Why Is My Skin Always So Dry?
A 71-year-old man presented to the office because of dry skin. He said that since he was a child, he always had flaky, dry skin that covered almost his entire body. Although he had been prescribed many types of lotions and ointments during his lifetime, none relieved nor worsened his dry skin. The patient reported no redness or pruritus. To his knowledge, there was no family history of anyone having the same symptoms. The man had a 59-pack-year history of smoking and his medical history included basal cell carcinoma, hypertension, and peripheral arterial disease, for which he had undergone peripheral arterial bypass surgery. Upon physical examination, he had dry, flesh-colored, polygonal scales covering his entire body, particularly on his arms and legs (Figures). At the time, he was using prescribed desonide topical lotion, mupirocin topical ointment, and urea topical cream. He was also taking clopidogrel to prevent blood clots.
Based on the photographs and the case description, what is your diagnosis?
A. Asteatotic eczema C. Ichthyosis vulgaris
B. Lichen simplex chronicus D. Contact dermatitis
Answer and Discussion on next page
Diagnosis: Ichthyosis vulgaris (C)
Ichthyosis is a dermatological condition in which the skin forms fine, fish-like scales on the extensor surfaces of the limbs, trunk, and scalp.1 Typically, this disease is inherited and becomes apparent within the first year of life, when desquamation (ie, peeling) of the skin is observed.1,2 There are several different types of ichthyosis, including ichthyosis vulgaris, X-linked ichthyosis (which occurs only in men), lamellar ichthyosis, and epidermolytic hyperkeratosis.1 While the exact prevalence of ichthyosis vulgaris in the geriatric population is not known, the estimated prevalence in the adult population is one in 250 individuals, making it one of the most common keratinization disorders.3
Ichthyosis vulgaris is an autosomal dominant form of ichthyosis with variable penetrance.1 Other conditions often seen in those with ichthyosis vulgaris are atopic dermatitis and keratosis pilaris, as well as increased palmar creases.2 While many causes are associated with acquired ichthyosis, including malignancies, autoimmune disorders, and use of certain drugs, congenital ichthyosis vulgaris is present at birth.4 There are no known risk factors or predictors to identify persons who may be born with this condition. Ichthyosis vulgaris is caused by mutations in the filaggrin gene.5 The alterations resulting from these mutations cause a reduction in keratohyalin granules in the epidermis.5 The reduction in granules leads to hyperplasia of the epidermis with increased bundles of corneocytes, and as a result, there is the characteristic desquamation of the skin.5
Obtaining a good biopsy specimen can help differentiate autosomal dominant ichthyosis vulgaris from other conditions. For the best biopsy results, specimens should be obtained in regions of maximum scaling, such as the leg, where scales tend to be thicker. Samples taken from the arm, where scales are more delicate, may be similar microscopically to normal skin. Our patient’s biopsy revealed characteristic mild hyperkeratosis and a diminished granular layer in the epidermis, while the dermis had normal features. These findings, along with the classic clinical findings of fish-scale ichthyosis, led to the diagnosis of ichthyosis vulgaris, and treatment options were discussed with the patient.
Approaches to Treatment
Ichthyosis vulgaris often improves on its own as an individual ages.6 An effective treatment for this condition is combination therapy with ammonium lactate lotion and a lipid-based barrier repair cream that contains ceramides, cholesterol, and free fatty acids.1 Urea cream is another effective treatment, and topical retinoids and vitamin D ointment can also be therapeutic.6 In addition, applying a noncomedogenic moisturizer can help the epidermis retain moisture.6 Our patient was treated with 12% ammonium lactate lotion. The lotion helped to moisturize his skin by acting as a humectant in addition to stimulating the synthesis of ceramide, a lipid molecule that contributes to about half the mass of the skin permeability barrier.5
Ruling Out the Other Diagnoses
What follows is a discussion of some of the other possible diagnoses, which were ruled out for our case patient.
Lichen Simplex Chronicus
Thickening of the skin can occur on any part of the body where there is perpetual scratching. Lichen simplex chronicus is a form of eczema that manifests as an erythematous plaque resulting from constant friction. Areas of lichenification brought about by constant scratching are commonly seen around the wrists and ankles, extensor forearms near the elbow, the lower portions of the legs, and near the scrotum and vulva areas,6 as these areas are within hand’s reach.1 The inflicted scratching can be caused by insect bites, atopic dermatitis, or can even be psychological in nature.1
Asteatotic eczema, often seen on the anterolateral areas of the lower legs in elderly persons, is an inflammatory skin reaction that is also known as eczema craquele.6 Dry environments, such as those brought on by the winter months, worsen the dryness of the skin. When the skin becomes abnormally dry, the condition is referred to as xerosis, and this can cause asteatotic eczema comparable to the subacute eczema seen in stasis dermatitis.6 Irritation of the skin increases as the skin continues to dry out, worsening the prominence of the lines in the skin that are exacerbated as the patient continues scratching the area. These lines in the skin also form fissures inside erythematous plaques around the affected areas, and they often become purulent.6 Factors that might increase the likelihood of an individual developing the fissures that are part of asteatotic eczema depend on their overall state of health, the presence of various diseases, the medications taken to treat those diseases, and the weather.7
Examples of conditions that tend to correlate with developing asteatotic eczema include asthma and atopic dermatitis.7 The chance that an individual will develop xerosis increases significantly with age because of the skin’s inability to stay hydrated.4 Asteatotic eczema is more common in women and older adults.7
When an individual is allergic to certain irritants, a delayed hypersensitivity reaction occurs on the skin in the form of an eczematous dermatitis.1 Contact dermatitis can be divided into two forms: irritant contact dermatitis and allergic contact dermatitis. Allergic contact dermatitis often arises after irritant contact dermatitis.8 There are many types of irritants that commonly cause contact dermatitis, including neomycin, rubber chemicals, and some ingredients found in cosmetics.1 Contact dermatitis can appear differently throughout the acute and subacute phases. During the acute phase, the lesions appear as vesicles, while in the subacute phase, the lesions are more erythematous and scaly.1
Individuals with an increased sensitivity to allergens are more likely to develop allergic contact dermatitis, whereas irritant contact dermatitis is seen more commonly within the general population. Stasis dermatitis is one of the acquired risk factors for allergic contact dermatitis.8 One way to diagnose contact dermatitis is with the use of patch testing. Often the diagnosis is made clinically by the distribution of the rash. If there is an inciting allergen that is causing the dermatitis, it is important that it be removed so that the condition improves.
Dr. Norman is in private practice in Tampa, FL. He is also associate professor, University of Central Florida School of Medicine, Orlando, and at Nova Southeastern School of Medicine, Davie, FL. Ms. Aun is a third-year student of osteopathic medicine at Lake Erie College of Osteopathic Medicine, Bradenton, FL.
The authors report no relevant financial relationships.
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