A Guide To Dry Skin Disorders In The Lower Extremity

Author(s): 
M. Joel Morse, DPM

   Xerosis. Xerosis results in generalized or localized pruritus and dry, itchy skin. Rubbing and scratching causes increased irritation, leading to more pruritus and inflammation.14

   Lichen simplex chronicus (neurodermatitis). Prolonged itching and scratching can lead to skin that is thick, scaly and leathery. The patches can be raw, red or darker than the rest of your skin.

   Stasis dermatitis (venous eczema, varicose eczema). Stasis dermatitis is not “true” dermatitis but instead is due to venous hypertension in the lower leg. This is caused by insufficiency of the superficial veins as well as the long saphenous vein. One study found that when patients received classical flush ligation and a saphenectomy, lower leg dermatitis healed in all 10 patients within eight to 12 weeks, and there was no recurrence.15

   Eczema craquelé (winter itch, asteatotic eczema, xerotic eczema, desiccation dermatitis). Eczema craquelé occurs mostly in elderly individuals with tight, red, dry skin that progresses to superficially fissured dermatitis. The irregular network of fissures resembles a dry riverbed and is visible on the shins of legs. This is essentially “advanced” xerosis.9

   Atopic dermatitis. In this form of eczema, one has more sensitive and drier skin due to an autoimmune condition.

   Psoriasis. Psoriasis involves the rapid buildup of rough, dry, dead skin cells that form thick scales. These scales bleed when patients pick them off. It occurs mostly on the plantar skin in the foot.

Which Came First, Dry Skin Or The Itch?

Dry, “flaky” skin is an irritant and causes cutaneous inflammation, which in turn results in pruritus. Once the itch-scratch-itch cycle starts, the skin gets worse. The inflammation irritates the nerve endings.16 Treatment of dry skin is one of the most important measures against pruritus.17 Prevention is very important.

   Researchers have rarely found correlations between itch and objective measures of barrier function and skin dryness such as skin hydration and transepidermal water loss. Recent experimental evidence indicates that damage to the stratum corneum with acetone/ether and water elicits a scratching response in mice and rats.18 Skin diseases associated with itch include eczema, atopic dermatitis, dry skin, contact dermatitis, psoriasis, lichen planus and bacterial infection.

   Topical treatments for itch/dry skin:

Polidocanol (Asclera, Merz Aesthetics)
Capsaicin
Menthol
Phototherapy
Lotions and creams
Steroids
Systemic treatments for itch/dry skin:
Antihistamines
Antidepressants
Gabapentin (Neurontin, Pfizer)
Opiate antagonist

Keys To Diagnosing Dry Skin

For the most part, dry skin is a purely clinical diagnosis. A thorough history, review of systems and physical examination are critical to determining its cause. Examination of the skin may be misleading. There are frequently only secondary lesions, eczematous changes, lichenification and excoriation, and the inciting cause may not be present. If primary lesions are present, a skin biopsy can lead one to a diagnosis. One must consider systemic causes of dry skin/itch, such as cholestasis, uremia, hyperthyroidism, medications or lymphoma.

   However, if the normal topical treatments are not resolving the condition, have the lab test for thyroid function, renal function, liver function, HIV, zinc level, cancer, or Sjögren’s syndrome.

Treating Dry Skin

The first step to treat dry skin is to add water to the skin and apply a hydrophobic substance to keep it there. The substances include water-in-oil creams and lotions or 100% oil ointments to lock in the water. No matter what the cause of dry skin is, occlusive moisturizers, humectant emollients and keratolytics are three commonly used topical treatments.

   For the most part, emollients work by retaining water in the skin where it is needed and enabling the repair of damaged cells on the skin’s surface. Emollients also act as a barrier to the environment, preventing irritants from penetrating the outer layer of the skin (epidermis) by creating a protective lipid film.3

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