Noah S. Scheinfeld, MD, JD

Certain papulosquamous and bullous diseases are more common in older adults than in younger persons. For example, bullous pemphigoid typically affects those in the fifth through seventh decades of life. Grover disease, or transient acantholytic dyskeratosis, is most common in white men older than 65.

Inside: a photo guide to the various manifestations of stasis dermatitis, irritant contact dermatitis, and allergic contact dermatitis-including diagnostic clues and treatment options.

Physical changes that occur in aging skin (eg, dryness and thinning) can result in pruritus and cause patients to rub, scratch, and pick at their skin. These activities produce various dermatoses and reactive changes in the skin, such as postinflammatory pigmentary alteration. Lichen simplex chronicus (LSC) develops as a physiological cutaneous response to repetitive scratching or rubbing. First-line treatment consists of topical corticosteroids and application of ice to reduce the sensation of itching. Like LSC, prurigo nodularis results from rubbing and scratching the skin. Treatment is similar; however, intralesional corticosteroids and UV therapy play more of a role because prurigo nodularis is more intensely pruritic than LSC.

A 37-year-old man presents with moderately pruritic urticarial papules on areas of his skin that are not covered by his shorts and T-shirt. He recently returned from a trip to Upstate New York, where he had stayed in several rustic cabins that were used by different people daily.

A number of factors heighten the risk of parasitic infections in elderly persons, who often live in communal settings (eg, nursing homes), where they are more likely to encounter parasites, such as the scabies mite.

Tinea corporis appears as an annular plaque with a rim of scaly erythema.

Tinea that occurs on the hands is referred to as tinea manuum.

Maceration or scale between isolated web spaces of the fingers suggests erosio interdigitalis blastomycetica (interdigital candidiasis). It most often occurs in the web space between the middle and ring fingers; sometimes the toes are affected. Erosio can spread and can be painful.

A fungal folliculitis (Majocchi granulomas) can occur if a superficial fungal infection is treated with topical corticosteroids. Fungal folliculitis is best treated with a short course of oral itraconazole or fluconazole.

Candidal infection can also occur at the lateral angles of the mouth; it causes erosions and breakdown of the skin. Angular cheilitis, or perleche, resembles the relationship between intertriginous candidiasis and intertrigo in that it is part infection and part inflammatory response to the impairment of epidermal integrity.

Tinea that occurs on the hands is referred to as tinea manuum. For unknown reasons, tinea often affects two feet and one hand. Tinea manuum must be distinguished from allergic contact dermatitis of the hands, which it resembles; this can be done by examination of a potassium hydroxide preparation. Tinea manuum can be treated with a topical antifungal agent.

This infection is usually caused by Candida albicans, whichis often present in body folds. Candidiasis is common in persons with diabetes and in obese persons. Other predisposing factors are the use of antibiotics, topical corticosteroids, or immunosuppressive drugs; poor nutrition; and immunosuppression.

Tinea pedis, or athlete's foot, is common in elderly persons. It manifests as maceration in the interdigital web folds and as scaly plaques on the plantar surfaces of the feet. A potassium hydroxide evaluation can establish the diagnosis. Tinea pedis is commonly associated with xerosis. It is best treated with a topical antifungal agent; treatment can be aided by a keratolytic such as lactic acid 12% cream.

Oral candidiasis, or thrush, is not uncommon in elderly persons. It can be related to poor dentition or immunosuppression, particularly as a result of oral corticosteroid use.

Tinea corporis occurs most often on the torso of elderly persons. It commonly appears as an annular plaque with a rim of scaly erythema. Occasionally, tinea corporis manifests with polycyclic annuli or with nummular plaques, which mimic nummular dermatitis. The examination of a potassium hydroxide preparation can establish the diagnosis. Tinea corporis can be treated effectively with a topical antifungal agent.

The prevalence of onychomycosis increases with age; it is less than 1% in persons younger than 19 years and rises to about 18% in those who are 60 to 79 years. The infection is more common in men than in women. Among the predisposing factors are diabetes mellitus, psoriasis, a family history of onychomycosis, use of immunosuppressive drugs, and peripheral vascular disease.

This infection is caused by reactivationof varicella-zoster virus (VZV),which may remain latent in thedorsal root and cranial nerve gangliafor decades. Reactivation oftenoccurs for no apparent reason, althoughstress and immunosuppressionmay increase the risk.

This infection is caused by reactivationof varicella-zoster virus (VZV),which may remain latent in thedorsal root and cranial nerve gangliafor decades. Reactivation oftenoccurs for no apparent reason, althoughstress and immunosuppressionmay increase the risk.

This polymicrobial infection, characterized by rapidly advancing deep tissue necrosis, is caused by Gram-positive and Gram-negative bacteria and anaerobes such as Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa.

Furunculosis is a deeper infection of the hair follicle generally attributable to S aureus.

Declining cardiovascular function, poor circulation, diabetes, obesity, cancer, immunodeficiency, renal disease, and thinned, xerotic skin provide the setting for a host of bacterial infections in elderly persons that can involve any level or structure of the skin.

This vesiculopustular eruption manifests with honey-colored crusted erosions. As it resolves, the crusts can turn brown; hyperpigmentation and scale may be evident.

Folliculitis, which features vesicles filled with white blood cells (pustules), usually affects hair-bearing sites, such as the scalp, neck, beard area, axillae, buttocks, and limbs.

Seborrheic keratoses are the most common neoplasms in elderly persons and affect up to 60% of this population. Risk factors for these lesions are thought to include genetic predisposition, age, and sun exposure.

Squamous cell carcinoma (SCC), the second most common type of skin cancer, most often occurs on the sun-exposed skin of elderly men and women. Marjolin ulcers are SCCs that result from exposure to radiation and can arise in areas of chronic injury, typically on the extremities.

Basal cell carcinoma (BCC) is the most common cancer in the United States; more than 1 million cases are reported annually. BCC is a carcinoma of aging and usually manifests in areas of chronic sun exposure.

Photo Quiz: Wart or Mimic? Part 2

Nongenital cutaneous warts--that is, common, plantar, filiform, and flat warts--are manifestations of the human papillomavirus (HPV). These warts are among the most common dermatologic complaints seen in primary care practices and are among the most common lesions treated by dermatologists.

During a routine examination, an asymptomatic wartlike lesion is noted near the axilla of a 35-year-old woman. The patient says that it has been present since childhood.

Nail involvement can be seen in all types of psoriasis. Note the characteristic discoloration and hyperkeratosis.