Tacrolimus: the drug for the turn of the millennium?

BACKGROUND: Tacrolimus has been shown to be a powerful suppressor of the immune system. It was introduced into clinical use to prevent allograft rejection and is now routinely used in kidney, liver, and heart transplantation. Recently, 2 double-blind multicenter studies demonstrated the therapeutic efficacy of topical and systemic tacrolimus in the inflammatory skin diseases atopic dermatitis and psoriasis. DATA SOURCE: MEDLINE was searched for relevant publications and combined with our own clinical, in vitro, and in vivo studies. STUDY SELECTION: All studies dealing with tacrolimus and dermatology were reviewed. DATA EXTRACTION: Publications with clinically relevant data were included in this review. CONCLUSIONS: Topical tacrolimus is a safe and effective therapeutic agent that may open a new era in the treatment of inflammatory skin diseases, particularly for patients with atopic dermatitis. Before its full potential in dermatology can be assessed, more clinical experience in treating children and comparison with the criterion standard of anti-inflammatory therapy, glucocorticosteroids, are needed.     

Managing the very young patient: a conflict between the requirements of the Children Act and the VD regulations?

We describe the case of a 12 year old girl who presented requesting screening for sexually transmitted infections and discuss a conflict between concerns of clinicians to maintain confidentiality and concerns of social workers to investigate the possibility of sexual abuse.     

Are pruritus and scratching the cough of the skin?

Pruritus is not the equivalent of the cough of the skin, but itch and scratch can certainly be defined as such. In physiological conditions, they share the same function: to exclude a foreign body. Itch/scratching and cough could be selective responses for the same diseases, mainly atopic diseases, and their pathophysiology is similar (role of C fibers and mast cells; role of histamine, substance P and tachykinins). This is an intriguing analogy rather than a pathophysiological identity. It may be inappropriate for many disease settings. Itch and cough can be triggered or enhanced by stress. This similarity is very interesting because it could give rise to many new research ideas.     

Why is hair curly?—Deductions from the structure and the biomechanics of the mature hair shaft

The final shape of a head hair is predetermined through a variety of factors during its formation in the follicle. These are genetic pathways, specific growth factors, cell differentiation and segregation, etc, with spatial as well as chronological dynamics. The cortex of hair consists of two major cell groups. These are characterized by parallel (para-type) or roughly helical arrangements (ortho-type) of the intermediate filaments (IF). There are also cell-specific differences in the disulphide content, that is, of the cross-link density of the IF-associated matrix proteins. Given the current state of the academic discussion, we consider it as timely to support and broaden the view that, the structural differences of the cell types together with their lateral segregation are the main driving factor of curl formation. The mechanical effects, which derive thereof, are triggered in the transition zone of the follicle, that is, upon formation of the mature hair shaft. Furthermore, an irregular, “flat” cross section of the hair shaft is shown to be a synergistic but not determining factor of curl formation. The degree of cell type segregation along the mature hair shaft together with dynamic changes of the location of the plane of segregation, namely in a non-circular cross section can account for very complex curl patterns. Against the background of these views, we argue that contributions to hair curl are implausible, if they relate to physical mechanisms which are active below the transition zone from the living to the mature (dead) hair.     

Psoriasis and the pregnant woman: what are the key considerations?

Pregnancy is characterized by multiple physiologic changes. During the entire gestational period, both mother and infant are vulnerable to a variety of external and internal factors. Maternal disease, use of certain medications, drugs, alcohol, smoking, and radiation exposure can have devastating effects on the fetus. Pregnancy-related complications in women with psoriasis can be caused by both the disease and the treatment. The response of the maternal placenta to psoriasis-induced inflammation and comorbid conditions, such as obesity, hypertension, and depression, may also influence the pregnancy. Herein, we review the relationship between psoriasis and undesirable pregnancy outcomes.     

Can increasing the viscosity of formulations be used to reduce the human skin penetration of the sunscreen oxybenzone?

The effect of adding thickening agents on the penetration of a sunscreen benzophenone-3 through epidermal and a high-density polyethylene membrane was studied using both very thick (infinite dose) and thin (in use) applications. Contradictory results were obtained. Thickening agents retard skin penetration, in a manner consistent with a diffusional resistance in the formulation, when applied as an infinite dose. In contrast, when applied as in thin (in use) doses, thickening agents promote penetration, most likely through greater stratum corneum diffusivity arising from an enhanced hydration by the thicker formulations. The two key implications from this work are (i) a recognition of the danger in the potential extrapolation of infinite dosing to in use situations, and (ii) to recognize that thicker formulations may sometimes enhance the penetration of other topical agents when applied "in use".