INFECTIONS
The age-related decline in immune function is reflected in a higher incidence of certain chronic skin infections, such as tinea pedis. The compromised tissue perfusion and slower healing of aging skin may explain the increased tendency toward bacterial superinfection of wounds in older persons.
BACTERIAL INFECTIONS
Impetigo
A superficial skin infection caused by staphylococci or streptococci. Vesicles or pustules in the early stages break down to form golden brown crusts that often adhere to the underlying skin. If the infection is extensive, malaise, fever, and lymphadenopathy may occur. Impetigo often develops as a secondary infection in conditions characterized by breaks in the skin that allow microbes to penetrate (eg, eczema, senile pruritus, pediculosis, nodular prurigo, and herpes zoster).
Treatment: Single or localized lesions should be soaked for 10 min in a drying agent such as Burow’s solution (aluminum acetate 5%). Extensive lesions require systemic antibiotics to reduce the risk of glomerulonephritis and prevent impetigo from spreading. A skin swab should be taken for microbial culture and sensitivity assays.
Patients with streptococcal pyoderma should be treated with penicillin V 250 to 500 mg orally qid for 10 days. If patient compliance is unlikely, long-acting penicillin G benzathine 1.2 million u. IM may be necessary. If the patient is allergic to penicillin, erythromycin 250 to 500 mg orally qid can be given. Patients with staphylococcal pyoderma should receive dicloxacillin 250 to 500 mg orally qid for 10 days.
Staphylococcal Scalded Skin Syndrome
(Ritter’ s Disease)
A severe, extensive bullous condition caused by a staphylococcal skin infection, in which the epithelium lifts off in sheets leaving large denuded areas. Although generally a disease of young children, the
condition is increasingly appearing in immunocompromised adults. In elderly patients, staphylococci usually invade the skin and the blood, and death usually results from septicemia.
Toxic epidermal necrolysis, an adverse drug reaction that can produce an identical clinical picture, must be considered in the differential diagnosis. Both these conditions are life threatening and require hospitalization. To differentiate between staphylococcal scalded skin syndrome and toxic epidermal necrolysis, the examiner observes a frozen section from a skin scraping or biopsy to determine the level of cleavage. In staphylococcal scalded skin syndrome, cleavage occurs within the epidermis just below the granular layer. In toxic epidermal necrolysis, subepidermal blister formation occurs with basal cell damage. Differentiation is important because staphylococcal scalded skin syndrome must be treated immediately with penicillinase-resistant antistaphylococcal antibiotics.
Treatment: Therapy is the same as for severe burns, beginning with immediate fluid and electrolyte replacement. A systemic antibiotic (eg, IV oxacillin) should also be given promptly. The source of infection may be difficult to isolate, but culture specimens should be taken from the skin, blood, nares, and any other suspected sites. Silver sulfadiazine cream may help prevent cutaneous superinfection with gram-negative bacteria. Even with treatment, the prognosis is poor.
Erysipelas
A superficial infection of the skin caused by group A or group C hemolytic streptococci. The organisms may enter the skin through minor cuts, wounds, or insect bites.
The affected area may be red and swollen. The lesions have well-defined margins that advance as the infection spreads. Vesicles or bullae may be present, and in the elderly, hemorrhage may occur. Fever, malaise, and lymphadenopathy may also develop.
Treatment: Penicillin V or erythromycin 250 to 500 mg orally qid should be given for 2 wk. Because the infection continues to spread during the first 12 to 24 h of oral therapy, patients with facial lesions often require hospitalization and IV antibiotics to prevent cavernous sinus thrombosis.
Cellulitis
A deep infection of the skin, most frequently caused by group A streptococci and occasionally by gram-negative organisms. In the elderly, cellulitis most commonly occurs as a complication of an open wound, such as a venous ulcer. However, it also develops in intact, edematous skin, especially in the legs. Erythema, tenderness, swelling, warmth, and lymphadenopathy may be present.
