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Nail Infection


Your nails can be affected by trauma, irritation, or certain infections. These conditions can involve your fingernails as well your toenails. Nail infections can be caused either by bacteria or a fungus. Paronychia is a condition of the nails which develops when bacteria enter damaged skin near the cuticle and nail fold, causing an infection. It is usually treated with antibiotics to kill the infection, but sometimes drainage of pus is required if any collection occurs. When the nails are infected with fungus, it is called onychomycosis. It can make your nails look yellow, hard, and crumble. It can be mild, non-bothering, and may not need medicine. Some may need to be treated, but it can return. 


Paronychia is usually caused by Staphylococcus aureus bacteria. Other bacteria like Streptococcus pyogenes can also cause nail infections. Bacteria penetrate the skin through cuts, broken or damaged skin, or hangnails. Certain medications can be the cause of paronychia as well. They include retinoids (used for skin treatments), HIV medications, cancer treatment medications, and specific antibiotics.

Several fungal organisms can cause Onymychosis. The most common type of fungus involved is dermatophyte. Others include yeast and molds. Dry nail cracks, reduced blood circulation, warm moist areas are predisposing factors for fungal infections.

Risk Factors

Some common risk factors include:

  • Exposure to irritants: Some detergents and chemicals can irritate the skin and result in a nail bed infection. People exposed to chemicals and those who don’t put on protective gloves during work have a higher risk.
  • Old age: Nails get dry and brittle in old age resulting in cracks. The blood circulation to the nails is also compromised as well as the immunity.
  • Biting nails or cuticles: Nail biting or picking cuticles can build tiny cracks in the nails or injure the skin. Bacteria or fungi can invade the skin through these small abrasions causing infections.
  • Prolonged feet exposure to wet: Athletes are more prone to fungal infections due to sweating. Similarly, using public shower rooms, gyms, etc., also increases risk.
  • Skin conditions: People with underlying skin problems are more likely to develop these infections. 
  • Working with water: Bartenders and dishwashing jobs that keep hands in water most of the time have a higher risk of developing nail infections.
  • Diabetes Mellitus: Having diabetes mellitus or any condition with low immunity can also increase the chances of acquiring nail infections. 


Paronychia is more common in females than males because of prolonged water use during washing dishes or clothes. Onychomycosis is more common in males and affects around 10% of the general population, of which 20% of the people are older than 60 years. 

Signs And Symptoms

Paronychia signs symptoms include: 

  • Pain
  • Swelling
  • Tenderness around the nail
  • Redness of skin
  • Warm to the touch.
  • White to yellow, pus-filled abscess may form under the skin. If any abscess formation occurs, it may require antibiotic treatment or drainage.

Onychomycosis signs and symptoms include;

·         Thickening of the nails

·         Yellowish or brown discoloration

·         Ragging or crumbling of the nails

·         Nails might smell bad


Taking history and general physical examination help in diagnosis as other tests or investigations are not required for acute mild cases. Sometimes, a tissue sample like nail clippings or debris under nails is required and sent to a laboratory to test for particular infections like bacteria or fungi. If the infection is severe and aggressively growing, imaging such as an X-ray may be required to check for the involvement of the bone tissue.

Differential Diagnosis

Several nail conditions can look like infections that may need to be excluded for efficient management.

·         Irritant Contact Dermatitis

·         Nail Psoriasis

·         Lichen Planus

·         Traumatic onycholysis

·         Drug reaction

·         Thyroid disease

·         Yellow nail syndrome

·         Melanonychia

·         Cutaneous Melanoma


If your symptoms are bothersome, you must consider consulting your healthcare provider for treatment. Nail infections caused by bacteria are treated with warm soaks and topical antibiotics, including Amoxicillin/clavulanate or fluoroquinolones. Topical steroids may or may not be required. Fungal nail infections may sometimes be difficult to treat. Treatment depends on the severity and the type of fungus responsible for the infection. It may take a prolonged time to treat the condition. If the nail condition improves, then recurrent infections are also common, which must be seen.

Medications: Some therapies for treating fungal infections include:

·         Oral antifungal medicines: These drugs are frequently the first choice because they clear the infection more abruptly than topical drugs. Some of them are terbinafine (Lamisil) and itraconazole (Sporanox) taken for 6 to 12 weeks.These drugs help grow new nails free of infection, slowly replacing the part of the infected nail. But the results of treatment will be evident after the nail grows entirely. It may take more than four months to cut off infection. The success of treatment with these drugs is lower in the elderly, over the age of 65 years.

  • Medicated nail polish: An antifungal nail polish called ciclopirox (Penlac) may be prescribed daily for infected nails and surrounding skin. It can be wiped out after seven days, the piled-on layers are cleaned with alcohol, and new applications are made. One-year treatment may be required.
  • Medicated nail cream: An antifungal cream is prescribed in topical treatment, which is rubbed in the infected nail after soaking it for some time. These treatments may work effectively if first the nails are trimmed and filed. This helps in better penetration of the medication as hard nail surface is a barrier for effective penetration to the underlying fungus.

Surgery: In cases of abscess formation, you may need incision and drainage. For chronic fungal infections, surgeons might suggest temporary removal of the nail so that they can apply the antifungal drug directly into the infected area under the nail. Some fungal nail infections are resistant to medications, so the doctor might suggest permanent nail excision if the infection is spreading, severe, or intensively painful.


Paronychia is easily cured with treatment. Some may get multiple infections or recurrent infections (chronic paronychia). The untreated infections can extensively damage the nail. Some untreated paronychia can spread deeper into the finger or toe's deep tissues and bones, resulting in a serious infection. People with diabetes or people with underlying medical issues get chronic paronychia. If proper care and medication regimen are taken, fungal infections can be cured. Otherwise, there are more chances of resistance or relapse of the infection. 


To prevent a nail infection, certain measures are useful

  • Avoid biting, chewing, picking nails or cuticles. 
  • Don't cut the nails too short.
  • Ensure good hygiene by keeping hands clean and keeping nails cut and clean.
  • Change your socks regularly and use breathable shoes.
  • Consuming gentle soaps that don’t irritate the skin.
  • Use emollients on the nail fold and cuticles if the skin is dry. Excessive dryness can cause the cracking of the skin. 
  • Use gloves while working with chemicals.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 04, 2023.




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