known and accepted that fungi will induce asthma, but it is estimated that only 10% of the population has allergic antibodies to fungal antigens, and half of them, that is 5% of the population, would be asymptomatic, further complicating the link between the fungal dust and troubling symptoms. [18] Trichophyton rubrum is the most common fungal cause of nail dystrophy. [16] Studies conducted in England found that the prevalence of trichophyton rubrum antibodies in podiatrists ranged from 14%-31%. [16] [19] This is evidence that the podiatrist is heavily exposed to trichophyton rubrum as observed in increased precipitating antibodies compared to the general population. [8] [16] [19] It has been suggested that absorption of trichophyton fungal antigens can give rise to immunoglobulin E (IgE) antibody production, sensitization of the airways, and symptomatic asthma and rhinitis. [1] [13] [16] [20]

Nail work requiring clipping and drilling is also a potential cause for ocular injury and infection to the podiatrists, podiatric staff, and patients that are exposed to nail fragments and high-speed drills used for grinding. [18] [21] Possible ocular hazards result from exposure to foreign bodies, allergens, bacteria, viruses, fungi and protozoa that can be introduced at the time of eye trauma, or enter as a consequence of damage to the ocular structures; permitting the entry of opportunistic infection. [18] The high-speed rotation of podiatry drill burrs potentially expose the healthcare worker to aerosols containing bloodborne pathogens such as Hepatitis B, Hepatitis C, or HIV. [22] Davies et al. surveyed podiatrists and found that 41% of them complained of eye problems, particularly soreness, burning, itching and excess lacrimation. [16]

A 1990 case illustrates the potential for ocular trauma to the healthcare provider: A podiatrist suffered a lacerated cornea when hit by a metallic shard from the grinding bit or by a fragment from the patient's toenail. The podiatrist reported fleeting periods of blurriness for several months following the incident. The healthcare worker's exposure to foreign bodies is not well documented in the literature like they are with dental staff using similar equipment; however, many of these incidents are certain to go unreported. The healthcare provider's risk of injury during nail care, however slight, warrants the use of simple and inexpensive preventative measures. [17]

Infections in the patients

There have been numerous accounts of patients with trichophyton fungal infections and associated asthma, which further substantiates the likelihood of respiratory disease transmission to the healthcare provider being exposed to the microbe-laden nail dust. [1] [23] In 1975, a dermatophyte fungal infection was described in a patient with severe tinea. The resulting treatment for mycosis improved the patient's asthmatic condition. [24] The antifungal treatment of many other trichophyton foot infections has alleviated symptoms of hypersensitivity, asthma, and rhinitis. [1] [23] [24] [25] [26] [27] [28]

Control measures

Chronic exposure to human nail dust is a serious occupational hazard that can be minimized by not producing such dust. Best practice is to avoid electrical debridement or burring of mycotic nails unless the treatment is necessary. [17] When the procedure is necessary, it is possible to reduce exposure by using nail dust extractors, local exhaust, good housekeeping techniques, personal protective equipment such as gloves, glasses or goggles, face shields, and an appropriately fitted disposable respirators to protect against the hazards of nail dust and flying debris. [5] [7] [9]

See also

Related Research Articles

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Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include red eyes, an itchy rash, sneezing, coughing, a runny nose, shortness of breath, or swelling. Note that food intolerances and food poisoning are separate conditions.

An allergen is an otherwise harmless substance that triggers an allergic reaction in sensitive individuals by stimulating an immune response.

<span class="mw-page-title-main">Podiatrist</span> Medical professional devoted to the medical treatment of disorders of the foot

A podiatrist is a medical professional devoted to the treatment of disorders of the foot, ankle, and related structures of the leg. The term originated in North America but has now become the accepted term in the English-speaking world for all practitioners of podiatric medicine. The word chiropodist was previously used in the United States, but it is now regarded as antiquated.

<span class="mw-page-title-main">Hypersensitivity</span> Overreaction of the immune system to an antigen

Hypersensitivity is an abnormal physiological condition in which there is an undesirable and adverse immune response to an antigen. It is an abnormality in the immune system that causes immune diseases including allergies and autoimmunity. It is caused by many types of particles and substances from the external environment or from within the body that are recognized by the immune cells as antigens. The immune reactions are usually referred to as an over-reaction of the immune system and they are often damaging and uncomfortable.

<span class="mw-page-title-main">Nail disease</span> Medical condition

A nail disease or onychosis is a disease or deformity of the nail. Although the nail is a structure produced by the skin and is a skin appendage, nail diseases have a distinct classification as they have their own signs and symptoms which may relate to other medical conditions. Some nail conditions that show signs of infection or inflammation may require medical assistance.

<span class="mw-page-title-main">Rhinitis</span> Irritation and inflammation of the mucous membrane inside the nose

Rhinitis, also known as coryza, is irritation and inflammation of the mucous membrane inside the nose. Common symptoms are a stuffy nose, runny nose, sneezing, and post-nasal drip.

<span class="mw-page-title-main">Athlete's foot</span> Skin infection caused by fungus

Athlete's foot, known medically as tinea pedis, is a common skin infection of the feet caused by a fungus. Signs and symptoms often include itching, scaling, cracking and redness. In rare cases the skin may blister. Athlete's foot fungus may infect any part of the foot, but most often grows between the toes. The next most common area is the bottom of the foot. The same fungus may also affect the nails or the hands. It is a member of the group of diseases known as tinea.

<span class="mw-page-title-main">Type I hypersensitivity</span> Type of allergic reaction

Type I hypersensitivity, in the Gell and Coombs classification of allergic reactions, is an allergic reaction provoked by re-exposure to a specific type of antigen referred to as an allergen. Type I is distinct from type II, type III and type IV hypersensitivities. The relevance of the Gell and Coombs classification of allergic reactions has been questioned in the modern-day understanding of allergy, and it has limited utility in clinical practice.

Dermatophyte is a common label for a group of fungus of Arthrodermataceae that commonly causes skin disease in animals and humans. Traditionally, these anamorphic mold genera are: Microsporum, Epidermophyton and Trichophyton. There are about 40 species in these three genera. Species capable of reproducing sexually belong in the teleomorphic genus Arthroderma, of the Ascomycota. As of 2019 a total of nine genera are identified and new phylogenetic taxonomy has been proposed.

<span class="mw-page-title-main">Atopy</span> Predisposition towards allergy

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<span class="mw-page-title-main">Rhinorrhea</span> Filling of the nasal cavity with fluid mucus

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<span class="mw-page-title-main">Dermatophytosis</span> Fungal infection of the skin

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<span class="mw-page-title-main">Onychomycosis</span> Medical condition

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Occupational lung diseases comprise a broad group of diseases, including occupational asthma, industrial bronchitis, chronic obstructive pulmonary disease (COPD), bronchiolitis obliterans, inhalation injury, interstitial lung diseases, infections, lung cancer and mesothelioma. These can be caused directly or due to immunological response to an exposure to a variety of dusts, chemicals, proteins or organisms. Occupational cases of interstitial lung disease may be misdiagnosed as COPD, idiopathic pulmonary fibrosis, or a myriad of other diseases; leading to a delay in identification of the causative agent.

<span class="mw-page-title-main">Allergic inflammation</span>

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<i>Trichophyton rubrum</i> Species of fungus

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<i>Trichophyton</i> Genus of Fungi

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