Fungal infections of the skin can be divided into those associated with yeasts such as Candida albicans and others caused by dermatophytes or ringworm fungi.
Use of drugs such as corticosteroids, cytotoxics, antibiotics and oral contraceptives can predispose to candidiasis. It is now a major problem in patients with AIDS.
Local factors in the skin, such as maceration, may predispose to secondary invasion at sites such as the groin or breast fold, particularly if obesity is present.
Maceration of the skin in body folds, especially in the obese, induces erosion and intertrigo (Fig. 20.9). In a similar fashion, the wet napkins of infants may encourage opportunistic infection with C. albicans.
Candidiasis is a common cause of a vaginal discharge and leads to pruritus vulvae. It can be a presenting feature of diabetes mellitus. Other causes are:
• Vaginal discharge due to Trichomonas, bacterial vaginosis or other causes
• Scabies and pediculosis
• Contact dermatitis
• Senile atrophy
• Lichen sclerosus et atrophicus
Aggravating factors include poor hygiene, obesity, tight clothing and excess washing with soap. Treatment depends on the cause
Chronic maceration of the skin is important in the development of paronychial infection. Commonly the seal or eponychium at the proximal nail fold is lost by continual immersion of the hands in water or by manicure. A space is opened up beneath the nail fold and the continuing moist environment suits the growth of C. albicans. Disease is manifest by a swelling or bolstering of the nail fold, erythema, pain and deformity of the nail plate.
Greenish black discoloration of the nail plate often indicates concomitant infection with organisms such as Ps. aeruginosa, which thrives in the same moist environment.
An attempt to dry areas of contiguous skin, e.g. beneath the breasts by interposing an absorbent material between the two skin surfaces, is important. The routine use of a fine powder containing antifungal agents such as miconazole or clotrimazole as a talc after washing is helpful. Specific antifungal agents used are nystatin, which has only topical activity, and an imidazole (e.g. clotrimazole
or miconazole) cream, lotion, spray or powder . Fluconazole and itraconazole are new oral triazoles and are used particularly for vaginal candidiasis.
In severe intertrigo it is important to incorporate a low-potency steroid together with the antifungal agent in order to allay the inflammatory changes, itching and excoriation.
More serious and widespread disease in infants or those who are immunocompromised by disease or therapy may be effectively treated with oral ketoconazole 200- 400 mg daily. The unusual but potentially serious hepatotoxic effects of this drug require that it should be reserved for very intractable or life-threatening disease.