FUNGAL INFECTIONS
Chronic fungal infections are common in the elderly; the age-related decrease in cutaneous immunologic response may be partly responsible.
Tinea Pedis
(Athlete’s Foot) Tinea pedis is discussed in Ch. 77.
Tinea Unguium
A fungal infection of the nails (more often the toenails than the fingernails), usually caused by Trichophyton rubrum or T. menta-grophytes. The nails may become grossly thickened and so enlarged that wearing shoes becomes painful.
Treatment: Treatment is prolonged and rarely warranted. Fingernails may be treated with griseofulvin 500 to 1000 mg/day for 6 to 9 mo; toenails require 12 to 18 mo of such therapy. The overall cure rate is 40% to 70%. Although fingernails are more likely to respond to treatment than toenails, recurrence within 1 yr is common; recurrence in toenails is nearly 100%. Available topical antifungals are fungistatic and do not penetrate the nail plate in sufficient concentration to eradicate infection. Fungicidal agents now under investigation offer the prospect of effective topical therapy for tinea unguium. In elderly patients whose main problem is discomfort, conservative management including periodic trimming by a podiatrist may be the most practical approach.
Tinea Cruris
A cutaneous fungal infection of the groin that commonly affects the elderly. Predisposing factors include clothing made of synthetic fabrics that do not breathe, obesity, and immobility.
The patient usually complains of itching, and examination may reveal scaly erythematous areas with well-defined margins. Maceration, lichenification, and secondary candidal or bacterial infection are common. Diagnosis requires microscopic examination of a specimen prepared with potassium hydroxide (KOH) solution.
Treatment: Miconazole 2% or clotrimazole 1% cream should be used bid or tid. Affected areas should be kept as clean and as dry as possible, using cotton between the toes and talc-based powders.
Tinea Incognito
(Steroid-Modified Tinea)
A fungal infection in which clinical manifestations are modified by topical or systemic corticosteroids. When treated with topical corticosteroids, fungal infections appear to improve: inflammation subsides and scaling decreases. But attempts to discontinue the agent result in flare-ups. Prolonged use of corticosteroids can cause striae, atrophy, and telangiectasia to develop with the original dermatitis. Specimens prepared with KOH solution are floridly positive.
Treatment: A topical antifungal agent should be used. If a potent topical corticosteroid has been used, the number of applications may need to be gradually reduced to minimize the rebound flushing and fixed vasodilation seen in steroid-dependent skin.