Dr. Kiran Godse, a noted Dermatologist, and Dr. Dakshata Tare, a senior Dermatologist, help us understand the common fungal infections seen in Diabetes Mellitus patients and share their expertise in managing such conditions in this two-part series.

Diabetes mellitus (DM) is a metabolic disorder prevalent in all socio-economic strata of the society. The total number of diabetics in India was estimated to be around 40.9 million in 2000 and this is further set to rise to 60.9 million by 2025, according to The International Diabetes Federation. In India, a superficial dermatophytosis epidemic is underway with an alarming increase seen in its the incidence and prevalence. In DM, uncontrolled hyperglycemia leads to impaired cellular immunity and reduced phagocytic function of polymorphonuclear leukocytes which predispose individuals to fungal and bacterial infections.

 Approximately 79.2% of diabetics suffer from various dermatoses of which fungal infections form a significant part. 

Oral candidiasis, vulvovaginal candidiasis, candidial balanoposthitis and onychomycosis are frequently observed in diabetics. Tinea pedis and onychomycosis are the most common infections seen in diabetics in various studies. 

How to identify the presenting fungal infection

Cutaneous Candidiasis: Mucocutaneous candidiasis is commonly associated with DM as hyperglycemia favours candidal proliferation. It chiefly presents as vulvovaginal candidiasis, candidal balanoposthitis, perianal candidiasis, oral thrush, perleche, intertrigo, finger web space infection, paronychia and onychomycosis. Yeast infections may be the only and first presentation of DM.

• Candidal balanitis: It presents as erythematous red patches on the glans penis along with fissures and cracks on the prepuce associated with itching and soreness. Phimosis is a frequent association in diabetic males with recurrent or chronic candidal balanoposthitis. Older males with recurrent phimosis secondary to balanitis should be investigated for DM.
• Oral thrush: DM is an important risk factor for oral candidiasis. The symptoms include a burning mouth, altered taste, intolerance to spicy food. Involvement of the oropharynx presents with dysphagia and odynophagia. It is characterised by curdy white patches covered with pseudomembrane over the gums, gingiva, tongue, palate. On removal, the membrane reveals erythematous base.
• Vulvovaginal candidiasis: Pruritus vulvae is a common association with DM characterised by vulval erythema, with fissuring, vulval itching, soreness, pain, dyspareunia and thick curdy white discharge.
• Candidal paronychia: Infection of the nails is common in DM. Clinically, it presents as erythema, swelling, with lateral nail fold separation along with separation of the cuticle from the nail. It is associated with dystrophy of the nail, transverse indentations, striations.

Dermatophytosis: It is a superficial fungal infection of keratinised tissue namely skin, hair and nail. The clinical presentation of the disease depends on the site, organism and host factors. A study on clinical profile and socio-demographic factors revealed a significant association between DM and duration of disease. The alteration in hosts immune response to the fungus in diabetic patients is responsible for the increased susceptibility and chronicity of infection Factors such as peripheral vascular disease, peripheral neuropathy, elevated blood sugar levels and impaired immune response increase the susceptibility to fungal infections of the feet and nails

According to a study conducted in 2016, distal subungual onychomycosis followed by tinea pedis were more frequent fungal infections observed in DM.

Tinea pedis: - It may present as one of the following variants:

• The chronic intertriginous type: It is the most common type characterised by maceration, scaling and fissuring in the interdigital and sub-digital areas.
• The chronic papulosquamous type: It is characterised by diffuse or patchy moccasin-like scaling over the soles and sides of the feet.
• The vesicular or vesiculobullous type: Small vesicles or vesiculo-pustules are seen on the instep and the mid-anterior plantar aspect along with associated scaling in these areas and the toe-webs.
• The acute ulcerative variant: It is associated with maceration, weeping, denudation and ulceration on the soles. This variant commonly gets complicated by secondary bacterial infection.

Tinea corporis: The classical lesion is annular or polycyclic plaques with erythematous and scaly or vesicular borders and central clearing. Concentric rings may be seen. As diabetics tend to develop chronic infection, the lesions may extensive with severe scaling and lichenification.

Tinea cruris: It is characterised by erythematous plaques with active borders and central clearing in the genitocrural area and on the medial aspect of the upper thigh. They may coalesce and extend to the lower abdomen, lower back and buttocks.

Tinea unguium and onychomycosis:  Onychomycosis is a common dermatophytic infection seen in diabetics. The distal and lateral subungual onychomycosis (DLSO) is the most common subtype seen in DM. Toenails are commonly involved than fingernails.

Tinea pedis is a frequent association with onychomycosis as the nail serves as a reservoir of infection. It makes the nail thick, yellow and brittle. Though it is unlikely to be associated with any complications in non-diabetics, however, in diabetics the infection can cause secondary bacterial infection, cellulitis, osteomyelitis, gangrene and rarely lower limb amputation. (10-14) Tinea pedis may cause foot ulcerations due to the development of fissures in the affected area. Onychomycosis can also lead to foot ulceration due to the pricking injury caused by the thick, sharp, brittle piece of nail piercing the skin along with the vascular compromise caused by subungual pressure of the thickened nail.

Read about the management of these conditions in the next part, Managing fungal infections in Diabetes: Dr. Kiran Godse & Dr. Tare.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.