Frans Radebe, NICD/NHLS
A 36 years male presented in Alexandra Primary Health Care clinic with elevated red inflamed lesions on both the groins.
The lesions had a distinct border and spread around the pubic area with some patches on the penis but no lesions on the scrotum. The edge of the rash was very distinct and scaly with bumps-like blisters. There were no lesions on the folds of the buttocks. The lesions appeared to develop into deeper skin infection. He complained of itchiness that needed occasional scratching. No laboratory tests were performed as the condition was deemed not a sexually transmitted infection.
Question 1: What is the likely cause and what factors predispose to this infection?
Answer to Q1
The rash is caused by Tinea cruris.
The exact incidence of Tinea cruris is difficult to determine but its prevalence is common. It is not a notifiable disease and patients are able to recognise and treat it until it is cured. In terms of its epidemiology, it is less common in some groups but common in older male patients and prepubertal children. Climates where humidity is high and temperatures are higher exhibit increased rates of Tinea cruris. Chronic Tinea cruris in immunosuppresed individual with herpes, may be characterized by scaling, vesicles or pustules, excoriations and erosion in the folds of the groin. Also, people with immunocompromise, i.e. diabetes, chemotherapy, HIV or hepatitis are very vulnerable.
The main symptoms are scaly red rash spreading down from groin to upper thighs, buttocks and perineum. It does not usually involve penis or scrotum. It causes itching or a burning sensation in the groin area, thigh skin folds or anus. It may involve the inner thighs and genital areas, as well as extending back to the perineum and peri-anal areas. Affected areas may appear red, tan or brown with flaking, peeling or cracking skin which may exhibit tiny pimples or pustules. If infected with candidal organisms, the rash tends to be redder and wetter and have a stronger, yeast-like smell. The skin of the penis may be involved, whereas other organisms spare the penis
Poor blood circulation and low blood oxygen can also contribute to the fungus growth. Tinea cruris is not often considered to be a sexually transmitted disease, but skin-to-skin genital contact could lead to inoculation in the partner’s groin. While the condition is not as common in females, it can occur due to sexual transfer, and simultaneous treatment for the male partner should also be recommended to prevent reinoculation. In addition, sharing towels, clothing, swimsuits or not washing your hands after contact with the infected area will spread this fungus. If one goes to the public pool or gym often, it is better to get a shower before and after visiting.
Question 2: What is the differential diagnosis and what other investigations would you do to confirm the diagnosis?
Answer to Q2
When considering symptoms of Tinea cruris, it is also important to consider:
A Potassium hydroxide (KOH) test can be done to confirm the presence of Tinea cruris which involves the gentle scrapping of the top of the lesion and examining the flakes of the skin under a microscope, thus excluding the first three differential diagnoses.
Under the microscope, the fungus looks like translucent, branching, rod-shaped filaments or hyphae.
A Wood’s lamp to examine the affected areas is useful to consider the other differential diagnosis for other conditions is to shine a Wood’s lamp light onto the area involved and the lesions will glow coral red.
Question 3: How would you treat the case
Answer to Q3
Non-prescription treatment is relatively simple and provides a complete cure when products are used as directed. If the rash doesn’t improve with topical therapy, systemic medication may be required.
The patient returned two weeks after the initiation of antifungal treatment, the lesions had subsided and was encouraged to complete the treatment even though the lesions seemed better. He was given health education in terms of personal hygiene which included the prevention of further infection, which may be related to auto-inoculation.
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