Treatment: Penicillin or erythromycin 250 to 500 mg orally qid should be given for 2 wk. If the lesion is large or near a vital structure or if the patient has fever, diabetes mellitus, or peripheral vascular disease or cannot be closely monitored, initial IV therapy is recommended. In some patients, cellulitis responds slowly to antibiotics, and prolonged treatment is needed.

The age-related decline in immune function is reflected in a higher incidence of certain chronic skin infections, such as tinea pedis. The compromised tissue perfusion and slower healing of aging skin may explain the increased tendency toward bacterial superinfection of wounds in older persons.
BACTERIAL INFECTIONS
Impetigo
A superficial skin infection caused by staphylococci or streptococci. Vesicles or pustules in the early stages break down to form golden brown crusts that often adhere to the underlying skin. If the infection is extensive, malaise, fever, and lymphadenopathy may occur. Impetigo often develops as a secondary infection in conditions characterized by breaks in the skin that allow microbes to penetrate (eg, eczema, senile pruritus, pediculosis, nodular prurigo, and herpes zoster).
Treatment: Single or localized lesions should be soaked for 10 min in a drying agent such as Burow’s solution (aluminum acetate 5%). Extensive lesions require systemic antibiotics to reduce the risk of glomerulonephritis and prevent impetigo from spreading. A skin swab should be taken for microbial culture and sensitivity assays.
Patients with streptococcal pyoderma should be treated with penicillin V 250 to 500 mg orally qid for 10 days. If patient compliance is unlikely, long-acting penicillin G benzathine 1.2 million u. IM may be necessary. If the patient is allergic to penicillin, erythromycin 250 to 500 mg orally qid can be given. Patients with staphylococcal pyoderma should receive dicloxacillin 250 to 500 mg orally qid for 10 days.
Staphylococcal Scalded Skin Syndrome
(Ritter’ s Disease)
A severe, extensive bullous condition caused by a staphylococcal skin infection, in which the epithelium lifts off in sheets leaving large denuded areas. Although generally a disease of young children, the condition is increasingly appearing in immunocompromised adults. In elderly patients, staphylococci usually invade the skin and the blood, and death usually results from septicemia.
Toxic epidermal necrolysis, an adverse drug reaction that can produce an identical clinical picture, must be considered in the differential diagnosis. Both these conditions are life threatening and require hospitalization. To differentiate between staphylococcal scalded skin syndrome and toxic epidermal necrolysis, the examiner observes a frozen section from a skin scraping or biopsy to determine the level of cleavage. In staphylococcal scalded skin syndrome, cleavage occurs within the epidermis just below the granular layer. In toxic epidermal necrolysis, subepidermal blister formation occurs with basal cell damage. Differentiation is important because staphylococcal scalded skin syndrome must be treated immediately with penicillinase-resistant antistaphylococcal antibiotics.
Treatment: Therapy is the same as for severe burns, beginning with immediate fluid and electrolyte replacement. A systemic antibiotic (eg, IV oxacillin) should also be given promptly. The source of infection may be difficult to isolate, but culture specimens should be taken from the skin, blood, nares, and any other suspected sites. Silver sulfadiazine cream may help prevent cutaneous superinfection with gram-negative bacteria. Even with treatment, the prognosis is poor.
Erysipelas
A superficial infection of the skin caused by group A or group C hemolytic streptococci. The organisms may enter the skin through minor cuts, wounds, or insect bites.
The affected area may be red and swollen. The lesions have well-defined margins that advance as the infection spreads. Vesicles or bullae may be present, and in the elderly, hemorrhage may occur. Fever, malaise, and lymphadenopathy may also develop.
Treatment: Penicillin V or erythromycin 250 to 500 mg orally qid should be given for 2 wk. Because the infection continues to spread during the first 12 to 24 h of oral therapy, patients with facial lesions often require hospitalization and IV antibiotics to prevent cavernous sinus thrombosis.
Cellulitis
A deep infection of the skin, most frequently caused by group A streptococci and occasionally by gram-negative organisms. In the elderly, cellulitis most commonly occurs as a complication of an open wound, such as a venous ulcer. However, it also develops in intact, edematous skin, especially in the legs. Erythema, tenderness, swelling, warmth, and lymphadenopathy may be present.
