Tinea Ungium (Onychomycosis)

CLINICAL 

FEATURES

INTRODUCTION

Nail Anatomy

Onychomycosis

• Nail disorders can arise at any age.

• Assessed by:
• Clinical inspection
• KOH/Culture
• Histopathology

• About half of all nail disorders are of infectious origin

• Defined as fungal infection of the nail, represents up to 15%-20% of all nail disorders.

• Onychomycosis can be due to:
• Dermatophytes such as Trichophyton rubrum (T rubrum), T. interdigitale. The infection is also known as tinea unguium.
• Yeasts such as Candida albicans.
• Moulds especially Scopulariopsis brevicaulis and Fusarium species.

EPIDEMIOLOGY

Tinea Ungium

• Tinea ungium refers specifically to dermatophyte infection of the nail organ.

• Infected nails are opaque, friable, yellow and thickened.

• One or all nails (of hands and feet) may be infected.

• Trichophyton Rubrum and Trichophyton Mentagrophytes are the most common pathogens responsible for most cases of tinea ungium.

• Prevalence of Tinea Ungium and Onychomycosis is assessed in several studies.

• A study by Sofia P et al evaluated the prevalence of Tinea Ungium in 1,000 healthy individuals in Madrid, Spain:
• the prevalence of tinea unguium in the population studied was 2.8%.

• Other studies indicate the prevalence of onychomycosis approximately 6.5% in Canada and 14% in North America.

PATHOPHYSIOLOGY

CLASSIFICATION

Surgical Therapies

• Mechanical debridement
• Surgical Nail Avultion

Oral Anti Fungal Therapy

Terbinafine: (250 mg/d. 6–8 w for fingernail 12 w for toenail)

Itraconazole: 200mg/d. 6 weeks for fingernails & 12 weeks for toe infection.

(Pulse: 400mg/d. 1w/m. 2-3m.)

Fluconazole: 150-300mg/w. 3-6w

Griseofulvin: 0.5-1 g/d. 6-12m

Topical Antifungals

Progression of Fungal Infection

• Should be used in combination with systemic anti-fungal therapy.
• Amorolfine (Loceryl 5%)
• Ciclopirox
• Terbinafine

• Fungal organisms invade nail (between the nail plate and nail bed) through an opening in the sub-ungual space of the hyponychium, near the distal groove. The infection starts distally, then progresses proximally.

INTRODUCTION

Emerging Therapies

Device Based Approaches

• Iontophoresis: electric current
• Ultrasound: canine hoof model

Combination Therapy

Biophysical Therapies

• Laser: Nd Yag, Q switch
• Photodynamic: Singlet O2

(interection light+photosentizer)

• The types of microorganisms that cause onychomycosis can be broadly classified into 2 groups:

• Dermatophytes are fungi that infect keratinous tissue.
• Non-dermatophytes that can cause onychomycosis are either yeasts or molds.

• Nail unit consists of proximal and lateral folds, cuticle, matrix, plate, bed, and hyponychium.

• Cuticle consists of modified stratum corneum protects the matrix from exposure to infection.
• The matrix is the growth center of the nail.
• The nail plate is attached to the top of the nail bed.
• The nail bed is located under the nail plate and consists of epidermal grooves and ridges that contain small blood vessels.

• The location where the nail plate distally detaches from the nail bed is called the hyponychium, which extends from the nail bed to the distal groove.

TREATMENT

CONCLUSION

EPIDEMIOLOGY

Topic Review

TINEA UNGIUM

(ONYCHOMYCOSIS)

Dr. MUHAMMAD AWAIS ARIF

PATHO-PHYSIOLOGY

TREATMENT

Diagnosing Onychomycosis

Clinical diagnosis is quite accurate.

Confirmatory tests:

1. KOH wet mount

2. Fungal culture (type identification)

2. Nail Histopathology

Types of Onychomycosis

Onychomycosis has six subtypes:

1. Distal and Lateral Subungual Onychomycosis

2. White Superficial Onychomycosis

3. Proximal Subungual Onychomycosis

4. Endonyx Onychomycosis

5. Candidal Onychomycosis

6.  Total Dystrophic Onychomycosis

1. Distal and lateral subungual onychomycosis (DLSO)

6. Total Dystrophic Onychomycosis

• Fungi reach the nail through the hyponychium.
• The nail plate appears yellow-white, and detached.
• DLSO May be associated with black pigmentation

     “fungal melanonychia”

Most severe stage of onychomycosis, and it can result from a long-standing DLSO or PSO

DLSO, whitish discoloration, onycholysis and subungual hyperkeratosis

DLSO with yellow discoloration

Pigmented DLSO

Total dystrophic onychomycosis: the nail plate is completely invaded by fungi and friable.

KOH mount showing branching septate hyphae

4. Endonyx Onychomycosis

2. White Superficial Onychomycosis

(WSO)

Fungi invade the dorsal nail plate and form colonies that appear as white opaque formations.

• Nail plate invasion without nail bed involvement.
• Nail milky white discoloration
• Caused by T. soudanense or T. violaceum

Nails should be scraped or clipped near the bed

3. Proximal subungual onychomycosis (PSO)

5. Candidal Onychomycosis

Fungus is typically located in the ventral nail plate, producing a proximal leukonychia

WSO: White opaque friable patches of nail plate due to Trichophyton interdigitale

Tinea Pedis interdigitalis, often associated with WSO

Occurs in patients with chronic mucocutaneous candiasis and are caused by C. Albicans

1. Candida Paronychia

2. Candida Granuloma

3. Candida Onycholysis

Endonyx onychomycosis: white discoloration of the nail plate that is firmly attached to the nail bed.

PSO, White discoloration of proximal nail plate.

Candidal Onychomycosis

PAS stain reveals dermatophytes penetrating the nail plate

DIAGNOSIS

CLINICAL

FEATURES

DIFFERENTIAL

DIAGNOSIS

Proximal Subungual Onychomycosis (PSO):

Distal and Lateral subungual onchychomycosis (DLSO):

• Acute bacterial Paronychia.

• Pustular Psoriasis of the nail.

• Traumatic onycholysis (usually symmetrical, no subungual hyperkeratosis)

• Nail psoriasis (diffuse hyperkeratosis, several/all toenail involved, others skin and nail signs of psoriasis)

Other Differentials:

White Superficial Onychomycosis (WSO)

• Lichen Planus
• Irritant Contact Dermatitis
• Chronic Paronychia
• Paronychia Congenita
• Bacterial Infections
• Yellow nail syndrome
• Twenty nail dystrophy (Trachyonychia)

• Superficial nail fragility due to prolonged wearing of nail polish.

• Transverse toe nail leukonychia due to trauma.