Topical capsaicin in dermatologic and peripheral pain disorders.

Topical capsaicin has been introduced in the U.S. and Canada as a cream indicated for temporary relief of neuralgia following episodes of herpes zoster infections and in the treatment of diabetic neuropathy. Although capsaicin is clinically used as an external analgesic for temporary relief of neuralgia, it has also been widely used as a research tool to study peripheral pain. Capsaicin apparently works to release substance P from sensory nerve fibers and after repeated applications, depletes neurons of substance P. Clinical investigations of topical capsaicin include trials in chronic pain syndromes such as postherpetic neuralgia, postmastectomy neuroma, reflex sympathetic dystrophy syndrome, diabetic neuropathy, rheumatoid arthritis, psoriasis, hemodialysis-associated itching, and vulvar vestibulitis. In addition, therapeutic benefits of capsaicin cream on apocrine chromhidrosis have been described. Further clinical studies are warranted in several of these conditions to establish the efficacy of topical capsaicin. Serious or unexpected adverse reactions from clinical use have not been reported to date. Considering the paucity of safe and effective treatments for the conditions mentioned above, capsaicin cream appears to warrant further clinical investigations to establish its efficacy in a variety of chronic pain syndromes.

Sunscreens: what you and your patients should know.

The proper use of sunscreens may minimize the effects of sun exposure. This article examines characteristics of ultraviolet radiation, identifies patients most susceptible to harmful sun exposure, and evaluates selected sunscreen products.

Clinical evaluation of an after-pediculicide nit removal system.

A significant problem in the management of pediculosis is the removal of nits from the hair after pediculicide treatment. This study describes use of a nit removal system incorporating a cream rinse containing formic acid that loosens the bond between the nit and hair. Twenty-four children with pediculosis capitis, age 4 to 12 years, were evaluated. Sections of hair with equivalent numbers of nits were identified as control or test sites. Combining for 5 minutes after use of the formic acid rinse removed 93.5% of nits compared with a 27.6% reduction in the control section (p less than 0.0001). These results demonstrate that use of this nit removal system greatly facilitates nit removal.

Stability-time profile of trichloroacetic acid at various concentrations and storage conditions.

Trichloroacetic acid (TCA) is a deliquescent chemical widely used for a variety of procedures. Stability of various concentrations of TCA in both amber glass and plastic bottles stored under refrigeration and at room temperature was measured at several time points. Extended stability data suggest that TCA potency is stable for 23 weeks and would best be maintained in glass amber bottles stored under refrigeration.

Evaluation of oral minoxidil in the treatment of alopecia areata.

A dose-response effect has previously been demonstrated in topical minoxidil treatment of alopecia areata. Limitations in minoxidil solubility and percutaneous absorption have impaired the development of more effective topical therapy. Oral minoxidil (5 mg every 12 hours), a dose demonstrated to be relatively well tolerated if a 2-g sodium diet is strictly followed, was given to 65 patients with severe, treatment-resistant alopecia areata in an attempt to bypass the limitations of topical treatment and increase efficacy. Although hair regrowth progressed more rapidly and was more extensive with oral than topical 5% minoxidil, cosmetic response was seen only in 18% of the patients. Neither serum nor tissue levels of minoxidil correlated with response. These findings suggest that improved preparations of topical minoxidil, when used as a single therapeutic agent, are unlikely to be cosmetically effective in the majority of patients with severe alopecia areata.

Topical minoxidil therapy for hair regrowth.

