Skin cells called melanocytes produce pigment giving the skin its colour. If melanocytes disappear or is not produced or produced less, the skin loses its colour. "White spots appear".
In people, the causes are:
1. Pityriasis versicolor (white spot disases), body and limbs, mild itchiness. The acids secreted by yeasts - Malassezia, inhibit melanocytes from making melanin. Selenium sulphide solution and clotrimazole cream are common treatments. Oral anti-fungal medication for severe cases. Recovery of normal skin pigmentation may take many months.
2. Vitiligo is a skin disordr. Melanocytes are destroyed. The skin is usually completely white and clearly demarcated from the surrounding normal skin.
3. Idiopathic guttate hypomelanosis are 2-4 mm flat pale spots on the face, arms and legs. Extnesive and chronic sun exposure causing skin damage.
4. Post-inflammatory hypopigmentation - previous skin injury. Pigment temporary disappear. After vaccination or injection in the dog or cat.
5. Chronic arsenic poisoning. Rare cases where contaminated well water or traditional Chinese medicines containing arsenic is consumed for a long time.
6. Hypopigmented mycosis fungoides is a form of skin cancer. White patches on the body. Uncommon. Slow progress
Skin colour may take several months to recover after successful treatment.
In Toa Payoh Vets, the number one skin disease in dogs is ringworm which is curable.