Treatment: Penicillin or erythromycin 250 to 500 mg orally qid should be given for 2 wk. If the lesion is large or near a vital structure or if the patient has fever, diabetes mellitus, or peripheral vascular disease or cannot be closely monitored, initial IV therapy is recommended. In some patients, cellulitis responds slowly to antibiotics, and prolonged treatment is needed.
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.
YEAST INFECTIONS
Candidiasis
An infection caused by the yeast Candida albicans, which thrives in warm, moist areas such as the groin, the axilla, and the submammary region. Diabetic and immunosuppressed patients, as well as those receiving systemic antibiotic therapy, are at increased risk. The organism may be carried asymptomatically in the bowel, mouth, and vagina, causing treated sites to become reinfected.
Candidal vulvovaginitis is manifested by pruritus vulvae, vulvar erythema and edema, and a creamy vaginal discharge. Patients with these signs should be tested for glycosuria because diabetes strongly predisposes patients to candidal infections.
Oral candidiasis (thrush) is characterized by creamy white plaques on the tongue or buccal mucosa, which can be easily scraped off.
Perleche (angular cheilitis) is a mixed bacterial and candidal infection of the corners of the mouth. The skin appears moist, cracked, and fissured. Predisposing factors include deep folds at the corners of the mouth, poorly fitting dentures, and retention of saliva and food particles in the affected areas.
Treatment: For vulvitis, miconazole 2% or clotrimazole 1% cream can be applied tid. For vulvovaginitis, a 100-mg clotrimazole vaginal insert can be applied once a day for 7 days. Nystatin vaginal suppositories can also be used (2 tablets of 100,000 u. each inserted high into the vagina every night for 14 nights). Nystatin cream should then be applied to the labia, perineum, and perineal area, after which the hands should be washed thoroughly.
For oral candidiasis or perleche, either nystatin or amphotericin B, available as mouthwashes and lozenges, can be used qid. Dentures should be soaked in nystatin suspension because they are invariably contaminated with C. albicans. Miconazole 2% or nystatin cream tid for 1 wk usually produces rapid improvement.
Intertrigo
A dermatitis, usually caused by maceration and exposure to irritants, occurring between two folds of skin—eg, between the buttocks, the thighs, or the scrotum and the thigh. Intertrigo often appears as moist, red, and sometimes scaly and pruritic areas in the flexures. Intense itching or soreness may develop from the groin to the perineum, in the inner thighs, and in the intergluteal cleft. Contributing factors include obesity, poor personal hygiene, and clothing made of synthetic fabrics that do not breathe.
Intertrigo may mimic or coexist with a candidal superinfection. Candida often produces so-called satellite lesions—small vesicles at the periphery of the lesion. Examination of a scraping prepared with KOH solution may reveal the characteristic budding yeasts and pseudohyphae.
Treatment: Affected areas should be kept as dry as possible. Topical antifungal creams (eg, clotrimazole 1% or miconazole 2%) should be applied tid if Candida is suspected. Nystatin cream, another anti-candidal agent, is not effective against dermatophytes and therefore should be used only when there is no suspicion of tinea infection. If inflammation is severe, a low-potency, topical corticosteroid cream (eg, hydrocortisone 1%) can be applied tid. Some available commercial preparations combine an antifungal agent and a topical corticosteroid cream, such as clotrimazole and betamethasone diproprionate cream.
VIRAL INFECTIONS
Herpes Zoster
(Shingles)
An acute eruption caused by a reactivation of latent varicella virus in the dorsal root ganglia of a partially immune host. Herpes zoster may occur at any age, but the peak incidence occurs between ages 50 and 70, and the age-specific incidence increases throughout life. Zoster usually affects otherwise healthy people, but immunosuppressed patients are at higher risk. The increased frequency among older persons may be explained partially by a decrease in cellular immune response to varicella-zoster antigen, which is undetectable in up to 30% of previously immune, healthy persons > 60 yr. Other factors that predispose persons to a reactivation of varicella virus include immunosuppressive drugs, corticosteroids, malignancy, local irradiation, trauma, and surgery. Herpes zoster recurs in about 6% of cases, usually at the same site as the initial episode.
