Milia A milium is a white papule, 1 to 2 mm in size, composed of laminated, keratinous material and situated as a solid cyst in a pilosebaceous follicle. Milia are fairly common on the brow, glabella, and nose in newborn infants and in such infants tend to disappear quickly and spontaneously. There may be few or many, and they may develop later in infancy, in childhood, and in adolescence. In older children and adolescents, they tend to persist, may precede acne or be associated with incipient acne and commonly develop on or around the eyelids. Milia may be ablated, if desirable, by delicate incision and expression of the keratinous content. Lesions that are treated do not recur, but if new lesions appear, they have to be treated in the same way. The operation is trivial and uncomplicated. There are no preventive measures.

Eosinophilic pustular folliculitis of infancy Children with this rare disorder develop repeated crops of pruritic erythematous papules, yellow or white pustules, which vary in size from 1 to 3 mm. Most lesions are located on the scalp and distal extremities. Tzanck smear may reveal numerous eosinophils, and there may also be a peripheral eosinophilia when flaring. Eosinophilic pustular folliculitis is associated with no systemic symptoms and eventually resolves spontaneously. Therapy with topical steroids is beneficial.

Infantile acropustulosis This cutaneous disorder is characterized by recurrent episodes of intensely pruritic pustules and papulovesicles on the hands and feet. Lesions are most common on the palms and soles but may be seen on the dorsal surfaces as well.

Lesions may also occur on the ankles, forearms, and, rarely, the face, scalp, and upper trunk. The age at onset is typically between 2 and 10 months. Individual episodes last for 7 to 10 days and may recur as often as every 2 weeks at the beginning of the disease. Episodes tend to become less frequent and severe over time.

Infantile acropustulosis Stained smears of an individual lesion will reveal numerous neutrophils, although eosinophils may be present early in the course of the disorder. Infantile acropustulosis may also be seen after scabies infestation in infants (“postscabies syndrome”).

Figure 2-7 shows involvement of the forehead in a patient with infantile acropustulosis. The disease resolves spontaneously by 2 to 3 years of age. The individual lesions in this condition may resolve with scale and postinflammatory hyperpigmentation.

Miliaria crystallina The lesions in this condition are small, clear, thin-roofed vesicles that develop when the sweat duct is obstructed within the stratum corneum. They occur after sunburn or in response to excessive sweating in high environmental heat and humidity. Fever may also be a cause.

The scalp, face, trunk, and intertriginous areas are sites of lesions. Itching is not a symptom. The vesicles resolve rapidly with the elimination of the causative environmental factor.

Miliaria rubra (prickly heat) This is the most common form of miliaria. It occurs when there is plugging of the eccrine ducts and release of sweat into the adjacent skin. Miliaria rubra is characterized by discrete erythematous papules and papulovesicles. The forehead, upper trunk, and intertriginous areas are commonly affected. Unlike miliaria crystallina, miliaria rubra is characterized by spasmodic pricking sensations. A decrease in environmental heat and humidity is the only treatment required.

Fox-Fordyce disease (apocrine miliaria) This chronic and intensely pruritic papular eruption is localized to the axillae, areolae, and pubic areas where apocrine glands are found. It occurs almost exclusively in young women, frequently with the onset during adolescence. The follicular papules result from the obstruction of the intraepidermal sweat duct, with the release of apocrine sweat into the surrounding skin.

Figure 2-11 shows the process in an axilla; Fig. 2-12 shows it in the pubic area. The etiology of Fox-Fordyce disease is unknown and the treatment is difficult. Topical retinoids, hormonal therapy, and antimicrobial therapy are sometimes helpful. Pimecrolimus, a topical immunomodulator, has recently been shown to be beneficial.

Neonatal cephalic pustulosis This disorder is characterized by the development of numerous very small erythematous papulopustules over the scalp, face, and neck. Lesions usually develop during the second or third week of life. Researchers believe that this eruption is identical to that which was previously termed as neonatal acne. Recent research suggests that the cause is the lipophilic yeast, Malassezia. M furfur or M sympodialis, can be isolated from the skin of most patients. Topical ketoconazole is a safe and effective treatment.

Neonatal and infantile acne Mild comedonal acne is fairly common in the newborn. The typical eruption consists of closed comedones. Open comedones, inflammatory papules and pustules, and small cysts may also occur. Neonatal acne is due to the stimulation of sebaceous glands by androgens from both mother and infant.