Hypopigmentation is a decrease in normal skin, hair, mucous membrane, or nail color resulting from deficiency, absence, or abnormal degradation of the pigment melanin. This sign may be congenital or acquired, asymptomatic or associated with other findings. Its causes include genetic disorders, nutritional deficiency, chemicals and drugs, inflammation, infection, and physical trauma. Typically chronic, hypopigmentation can be difficult to identify if the patient is light-skinned or has only slightly decreased coloring.
Begin with a detailed patient history. Ask if any other family member has the same problem and if it was present from birth or developed after skin lesions or a rash. Were the lesions painful? Does the patient have any medical problems or a history of burns, physical injury, or physical contact with chemicals? Is he taking prescription or over-the-counter drugs? Find out if he has noticed other skin changes—such as erythema, scaling, ulceration, or hyperpigmentation—or if sun exposure causes unusually severe burning.
Next, examine the patient’s skin, noting erythema, scaling, ulceration, areas of hyperpigmentation, and other findings.
This genetically inherited disease involves alterations of the melanin pigment system that affects skin, hair, and eyes. There are various forms of albinism, all of which are present at birth. Skin and hair color vary from snow white to brown, but the universal finding of iris translucency confirms the diagnosis. Associated eye findings include nystagmus, decreased visual acuity, decreased pigmentation of the retina, and strabismus.
Lifelong diligence is needed to protect the skin from sun exposure, including using sunblock with an SPF greater than 30; wearing protective clothing, hats, and sunglasses (even for infants); avoiding the sun during high solar intensity; and obtaining routine skin examinations for the development of skin cancers.
Suggest referral to a support group to assist patients with problems occurring in daily life. One such organization is the National Organization for Albinism and Hypomelanosis (NOAH).
Thermal and radiation burns can cause transient or permanent hypopigmentation.
This form of lupus erythematosus may produce hypopigmentation after inflammatory skin eruptions. Lesions are sharply defined, separate or fused macules, papules, or plaques; they vary from pink to purple, with a yellowish or brown crust and scaly, enlarged hair follicles. Although they may occur on other parts of the body, the lesions are typically distributed in a butterfly pattern over the cheeks and bridge of the nose. Telangiectasia may occur. After the inflammatory eruptive stage, noncontractile scarring and atrophy commonly affect the face and may also involve sun-exposed areas of the neck, ears, scalp (with possible alopecia), lips, and oral mucosa.
Common in lightly pigmented people older than age 30, this skin disorder produces sharply marginated, angular white spots on sun-exposed extremities. In blacks, hypopigmentation occurs mainly on the upper arms.
Skin disorders, such as psoriasis, and infectious disorders, such as viral exanthemas or syphilis, can cause transient or permanent hypopigmentation.
This benign fungal skin infection produces scaly, sharply defined lesions that usually appear on the upper trunk, neck, and arms. The lesions range from hypopigmented patches in dark-skinned patients to hyperpigmented patches in fair-skinned patients.
This chronic disorder affects the skin and peripheral nervous system. Erythematous or hypopigmented macules have decreased or absent sensation for light, touch, and warmth. Because the lesions don’t sweat, the skin feels dry and rough; it may be scaly. Associated effects may include very painful, palpable peripheral nerves; muscle atrophy and contractures; and ulcers of the fingers and toes.
This common skin disorder produces sharply defined, flat white macules and patches ranging in diameter from 1 to over 20 cm. The hypopigmented areas commonly have hyperpigmented borders. Usually bilaterally symmetrical, lesions appear on sun-exposed areas; in body folds; around the eyes, nose, mouth, and rectum; and over bony prominences. Patches of vitiligo may coalesce to form universal lack of pigment and may involve the hair, eyebrows, and eyelashes. Spontaneous repigmentation can occur. Hypopigmented patches (halo nevi) may surround pigmented moles.
Most phenolic compounds—for example, amylphenol (a dye) and paratertiary butylphenol (PTBP), which are used in plastics and glues, and germicides used in many household and industrial products—can cause hypopigmentation.
Topical or intralesional administration of corticosteroids causes hypopigmentation at the treatment site. Chloroquine, an antimalarial drug, may cause depigmentation of hair (including eyebrows and lashes) and poor tanning 2 to 5 months after therapy begins.
In fair-skinned patients, a special ultraviolet (UV) light (Wood’s lamp) can help differentiate hypopigmented lesions, which appear pale, from depigmented lesions, which appear white.
Advise patients to use corrective cosmetics to help hide skin lesions, and to use a sunblock because hypopigmented areas may sunburn easily. Encourage regular examinations for early detection and treatment of lesions that may become premalignant or malignant. Repigmentation therapy may be prescribed, combining a photosensitizing drug (psoralen) and UV light, wavelength A. Advise patients with associated eye problems, such as albinism, to avoid the midday sun and to wear sunglasses. Refer patients for counseling if lesions cause stress.
In children, hypopigmentation results from genetic or acquired disorders, including albinism, phenylketonuria, and tuberous sclerosis. In neonates, hypopigmentation may indicate a metabolic or nervous system disorder.
In elderly people, hypopigmentation is usually the result of cumulative exposure to UV light, which may also cause hyperpigmentation, telangiectasia, and purpura. These changes are known as dermatoheliosis.
Review other book chapters online related to Hypomelanosis of Ito:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Professional Guide to Signs & Symptoms (Fifth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2006 ISBN: 1-58255-510-9 
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