The major difference between herpes zoster in the elderly and in young adults is the incidence of postherpetic neuralgia, which increases sharply with age to about 40% in those > 60 yr. The duration and severity of discomfort increase even more markedly with age than the incidence does. Other complications include encephalitis, ophthalmic disease, motor neuropathies, Guillain-Barre syndrome, and urinary retention.
Symptoms and Signs: The patient may develop prodromal symptoms of chills, fever, malaise, GI disturbance, and paresthesia or pain along the affected dermatome. The distribution of dermatomal zoster infections is 50% to 60% thoracic, 10% to 20% trigeminal, 10% to 20% cervical, 5% to 10% lumbar, and < 5% sacral. Rarely, prodromal symptoms persist for 5 to 7 days, leading to a variety of misdiagnoses from herniated disk to acute abdomen. Usually, red papules appear along a dermatome within 3 days. These eruptions rapidly develop into grouped vesicles, which vary in size, may be hemorrhagic, and may be extremely painful. After about 5 days, the vesicles begin to dry and form scabs; gradual healing occurs over the next 2 to 4 wk. Persistent hyperpigmentation or true scarring may result, particularly in the elderly.
In about 50% of patients with uncomplicated herpes zoster, some vesicles appear outside the affected area. However, if widespread severe dissemination occurs, an underlying lymphoma or other cause of immunodeficiency should be suspected.
Ophthalmic herpes zoster results from involvement of the ophthalmic division of the trigeminal nerve. Conjunctivitis, iridocyclitis, and keratitis may occur. In such cases, an ophthalmologic consultation should be sought. Lesions on the tip of the nose indicate involvement of the nasociliary and ophthalmic nerves. The risk of postherpetic neuralgia is greater than with involvement of other dermatomes.
Geniculate neuralgia (Ramsay Hunt syndrome) results from involvement of the geniculate ganglion. Facial paralysis (usually temporary) occurs, pain develops in the ear on the affected side, and taste is lost in the anterior two thirds of the tongue. Vesicles appear on the soft palate, fauces, and external auditory meatus on the affected side. Consultation with a neurologist is advisable.
Diagnosis: The finding of multinucleate giant cells on a cytologic smear or biopsy of a vesicle confirms the diagnosis. Although not commonly needed, electron microscopy and vesicle fluid culture can also identify the virus. However, false-negative results are common with vesicle fluid culture.
Treatment: A systemic corticosteroid (eg, prednisone 40 to 60 mg/day), started within a week of the eruption, appears to reduce acute symptoms and the risk of postherpetic neuralgia in elderly patients. Corticosteroids are the treatment of choice in patients with geniculate neuralgia (Ramsay Hunt syndrome).
If the patient is seen within 3 days of the onset of the eruption, oral or IV acyclovir is appropriate. This drug inhibits the development of new vesicles and decreases the duration of viral shedding and discomfort. Acyclovir also appears to decrease the risk of postherpetic neuralgia. The recommended oral dosage is 800 mg 5 times daily for 10 days. The IV dosage is 5 mg/kg q 8 h for 5 days.
Analgesia is usually needed, as well. Simple analgesics, such as acetaminophen or aspirin given q 4 h or nonsteroidal anti-inflammatory drugs may be sufficient, but some patients require more potent medication. However, opioids should be avoided if possible, especially in the elderly, because of the increased risks of adverse reactions and medication errors.
Topical treatment consists of soaking the affected areas in Burow’s solution (aluminum acetate 5%), diluted 1:20 to 1:40, to remove vesicle crusts, decrease oozing, and dry and soothe the skin. Gauze dressings are soaked in the solution, applied to the affected areas, and loosely bandaged. The dressings are changed q 2 to 3 h. If impetigo develops, systemic antibiotics should be given (see BACTERIAL INFECTIONS, above).
