Q. A patient presents with itchy vesicles and scaling on the feet, as shown in the image. What is the most likely diagnosis?
Options:
A) Dyshidrotic eczema.
B) Scabies.
C) Contact dermatitis.
D) Tinea pedis.
Correct Answer: D) Tinea pedis.
High-Yield Review
Tinea pedis, commonly called athlete’s foot, is a superficial fungal infection of the feet caused by dermatophytes.
It is particularly common in warm, humid environments and in people whose feet remain sweaty or enclosed in footwear for prolonged periods.
The infection can produce itching, scaling, fissuring, and sometimes small vesicles, depending on the clinical subtype.
The vesiculobullous form typically produces itchy, fluid-filled vesicles, often involving the medial or plantar surface of the feet.
Clinical Features
Tinea pedis can appear in several patterns-:
1. Interdigital type: Scaling, maceration, and fissuring, especially between the toes.
2. Moccasin type: Dry, diffuse scaling over the soles and lateral borders of the feet.
3. Vesiculobullous type: Itchy vesicles or small blisters, usually on the plantar or medial foot.
4. Ulcerative type: More severe infection with erosions and ulceration, particularly in susceptible individuals.
A useful clinical clue is itchy scaling of the feet, especially between the toes or along the soles.
Diagnosis
Tinea pedis is often diagnosed clinically. When confirmation is needed, skin scrapings examined with potassium hydroxide (KOH) preparation can demonstrate fungal hyphae.
KOH examination is particularly useful when the appearance is atypical or when eczema or contact dermatitis is being considered.
Treatment
Most uncomplicated cases respond well to topical antifungal therapy, such as topical azole or allylamine agents.
Keeping the feet clean and dry, changing socks regularly, and avoiding prolonged moisture helps prevent recurrence.
Extensive, recurrent, or treatment resistant infection may require systemic antifungal therapy after appropriate clinical assessment.
Tinea Pedis vs Common Differentials
1. Dyshidrotic eczema: It characteristically produces intensely itchy, small vesicles on the palms, sides of fingers, and/or soles. It is an important clinical differential for vesicular lesions on the feet.
2. Scabies: It usually causes intense generalized nocturnal itching, with typical lesions and burrows involving sites such as the finger webs, wrists, waist, and genital region.
3. Contact dermatitis: It often corresponds to an area exposed to an irritant or allergen and may have erytuhema, itching, scaling, or vesicles.
∆ High-Yield Exam Pearls:
Tinea pedis = Athlete’s foot.
Causative organisms: Dermatophytes, commonly Trichophyton species.
Vesiculobullous tinea pedis: Itchy vesicles on the plantar/medial foot.
Moccasin type: Diffuse scaling of the sole and lateral foot.
Diagnostic test: KOH preparation of skin scrapings.
Treatment of uncomplicated disease: Topical antifungal therapy.
✓ One-Liner to Remember:
“Itchy scaling between the toes or on the sole, with possible vesicles → think Tinea pedis.”
✓ Take-Home Message:
Tinea pedis (athlete’s foot) is a common dermatophyte infection characterized by itching, scaling, fissuring, and sometimes vesicles on the feet.
Recognizing its different clinical patterns and distinguishing it from dyshidrotic eczema, scabies, and contact dermatitis is important both in clinical practice and in MBBS, NEET PG, INICET, FMGE, USMLE, PLAB and other medical examinations.
