There are a number of diseases causing loss of skin color with the appearance of white patches on the skin surface.
Loss of skin color is due to the decrease of the melanin pigment within the skin. This may occur either due to a decrease or absence of the melanocytes, which are the cells in the epidermal layer of the skin producing the melanin, or due to a decrease in the production of melanin due to various causes.
This group of disorders of skin color may be classified according to the causes or clinical appearance of the skin patches.
Classification of White Patches on the Skin According to the Causes
- Genetic: Complete or partial loss of skin color is seen in many genetic diseases. Off white to totally white patches are present in albinism, nevus depigmentosus, hypomelanosis of Ito, nevus anemicus, tuberous sclerosis, piebaldism, Vogt Koyanagi Harada syndrome, Waardenburg’s syndrome, to name a few.
- Autoimmune: Auto antibodies against melanin destroy the pigment cells resulting in totally white patches in the skin. Vitiligo is a classical example.
- Post-Inflammatory: Chemical leukoderma, psoriasis, leprosy, pityriasis versicolor, pityriasis alba, mycosis fungoides
- Compensatory: Halo nevus, vitiligo associated with melanoma.
- Drug Induced: Fluorinated and potent topical steroids and intralesional steroids and depigmenting creams like hydroquinone.
Clinical Classification of Diseases Causing Loss of Skin Color
- Hypopigmentary Disorders: There is only partial loss of pigmentation here. Common examples are tinea versicolor and pityriasis alba.
- Depigmented Disorders: Complete loss of pigmentation, as in vitiligo.
What is the Difference Between Vitiligo and Leukoderma?
Vitiligo is an autoimmune loss of color of the skin due to unknown causes. Leukoderma (leucoderma) is the loss of pigmentation secondary to an inflammatory cause, due to chemicals or allergic reaction to some medications.
Common Diseases Causing White Patches on the Skin
Following are some of the common illnesses causing white patches on the skin:
- Tinea versicolor. Superficial yeast infection caused by Malassezia furfur. Flat, white patches with delicate scales, at times dark brown or light brown patches appear on the upper body and face usually.
- Pityriasis alba. Off white color mostly on the face in children. Usually associated with atopic dermatitis and dry skin, the exact cause of pityriasis alba is not known. It is thought to be a hypersensitive response to nutritional deficiency, worm infestation and/or sun rays.
- Vitiligo. A major cosmetic problem in the brown and dark skinned, the patches in vitiligo are totally white, though the early patches are off white. The skin surface is smooth and devoid of any scaling.
- Post inflammatory leukoderma. Off white or depigmented patches appearing after the healing of active rashes of diseases like psoriasis, eczema, pityriasis rosea or contact allergic dermatitis is known as post inflammatory leukoderma.
- Leprosy (Hansen’s Disease). Dry, scaly, off white skin patches with sensory impairments and associated thickening of the peripheral nerves is the hallmark of some types of leprosy, caused by the bacteria mycobacterium leprae.
- Drug induced. Treatment with potent topical steroids can cause complete or partial loss of pigmentation in the skin. Intralesional injection of steroids for tendon or articular pain results in depigmented patches in the area after a few days. Topical application of hydroquinone can also lead to hypo pigmentation in the normal skin. Mono benzyl ether of hydroquinone can cause permanent loss of melanin pigment in the skin leading to leukoderma.
- Mycosis fungoides or cutaneous T cell lymphoma. Early skin rashes of mycosis fungoides are scaly or non scaly white or pink patches. The surface is papery thin and shiny to start with, gradually thickening to form plaques and nodules within the skin.
The multiple causes of white patches makes early diagnosis mandatory in conditions like mycosis fungoides and leprosy.
Related Article
Reference
- Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology, Fifth Ed, 2005
The copyright of the article Diseases Causing Loss of Skin Color in Skin Discoloration is owned by Hanish Babu. Permission to republish Diseases Causing Loss of Skin Color in print or online must be granted by the author in writing.
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