REASSURE, MOISTURISE, PROTECT FROM THE SUN (RECOGNITION & ADVICE)
Pityriasis Alba - StatPearls (NCBI Bookshelf NBK431061) - https://www.ncbi.nlm.nih.gov/books/NBK431061/
The consultation is almost entirely about the diagnosis: the family have come because they are frightened of vitiligo or of a fungus. Naming it, saying how long it takes, and stopping the sun from making it more obvious is the treatment. A low-potency steroid is offered below for the itchy or inflamed patch only.
- WHAT IT IS AND WHO GETS IT - a common, harmless skin condition, mostly of children and adolescents, and usually regarded as a small expression of atopic dermatitis; most of these patients have atopy in the background. Ask about eczema, asthma and hay fever - the child's own history, or the family's, may carry atopic dermatitis, allergic rhinitis or asthma.
- WHAT IT LOOKS LIKE - on examination there are several round or oval pale macules or patches - sometimes thin papules and plaques - whose edges fade rather than stop. There may be a little redness, or some scale. Count is usually 4 to 20, size between 0.5 and 5 cm, and they sit mainly on the face, the neck, the upper arms and the upper trunk. Indistinct edges are the point; sharp edges are not this.
- WHY IT GETS WORSE IN SUMMER - the pale areas stand out more once the sun is on the skin, because the skin around them darkens through spring and summer; and they show up more in darker skin. The patch is not spreading; the skin around it is tanning.
- IT IS NOT VITILIGO, AND HERE IS HOW TO SHOW THAT - under a Wood's lamp the patches of pityriasis alba may stand out more, but they do not fluoresce. Vitiligo does - brighter, and with edges that stop sharply. Vitiligo also takes the pigment away completely, and it favours the skin around the eyes and the mouth.
- IT IS NOT TINEA EITHER, AND THE TEST IS CHEAP - scrape the skin, put it in potassium hydroxide, and no fungal element appears. That is what separates it from tinea versicolor and tinea corporis, where fungal elements do show. Do not put a child on an antifungal for months on a guess.
- ASK WHAT HAS ALREADY BEEN PUT ON IT - it matters to ask whether a potent topical steroid has been used before, because that itself can leave the skin pale. Other creams can set off an irritant or an allergic contact dermatitis, and the pigment loss follows the inflammation. In Cairo a strong steroid has often been bought over the counter before the visit, and it can be the cause of the white patch rather than the cure.
- THE TIMELINE IS THE HARDEST PART OF THE CONVERSATION - reassure the child and the parents that this is harmless and that it settles by itself. But be straight with them too: clearing is gradual, and it can run for months, occasionally a few years, though most clear inside 1 year. Say the number out loud or the family will doctor-shop.
- SUN PROTECTION IS ACTIVE TREATMENT HERE - keep the affected skin out of the sun, so the surrounding skin does not darken and make the patches look worse. Sunscreen helps: it stops the patches burning and holds back the darkening around them. Advise them to avoid the sun and to cover up - a wide-brimmed hat, long sleeves - since ultraviolet light makes the scaling worse.
- MOISTURISER DOES THE REST - a mild emollient, petroleum jelly or a simple cream, brings the scaling down. This is the part the family can do daily and see working.
- WHEN IT IS NOT PITYRIASIS ALBA - the article flags persistence and change: mycosis fungoides comes into the frame where lesions persist, cause symptoms, and go on altering in shape or in colour. It also lists the ash-leaf macules of tuberous sclerosis, and it names leprosy among the differentials. A hypopigmented patch that is numb, or one child with several plus seizures or developmental delay, is not a reassurance visit.