Keratosis pilaris is a normal variant. It is difficult to treat effectively and is best ignored. If treatment is desired, keratolytics such as urea, salicylic acid or glycolic acid can be used overnight in combination with an abrasive therapy (e.g. an abrasive sponge or facial scrub) in the shower in the morning. Care should be taken when using these topical preparations in children as they may sting or cause redness, irritation or dryness.
If facial redness is a problem, keratosis pilaris can be treated with vascular laser, although the results are variable. This treatment is uncomfortable and expensive, requiring a general anaesthetic in most children. It may be best, therefore, to wait until patients are old enough to make the decision for treatment themselves. Unless very highly motivated, most patients tire of topical treatment eventually and accept the condition.
Common allergic rashes
The term papular urticaria is used to describe hypersensitivity to insect bites, usually from mosquitoes and fleas. It is a misleading term, as it bears no relation to ordinary urticaria and the condition is not helped by antihistamines.
Seen in young children aged between 2 and 6 years, papular urticaria usually occurs in spring and summer. The lesions most often occur on exposed surfaces (Figure 9), although fleabites usually occur under clothes. Individual lesions are intensely itchy papules, blisters and crusts. Scratching leads to excoriation, infection and ulceration that may result in scarring and hypopigmentation. The prognosis of this condition is good, with most children becoming hyposensitive to the bites after two to four years. In children of any age, grass ticks can also produce very persistent itchy papular rashes.
The best approach in regard to papular urticaria is prevention with insect repellent, protective clothing and insect control, using insecticide, screens and treatment of pets. These strategies must be maintained throughout spring and summer. If infection occurs, it can usually be treated with topical antibiotic ointment and itch can be relieved with topical corticosteroid. It is best to use a potent corticosteroid and to cover the lesions with a dressing to prevent excoriation. In areas where grass ticks occur, avoidance of playing outside is the best prevention.
Urticaria (hives) is most often a benign, self-limiting, condition in children (Figure 10). The most common precipitant is a preceding or current viral illness but foods and medications can be less often involved. Intestinal giardiasis may cause urticaria and, occasionally, urticaria may be a complication of scabies and fungal infections. Extensive systemic investigations are rarely indicated for children with this condition.
The best approach to urticaria management is simply to treat children empirically with an oral nonsedating antihistamine such as cetirizine or loratadine for two weeks or until the rash has resolved, and then gradually withdraw it. If the rash recurs, the antihistamine can be restarted and an attempt made to withdraw it every two weeks. If urticaria persists for more than six weeks, it is worth excluding giardiasis, and an elimination diet may be considered. In children, this is best done with the help of a dietitian with an interest in food allergy.
Antihistamines have been linked to sudden infant death syndrome in children under 2 years of age and should only be used in children younger than 12 months if the rash is very distressing; in this case only a nonsedating preparation should be used.