What is the Difference Between Onychomycosis and Paronychia

The key difference between onychomycosis and paronychia is that onchomycosis is a fungal infection of the toenails or the fingernails due to fungi such as dermatophytes, yeasts, and nondermatophyte mold while paronychia is an infection of the proximal and lateral toenail and fingernail folds due to bacteria such as Staphylococcus aureus or Streptococcus pyogenes.

Nail diseases are dermatological diseases that can affect the health, strength, and appearance of fingernails and toenails. These infections may include nail psoriasis, onychoschizia, onychogryphosis, ingrown toenails, nail fungal and bacterial infections, onycholysis, etc. Onychomycosis and paronychia are two dermatological disorders of the nail. Both these disorders can affect toenails and fingernails. However, they have different aetiologies. Therefore, the treatment regimens for both these disorders would be different.

CONTENTS

1. Overview and Key Difference
2. What is Onychomycosis  
3. What is Paronychia
4. Similarities – Onychomycosis and Paronychia
5. Onychomycosis vs Paronychia in Tabular Form
6. Summary – Onychomycosis vs Paronychia

What is Onychomycosis?

Onychomycosis is a fungal infection of the nail plate, nail bed, or both. It affects toenails or fingernails and is caused by fungi such as dermatophytes, yeasts, and non-dermatophyte mold. After an infection, nails would be deformed and decoloured to appear white or yellow. The risk factors for onychomycosis may include tinea pedis, previous nail dystrophy, older age, male sex, exposure to someone with tinea pedis or onychomycosis, peripheral vascular disease or diabetes, and compromised immune function.

The signs and symptoms of onychomycosis can manifest as infected nails displaying an abnormal appearance that isn’t accompanied by itchiness or pain. Affected nails might exhibit patches of white or yellow discoloration, as well as a chalky white scale that gradually spreads beneath the nail’s surface. The nails can become thickened, deformed, and discolored, and there’s a possibility of nail detachment from the nail bed. Additionally, debris from the infected nail might accumulate under its free edge.

Onychomycosis can be diagnosed through the appearance of the nails, examine a sample of the nail debris under a microscope, and polymerase chain reaction (PCR). Furthermore, treatment options for onychomycosis may include oral antifungal drugs such as terbinafine, fluconazole, or itraconazole and topical antifungal drugs such as efinaconazole and tavaborole.

What is Paronychia?

Paronychia is a nail infection caused by bacteria. It affects proximal and lateral toenails and fingernail folds. Moreover, paronychia symptoms include pain, swelling, and tenderness around the nail, skin that turns red color and warm to touch, pus building under the skin, nails that may look yellow or green, dry and brittle, and nails that detach from the nail bed and fall off. The risk factors for paronychia may include cuts, broken skin or hanging nails, ingrown nails, irritation from water or chemicals, trauma to the nailbed or cuticle area, and medications such as retinoids, anti-cancer medications, HIV medications, and some antibiotics.

Paronychia can be diagnosed through physical examination, observing a sample of the tissue under a microscope, and imaging tests such as X-rays. Furthermore, paronychia can be treated through antibiotics such as dicloxacillin, cephalexin, trimethoprim-sulfamethoxazole, doxycycline, and amoxicillin.

What are the Similarities Between Onychomycosis and Paronychia?

• Onychomycosis and paronychia are two dermatological disorders of nails.
• Both these disorders can affect toenails and fingernails.
• Both these disorders may have similar symptoms, such as nail discoloration, nail that detaches from the nail bed and falls off, etc.
• Both these disorders can be diagnosed through physical examination and observing tissue samples under the microscope.
• They can be treated through specific medications.

What is the Difference Between Onychomycosis and Paronychia?

Onychomycosis is a fungal infection of the toenails or the fingernails due to fungi such as dermatophytes, yeasts, and non-dermatophyte mold, while paronychia is an infection of the proximal and lateral toenail and fingernail folds due to bacteria such as Staphylococcus aureus or Streptococcus pyogenes. Thus, this is the key difference between onychomycosis and paronychia. Furthermore, the risk factors for onychomycosis may include tinea pedis, previous nail dystrophy, older age, male sex, exposure to someone with tinea pedis or onychomycosis, peripheral vascular disease or diabetes, and being immunocompromised. On the other hand, risk factors for paronychia may include cuts, broken skin or hanging nails, ingrown nails, irritation from water or chemicals, trauma to the nailbed or cuticle area, and some medications such as retinoids, anti-cancer medications, HIV medications, and some antibiotics.

The infographic below presents the differences between onychomycosis and paronychia in tabular form for side-by-side comparison.

Summary – Onychomycosis vs Paronychia

Onychomycosis and paronychia are two dermatological disorders of the nail. Onychomycosis is a fungal infection of the toenails or the fingernails due to fungi such as dermatophytes, yeasts, and non-dermatophyte mold. Paronychia is an infection of the proximal and lateral toenail and fingernail folds due to bacteria such as Staphylococcus aureus or Streptococcus pyogenes. So, this summarizes the difference between onychomycosis and paronychia.

Reference:

1. Antonella Tosti, MD. “Onychomycosis: Practice Essentials, Background, Pathophysiology.” E-Medicine – Medscape.
2. “Paronychia.” DermNet.

Image Courtesy:

1. “Oncymycosis” By James Heilman, MD – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Paronychia green discolor” By X-Fi6 – Own work (CC0) via Commons Wikimedia