The ringworm myth

Contrary to its name, ringworm is a superficial skin infection caused by a fungus, not a “worm”.

It is a disease recognised since the early 1800s. The infection manifests as a circular red rash with a central clearing resembling a ring. Anyone (including healthy individuals) can get ringworm.

Medical professionals refer to ringworm as “tinea” or “dermatophytosis.” Ringworm infections can also sometimes be named based on their location on the body – for instance, foot ringworm is also known as “athlete’s foot”, while ringworm affecting the groin and inner thigh can be called “jock itch”.

Despite the abundance of hair that helps to protect or shield our scalp, the human scalp is not spared from infection. Scalp ringworm was once dubbed “scald head” in the early 19th century.

In addition to the discernible reddish ring-like lesion on the skin, a ringworm infection can cause the skin to become scaly and itchy. Expect hair loss or bald patches if the scalp is affected.

Several fungal genera collectively known as dermatophytes have been implicated as causative agents of ringworm, of which Trichophyton and Microsporum are among the most notable.

In contrast to other fungal genera that infect humans (e.g., Aspergillus and Candida), dermatophytes can utilise the keratin in human skin, nails and hair as their nutrient source.

Thus, the symptoms of ringworm are attributed to allergic and inflammatory responses elicited by the host in response to the presence of the dermatophyte (and its metabolic products) on the skin.

Among the risk factors for ringworm are using public showers or pools barefooted, playing contact sports such as rugby or wrestling, and sharing items intended for personal use such as footwear, combs or towels.

Wearing damp or sweaty garments such as socks and underwear can also predispose a person to ringworm because fungi thrive in high-moisture environments.

It is imperative to note that humans are not the sole reservoirs for dermatophytes. You can contract ringworm via close contact with domesticated farm animals (e.g., cattle and horses), household pets (e.g., cats and dogs), and even soil.

It is advisable to wash hands with soap and running water after physical contact with such animals or soil.

While the infection can be diagnosed clinically by general practitioners and dermatologists, a definite diagnosis can only be achieved through the culture of skin scrapings or epilated hairs in a microbiology laboratory.

Dermatologists frequently employ Topical corticosteroids (in the form of creams or ointments) to manage a variety of skin rashes.

Some, such as discoid eczema, pityriasis rosea, psoriasis, and contact dermatitis, can also present themselves with ring-like skin lesions.

Therefore, some individuals may unwittingly self-treat a skin rash with a potent steroid preparation without realising it is actually ringworm.

Any respite in redness and itch by steroid therapy does not indicate that the ‘ringworm’ has been treated.

On the contrary, because of the steroid-induced suppression or weakening of the skin’s natural defences, the fungus can propagate and involve more body areas or even invade deeper into the skin.

A steroid-treated ringworm lesion can also have an atypical appearance, making it challenging for medical professionals to diagnose and manage.

The cornerstone of ringworm management is an antifungal agent (eg. terbinafine, clotrimazole or miconazole) prescribed for two to three weeks.

The extent of the infection would dictate whether the agent is administered orally or topically.

Although preparations combining a mild steroid (typically hydrocortisone) with an antifungal agent exist and is available over the counter in Malaysia, the general public should refrain from using them unless sanctioned by a medical professional. The Health 

Associate Professor Dr Tan Toh Leong is an emergency medicine physician and medical lecturer with the Department of Emergency Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia (UKM). He is also the founder and president of Malaysian Sepsis Alliance (MySepsis).

Associate Professor Dr Ding Chuan Hun is a clinical microbiologist and medical lecturer with the Department of Medical Microbiology & Immunology, Faculty of Medicine, UKM, and a member of MySepsis.