PITYRIASIS ALBA (SIMPLEX)
This particular type of Dermatitis often occurs on the faces of children and young adults between the ages of 3 and 16. It produces mild, red & scaly patches and after subsiding leaves areas of hypopigmentation (lacking pigmentation).
The patches are often rounded or ovular in shape but occasionally can be irregular, often several patches appear at the same time, ranging in size from 0.5 to 2 cm in diameter, however larger patches may occur if the trunk is also affected.
Up to 20% of patients will present with patches, in addition to the face, on the neck, arms & shoulders. A minor percentage of these will also present on areas of the trunk and thighs. Although mildly itchy it is mainly the loss of colour in dark skinned (either heavily pigmented or very suntanned) patients that causes the most concern, as the lesions are extremely conspicuous. Whereas in lightly pigmented patients these lesions may only be noticeable after sun tanning.
Misdiagnosis, especially in heavily (dark) pigmented skin, of vitiligo may occur. However, unlike Vitiligo (where there is a permanent loss of pigment - depigmentation), it is extremely rare for the resulting patches of Pityriaris Alba to be permanent and children will eventually outgrow the condition.
The patches may, however, persist for several months and it is not unknown for the pale areas to be still visible for a year or more. Obviously it is far more noticeable in the summer months, when tanning occurs, so care should be taken to increase the use of sun block lotions.
PITYRIASIS VERSICOLOR or Tinea Versicolor
A superficial chronic fungal infection of the skin affecting usually the scalp or areas involving dense distribution of sweat glands, such as the chest and back but it has been known to also spread to the upper arms, neck and abdomen.
It occurs mainly in young adults living in hot and humid climates conducive to extreme sweating.
It presents in the form of roundish macules (flat pale white, pale red, yellowish-brown or dark brown patches) scattered over the body. Darker skinned people tend to have paler coloured lesions while lighter skinned people tend to have darker colours lesions. There may be slight itching, but the patches are usually small (nail-sized) and sometimes covered by a slight layer of fine scaling.
As this is a fungal infection it is contagious and people need to avoid close contact with either the patient or the patient's clothing. Hands, clothing, bedding and towelling should be disinfected.
Unlike Tinea Versicolor, which occurs mainly in summer and subsiding in Winter, Pityriasis Rosea occurs principally in the Winter. It affects children and young adults and usually involves the trunk, the armpit flexures and the flexures of the thigh and abdomen.
The condition initially develops as a single lesion (raised flat patch) on the trunk. One or two weeks later a second crop of smaller, miltiple lesions will apear on the trunk and sometimes the limbs.
The lesions present initially as pale red, yellowish-brown or reddish-brown in colour and later will develop a distinctive ”Rose” hue (hence the name), with a “ring of scale” along the inside edge of the lesion. The accompanying itch varies in intensity.
The condition will often clear spontaneously within a month or two of presenting. Recurrence of the condition is usually rare.
PITYRIASIS RUBRA PILARIS
A rare and chronic inflammatory disease that occurs mainly in children or young adults, recurring at regular intervals. But it has also been known to present in adults during their late twenties or even middle age.
It begins with a reddening of the face and scalp, with bran-like flaking. It can go on to involve the trunk and limbs and sometimes the entire body surface in very severe cases. In this situation it can often be confused with erythroderma (exfoliating dermatitis).
The condition presents as pink or red pinpoint follicular, keratotic papules (red, plugged, hair follicles). The skin is usually raised and coarse in texture. As the papules increase in number the redness merges to form large plaques. The skin on the palms and soles of the feet becomes yellow and thickened and fissuring appears. The fingernails and toenails may also thicken and become discoloured. The follicular plugging is especially noticeable on the dorsum (backs of the fingers). The skin may also begin to shed in layers and the hair on the scalp may become brittle and lose condition.
This condition can resolve spontaneously, just as mysteriously as it occurred. Unfortunately it can reoccur.
A rare skin disease that presents in two forms:
Chronic – similar to guttate psoriasis
Acute – where scarring occurs upon healing.
Chronic Varioliform Lichenoid Pityriasis
It affects more males than females and most frequently presents with the onset of puberty. Lesions appear on the trunk and limbs and the skin eruptions are pale red or reddish-brown. They vary in size, ranging from pinpoints to 5mm macules or maculopapule with slight, flat-topped, fluid filled blisters. The lesions are covered by a thin layer of adherent scales. The usual process is for the lesions to appear and heal in a cycle over several weeks.
New crops of lesions continue to develop throughout this period causing temporary altered patches of pigmentation, varying in colour, to appear.
This pigmentation is of a temporary nature. However, the disease is progressive and may persist for several months or up to a year. In severe cases, several years of continual eruptions could occur. The general health of the patient is usually not impacted upon and the condition often resolves spontaneously.
Acute Varioliform Lichenoid Pityriasis
Occurring more frequently in young people, but it can occur in people of any age.
The lesions mainly appear on the trunk and flexor aspect (creases) of the arms and legs. The mucous membranes of the mouth and genitals can also be affected.
Exposure to light aggravates the condition. The lesions present as pale red or reddish-brown oval/round raised spots or blisters of 2-10mm in diameter. Haemorrhaging of the blisters occurs followed by necrosis of the ruptured tissue. Crusting and scaling follow and the formation of slightly depressed scars result. The presence of varying stages of lesions is characteristic of this condition. The lesions tend to reoccur in “crops” of outbreaks affecting different areas of the body over several weeks or even months. In its most severe form these “crops” of lesions will continue to reoccur over several months or even years.
The patient can also be sensitive to the cold, show signs of fever, lassitude and aching joints.