Milker's nodule: an occupational infection and threat to the immunocompromised.

Milker's nodule virus, also called paravaccinia virus, is a DNA virus of the parapoxvirus genus transmitted from infected cows to humans. It results from contact with cattle, cattle by-products or fomites. Classified as an occupational disorder, those at risk of exposure include farmers, butchers and agricultural tourists. The viral infection begins 5-15 days after inoculation as an erythematous-purple, round nodule with a clear depressed centre and a surrounding erythematous ring. While familiar to those in farming communities, the presence of the nodule may be concerning to others, particularly the immunosuppressed. Milker's nodules are self-limited in immunocompetent individuals and heal without scarring within 8 weeks. Another member of the Parapoxvirus genus, the orf virus, is also transmitted from animals to humans by direct contact. While complications are rare, haematopoietic stem cell transplant recipients are at risk of graft-versus-host disease, as the parapoxvirus may trigger these complications in immunocompromised individuals. In addition, paravaccinia may serve as the antigen source for the development of erythema multiforme. The unique structure and replication process of viruses in the Poxvirus family, while includes the Parapoxvirus genus, have been a focus for treatment of infections and cancer. Manipulation of these viruses has demonstrated promising therapeutic possibilities as vectors for vaccines and oncologic therapy.

Vitiligo: recent insights and new therapeutic approaches.

Vitiligo represents a selective destruction of the melanocytes. It is a relatively common, probably autoimmune disorder that affects people of all backgrounds and both genders. No particular group seems to be preferentially affected. Half of vitiligo patients have an onset before the age of 18 years. In regions where leprosy is endemic, individuals with vitiligo are often stigmatized due to similarities in appearance between the two diseases. We will review this important subject, emphasizing the latest therapeutic advances.

Pediculus humanus capitis: an update.

Head lice infestation, or pediculosis capitis, caused by Pediculus humanus capitis, is a common health concern. In the US, where pediculosis capitis is the most prevalent parasitic infestation of children, 6 to 12 million people are affected every year. Pediculosis capitis remains confined to the scalp. Scalp pruritus is the cardinal symptom, although patients with lice can be asymptomatic. Pruritus with impetiginization should prompt the physician to look for lice or viable nits. All close contacts should be examined. Treatment directed at killing the lice and the ova should be considered only if active lice or viable eggs are observed. The three fundamental effective treatment options for head lice are topical pediculicides, wet combing, and oral therapy. Spraying or fogging a home with insecticides or pediculicides is not recommended.

Oculocutaneous albinism.

Oculocutaneous albinism represents a group of inherited skin disorders characterized by a generalized reduction of cutaneous, ocular and pilar pigmentation from the time of birth. Oculocutaneous albinism types 1 and 2 are the most common, but several other types have been described. A defect in the melanin synthesis pathway, resulting in reduced formation of melanin, is responsible for oculocutaneous albinism. Aetiology, clinical manifestations, diagnosis and management are discussed.

Childhood herpes zoster.

Herpes zoster (HZ) in childhood is rather unusual. This reactivation of chickenpox, the primary varicella-zoster virus (VZV) infection that lies dormant within sensory ganglia, is seen with increased frequency in otherwise healthy children who acquire chickenpox either in utero or within the first year of life. Our patient is a good example of this; he was exposed to chickenpox at the age of 3 months (by his 2 siblings) and developed HZ at 6 years of age.

Usefulness of diagnostic criteria of tuberous sclerosis complex in pediatric patients.

The Tuberous Sclerosis Complex 1998 Consensus Conference clinical criteria represent an important advance in the diagnosis of tuberous sclerosis complex. Since many findings regarded as highly specific for tuberous sclerosis complex are not apparent until late childhood or adulthood, refinements by age may prove of value. We have stratified 106 children into five age groups (0 to 2 years of age, above 2 to 5 years, above 5 to 9 years, above 9 to 14 years, and above 14 to 18 years). Physicians should be alerted as to the frequency of the criteria in different stages of children.

Acrodermatitis enteropathica-like eruption in an infant with nonketotic hyperglycinemia.

Acrodermatitis enteropathica is a rare inherited disorder characterized by zinc deficiency and a triad of dermatitis, diarrhea, and alopecia. It is an autosomal recessive condition thought to be due to the inability to absorb zinc from the gastrointestinal tract. Acquired zinc deficiency due to a variety of etiologies may produce a similar clinical picture. These causes include inadequate supply, malabsorption, and low zinc stores. In addition to zinc, deficiencies of other nutrients such as branched chain amino acids have induced an acrodermatitis enteropathica-like eruption. We describe a case of a 26-month-old boy with a rare inborn error of metabolism known as nonketotic hyperglycinemia who developed an acrodermatitis enteropathica-like eruption. In addition to zinc deficiency, the patient was deficient in branched chain amino acids due to a low protein diet instituted to reduce his elevated glycine levels. The rash did not respond to zinc replacement alone, and therefore is most likely a combination of amino acid and zinc deficiency. Acrodermatitis enteropathica-like eruptions have been described in other conditions that cause decreased serum amino acids, such as maple syrup urine disease and organic acidurias. This is the first case describing an association between acrodermatitis enteropathica and nonketotic hyperglycinemia.

Tinea capitis: current concepts.

Tinea capitis is an important fungal infection that may at times be a clinical, diagnostic and therapeutic challenge. It is common in childhood around the world, becoming almost epidemic in some communities. The central European and American experience with it is somewhat variable, due to different etiologic fungi. The use of topical antifungal agents and other approaches is stressed as of value alongside the use of systemic antifungal medication.

Alopecia areata. Pathogenesis, diagnosis, and therapy.

Alopecia areata is a common form of non-scarring alopecia that appears equally in males and females of any age, although children and adolescents are more commonly affected. The disorder is usually characterized by limited alopecic patches on the scalp, but more severe forms may affect the entire scalp (alopecia totalis) or body (alopecia universalis). Characteristic nail changes may also accompany hair loss. Alopecia areata has been linked with certain human leukocyte antigen (HLA) class II alleles, indicating a probable autoimmune etiology. Current research implicates T lymphocytes in the pathogenetic mechanism of disease. Other autoimmune diseases are also linked with alopecia areata. The diagnosis of alopecia areata is usually made clinically, although a biopsy is diagnostic for this condition. Treatment is challenging and aims at the regrowth of hair in affected individuals. Intralesional corticosteroid injections are widely used in mild disease. Topical anthralin and minoxidil may also be clinically efficacious. Topical sensitizers, such as squaric acid dibutlyester and diphenyl-cyclopropenone, are sometimes employed. Various therapies for the disease may have efficacy in different patients, making a universal treatment algorithm difficult to implement. Patients should be handled on an individual basis, with the final outcome based on the cosmetic regrowth of hair. Maintenance therapy is also important in patients that do achieve acceptable regrowth, necessitating a highly motivated patient and good rapport with the treating physician.

Cutaneous signs of selected systemic diseases.

In this work we will discuss three cutaneous markers of systemic disease. Acanthosis nigricans is the most widely known in this category. Cutaneous angiokeratomas are usually associated with enzyme defect disorders, such as Fabry's disease, and are linked in this work as a reactive pattern in hepatorenal failure. Mast cell disease may occur in a number of forms, often with systemic involvement.