Vascular malformations. These are congenital malformations that consist of capillary, venous, arterial, or lymphatic abnormalities. There are often combined alformations that comprise different types of vessels. Examples of vascular malformations include port-wine stains (capillary malformation), cystic hygroma (lymphatic malformation), and venous malformations. Vascular malformations are present at birth and grow proportionately with the child. Some vascular malformations may not manifest themselves until adolescence or adulthood. These figures represent venous malformations on the hand and foot.
Erythema infectiosum (fifth disease). Erythema infectiosum is a mild childhood disease that is caused by human parvovirus B19. This condition develops after a mean incubation period of 14 days. There are few if any prodromal symptoms. The rash evolves in three clinical stages. The first stage is characterized by the abrupt appearance of a bright-red malar blush. The appearance is so startling that it has been given the suggestive description of “slapped cheeks”. During the second stage, the facial rash begins to fade, and a maculopapular, urticarial, or morbilliform exanthem develops on the extremities and trunk. Pruritus may be present.
Allergic contact dermatitis (reaction to temporary tattoo). Contact allergy to temporary tattoos has become an increasingly common phenomenon. In most cases, the tattoo material does not contain pure henna, but is a mixture of brown henna with paraphenylenediamine (PPD) called black henna. The patient is allergic to PPD in the tatto. In fact, the concentration of PPD in black henna is higher than that seen in commercial hair dyes. After resolution of the eczematous skin eruption, postinflammatory hyperpigmentation may persist for a considerable period of time.
Hand-foot-and-mouth disease. Multiple, superficial erosions and small, vesicular lesions surrounded by an erythematous halo on the lower labial mucosa; the gingiva is normal. In primary herpetic gingivostomatitis, which presents with similar oral vesicular lesions, a painful gingivitis usually occurs as well.