Until dry crusts appear, herpes zoster lesions contain infectious viral particles. A person who has never had varicella may develop it after direct contact with the lesions or with moist, contaminated dressings. Usually, only young children are susceptible. However, because varicella virus is teratogenic in early fetal development, pregnant women should avoid contact with zoster patients. Severely immunocompromised patients should also avoid exposure. Ordinarily, isolating zoster patients from casual contact with other adults is not necessary, however.
PARASITIC INFECTIONS
Scabies
An eruption caused by a mite, Sarcoptes scabiei. The female mite burrows into the skin and deposits eggs, which hatch into larvae in a few days. Scabies is easily transmitted by skin-to-skin contact and can be rapidly spread between residents of the same household, nursing home, or institution. Infestation is usually present for weeks before the patient becomes allergically sensitized to the insects and develops itching.
Symptoms and signs: Eventually the patient experiences intense pruritus, which usually worsens at night. On examination, the skin is usually excoriated. The characteristic sign is the burrow—a linear ridge with a vesicle at one end—where the mite is usually found. Burrows are common in the interdigital webs, the flexor aspects of the wrists, the axillae, the umbilicus, around the nipples, and on the genitalia. Erythematous papules or nodules in the same areas are also common.
In the elderly, scabies may present less typically, especially if untreated for a long time. The condition may mimic eczema or exfoliative dermatitis because widespread thick crusted lesions are present. The patient may have erythroderma and generalized lymphadenopathy.
Diagnosis and treatment: A mite at the end of a burrow can sometimes be excavated with a needle or a scalpel blade, placed in a drop of mineral oil, and detected under a microscope. However, even in long-term cases with widespread excoriations, few mites are present, and they may be impossible to find. Therefore, treatment is usually based on a
presumptive diagnosis.
A lotion or cream containing lindane 1% should be applied to the entire body from the neck down. All patients need help applying the medication and must understand that all areas must be covered. After 24 h, the patient should bathe; all clothes and bed linens should be machine-laundered in hot water or dry-cleaned.
A second application of the cream or lotion, also left on the body for 24 h, should be made 7 days later to kill any newly hatched larvae. Itching, which results from allergic sensitization and not from viable organisms, may not subside until 1 to 2 wk after treatment. However, itching can be effectively treated with topical corticosteroids or, in severe cases, with a tapering course of oral corticosteroids.
All household members and close personal contacts should also be treated. In a nursing home, all clinical staff, patients, and their household contacts should be treated on the assumption that some infested persons are still asymptomatic.
Pediculosis
(Lice)
Lice may infest the head (Pediculus humanus capitis), the body (P. humanus corporis), or the genital area (Phthirus pubis). Elderly people who have poor personal hygiene or who live in an overcrowded environment are at risk for head and body lice.
Pediculosis capitis is spread by personal contact or by sharing hairbrushes and head wear. The patient develops severe scalp itching, often with secondary eczematous changes and impetiginization. Cervical lymphadenopathy may occur. Examination reveals small gray-white nits (ova) on the hair shafts. Unlike scales, they cannot be easily removed. Adult lice are not usually found.
Pediculosis corporis produces intense generalized itching. The patient frequently develops eczematous changes, severe excoriations, and a secondary bacterial infection. Lice or nits may be found in the seams of the patient’s clothing.
Pediculosis pubis is usually spread by sexual contact but can be transferred by clothing or towels. The base of pubic hairs should be carefully searched for lice and their eggs. Sometimes, dark brown particles (louse excreta) may be seen on underclothes.
Treatment: For head lice, shampoo containing lindane 1% is applied to the scalp, left in place for 4 min, and rinsed off. The patient should then comb the hair with a fine-tooth comb. The procedure should be repeated in 10 days to destroy any remaining nits. Combs and brushes should be soaked in the shampoo for 1 h.
For body lice, the patient’s clothing should be boiled, dry-cleaned, or machine washed with hot water. The seams of the clothing should be pressed with a hot iron. Alternatively, the clothing can be disinfected with an insecticidal powder such as DDT 10% or malathion 1%. Because lice do not remain on the host after feeding, the patient’s skin requires therapy only for irritation and pruritus.
For pubic lice, 1% lindane shampoo is applied to the pubic area for 4 min, then rinsed off. This treatment should be repeated in 10 days.