Ringworm is caused by?

KPSC Staff Nurse - 2016

Applied Microbiology & Infection control

Easy

Appeared in: KPSC Staff Nurse - 2016

Explanation

Ringworm is a common skin infection caused by a fungus, not a worm, despite its name.
The medical term for ringworm is Tinea, and the group of fungi responsible are called dermatophytes.
These fungi thrive on keratin, a protein found in skin, hair, and nails, leading to the characteristic ring-shaped rash.
Genera of fungi that cause ringworm include Trichophyton, Microsporum, and Epidermophyton.

Option A: Protozoa are single-celled parasitic organisms. They cause diseases like malaria, amoebiasis, and giardiasis, which have different modes of transmission and clinical presentations.
Option B: This is a common misconception due to the name 'ringworm'. Roundworms are multicellular parasitic helminths that typically cause intestinal infections (e.g., Ascariasis).
Option C: Bacteria are prokaryotic microorganisms that cause a different set of skin infections, such as impetigo (caused by Staphylococcus or Streptococcus) or cellulitis. These are treated with antibiotics, not antifungals.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Ringworm (Tinea) as background academic context rather than a clinical decision trigger.
A key nursing role is patient education to dispel the myth that a worm causes ringworm. This ensures patient understanding and adherence to antifungal treatment.
Nurses must teach proper hygiene and preventive measures, such as keeping skin clean and dry and avoiding sharing personal items, to control the spread of this contagious fungal infection.
What if? If a patient with suspected ringworm does not respond to topical antifungal treatment, the nurse should consider that the diagnosis might be incorrect (e.g., it could be nummular eczema or psoriasis) or that the infection requires systemic (oral) antifungal therapy, and advise the patient to seek further medical evaluation.

How to Approach the Question

First, identify the core of the question, which is asking for the causative agent of 'ringworm'.
Recognize that 'ringworm' is a common name and might be misleading. Recall or deduce that despite the name, it is not caused by a worm.
This immediately makes 'Roundworm' a highly suspicious but likely incorrect option (a classic distractor).
Evaluate the remaining options: Protozoa, Bacteria, and Fungus. These are major classes of pathogenic microorganisms.
Recall that ringworm is a very common superficial skin infection, often presenting as a scaly, itchy patch. This clinical picture is characteristic of a fungal infection (mycosis).
Therefore, conclude that 'Fungus' is the correct causative agent.

Concept Tested & Keywords

Q0Ch0hrgsEFrYKhi3zCCLy

E6 Microbiology Essentials Sastry 4e Part 2 p. 117-119

E6 Medicine Davidson Principles Practice 24e p. 1260-1262

E6 Microbiology Applied AnjuDhir 3e Part 2 p. 68-70