The pathogenesis of hair loss, the postulated mechanisms of minoxidil action on hair growth, and clinical trials, adverse reactions, experimental formulations, and percutaneous absorption of topical minoxidil preparations are reviewed. Topical minoxidil seems to normalize hair follicles and increase blood flow to the scalp. In clinical trials of various formulations, results have varied. Improved hair growth occurred after four to six months of therapy; twice-daily application seems to be indicated. The most frequently reported adverse reactions are mild scalp dryness and irritation and, rarely, allergic contact dermatitis. Current recommendations are to reserve topical minoxidil for patients with normal cardiovascular status and to routinely monitor blood pressure, heart rate, and electrocardiographic changes. A new drug application is pending with FDA for use of topical minoxidil in androgenetic alopecia (male-pattern baldness), which is genetically determined and apparently stimulated by androgens. For alopecia areata, which involves hair loss on the body or scalp, usually patchy and of sudden onset, no reliable treatment has been found, although minoxidil may be efficacious in some patients. Minoxidil has generated new interest in hair-loss research. The etiology of hair loss must be better understood before more effective treatment regimens can be designed.

Evaluation of topical metronidazole gel in acne rosacea.

Topical metronidazole gel (0.75%) was compared to placebo gel in a randomized, double-blind, placebo-controlled, split-face clinical trial for the treatment of 59 patients with acne rosacea. Statistically significant differences in inflammatory lesions, erythema, and global assessments were seen at three, six, and nine weeks post-baseline in favor of the active treatment side. It did not, however, alter the telangiectatic component of the disease. No known drug-related side effects were detected, and the low topical dose along with low serum levels of metronidazole indicate a high safety profile for this therapeutic agent. This work suggests that metronidazole gel, as specifically formulated, is safe and effective in reducing the symptomatology of acne rosacea.

Topical mupirocin in the treatment of bacterial skin infections.

Mupirocin is an investigational topical antibiotic used for treatment and prophylaxis of bacterial skin infections. Mupirocin differs from other antibiotics in its synthesis, structure, and mechanism of action. In vitro, mupirocin possesses antimicrobial activity against staphylococci, streptococci, Hemophilus influenzae, and Neisseria gonorrhoeae. Few studies comparing mupirocin to other topical antibiotics are available. Initial studies comparing mupirocin to inactive vehicle in the treatment of impetigo indicate an overall 92 percent pathogen eradication rate with active drug and 58 percent eradication rate with vehicle. Overall response to treatment of secondary skin infections was favorable in 91 percent of patients treated with mupirocin and 77 percent of those treated with vehicle. Although incidence is not greater than placebo, adverse effects have included pruritus, burning, dry skin, and erythema. Additional trials and clinical use should further help determine the role of mupirocin in the treatment of minor, primary, and secondary skin infections.

Topical minoxidil dose-response effect in alopecia areata.

Topical 5% minoxidil solution was used to treat 47 patients with severe alopecia areata. Forty patients (85%) had terminal hair regrowth after 48 to 60 weeks of treatment. In the majority of patients, hair regrowth was not cosmetically acceptable. Data were compared with those from a previous study with topical 1% minoxidil solution. Both the percentage of responders and the quality of their hair regrowth were significantly greater with 5% than with 1% topical minoxidil solution. One patient developed an allergic contact dermatitis to minoxidil, but no systemic side effects were detected. The results strongly suggest a dose-response effect for topical minoxidil treatment of alopecia areata and the importance of exploring modifications in dosing and delivery systems to enhance therapeutic efficacy.

Isotretinoin in severe, recalcitrant cystic acne: a review.

Isotretinoin, an isomer of retinoic acid, recently has been approved by the Food and Drug Administration for treatment of severe, recalcitrant acne. The most impressive effects include inhibition of sebum production and a reversible decrease in sebaceous gland size. Isotretinoin has proved to be an effective drug; response to therapy has been seen in virtually 100 percent of patients treated. Almost all patients experience reversible cutaneous and mucous-membrane symptoms while on isotretinoin treatment. Other common side effects include conjunctivitis (38 percent) and eye irritation (50 percent). The recommended dosage is 1-2 mg/kg/d for no longer than 16 weeks. Isotretinoin is currently the treatment of choice for severe, recalcitrant acne; however, because of potential side effects associated with retinoids, isotretinoin should be reserved for those patients who are unresponsive to conventional therapy, including topical and systemic antibiotics.