In addition to atopic dermatitis, numerous other endogenous and exogenous dermatoses are seen in prepubertal children including nappy rash, psoriasis, neonatal acne and allergic rashes. Many of these childhood dermatoses will clear over time with environmental modification or no intervention, but some may require treatment.
- Most cases of nappy rash are due to irritation and maceration, but Candida albicans infection, seborrhoeic dermatitis and psoriasis are other common causes.
- Not all babies with seborrhoeic dermatitis recover; one-third will develop psoriasis and another third, atopic dermatitis.
- The early signs of psoriasis in children include cradle cap, nappy rash, and post- and infra-auricular scaling and fissuring.
- Childhood-onset psoriasis, ichthyosis vulgaris and keratosis pilaris are often confused with atopic dermatitis.
- Urticaria is the only childhood skin condition that is effectively treated with antihistamines.
- Hypersensitivity to insect bites and plant contact dermatitis are common in children and preventative measures are often the best treatment.
The earliest dermatoses seen in infants other than atopic dermatitis are nappy rash, seborrhoeic dermatitis and neonatal acne. In preschool-aged children, florid insect bite reactions may be a problem. Skin conditions that are often confused with atopic dermatitis are childhood-onset psoriasis and the keratinisation disorders, ichthyosis vulgaris and keratosis pilaris. The most common allergic skin conditions in children, other than insect bite reactions, are virally induced urticaria and contact allergy to plants.
Nappy rash is the term used to describe any rash occurring in the area under the nappy. It has become less common, probably due to the use of highly absorbent disposable nappies.
A simple irritant dermatitis is the most common cause of nappy rash, but there are many other causes, including Candida albicans infection (Figure 1), seborrhoeic dermatitis and psoriasis (Figure 2). There are also some very rare causes, such as zinc deficiency and Langerhans cell histiocytosis, and thus any infants with a severe, nonresponsive rash, particularly with lesions in areas other than under the nappy, should be referred to a dermatologist. Nappy rash can be mild or it can become so inflammatory that ulceration occurs. Rarely, it may become papular or nodular and result in lesions that can appear alarming. This condition is called pseudoverrucous papules and nodules (PPN).1
Generally, a simple irritant rash does not involve the flexures, whereas endogenous dermatoses and infections do. Irritant nappy rash results from loss of barrier function of the epidermis due to maceration from urine and irritation from faecal enzymes. Sometimes topical products, including soap and over-the-counter treatments, aggravate the rash. In many cases of nappy rash, the affected area is colonised with C. albicans.