Pityriasis alba is a mild dermatitis (skin inflammation) characterised by multiple oval, mildly scaly, flat hypopigmented (white) patches on the face, arms and upper trunk. The borders of these patches are indistinct. It occurs in children between the ages of 3 and 16 years and up to 30% of children may be affected during their childhood. The patches are not itchy. The condition is often mistaken for a fungal infection, and tends to become more prominent by sun exposure.
The cause is unknown, but there is recent evidence suggesting a virus to be the cause. Pityriasis rosea is, however, not contagious. Interestingly, the rash usually occurs only once in a lifetime.
Pityriasis rosea often begins with a single large, scaly, pink patch on the trunk, called a "herald" patch.
A widespread rash usually follows one to two weeks later. The rash occurs on the trunk, limbs and neck, but rarely involves the face. The typical rash consists of small, oval pink to brown scaly patches arrange along the skin creases, giving an appearance of a 'Christmas tree' on the back.
They come up in crops, at intervals of a few days for the first one to two weeks. The rash is itchy in about half of the affected patients. It usually fades and disappears within six to eight weeks, but can sometimes last much longer. The patient is often otherwise well throughout the course of the rash.
The rash will usually fade without leaving marks but they may leave light or dark patches in people with dark skin, but these marks will also eventually fade.
This is a harmless condition. It can last for months to years with slow spontaneous recovery. Sometimes, steroid creams may help. Avoid self medication. Avoid antifungal creams. Avoid excessive washing of the skin with soaps.
