Elicitation response characteristics to permanent hair dye in paraphenylenediamine-allergic volunteers.

BACKGROUND: Elicitation response characteristics to complete permanent hair dye products in paraphenylenediamine (PPD)-allergic volunteers have not previously been explored in detail. OBJECTIVES: To assess the elicitation response characteristics observed in PPD-allergic volunteers upon patch testing with complete hair dyes. METHODS: PPD-allergic volunteers were assigned to 1 of 3 groups depending upon whether they elicited + (group 1), ++ (group 2) or +++ (group 3) reactions following the standard diagnostic procedure. Each group was subsequently patch tested with 2 complete hair dyes (A and B) for 30 min, 1 hr and 24 hr. Patch sites were examined 1 day, 2 days and 3 days after patch removal. RESULTS: Exposure to either hair dye for 30 min or 1 hr was insufficient to yield positive patch test reactions in all of the PPD-allergic patients in groups 1 or 2. Application of either hair dye for 24 hr was sufficient to yield positive reactions in all of the individuals within groups 2 and 3. CONCLUSIONS: The frequency of positive patch test reactions observed following 24-hr exposure to complete permanent hair dyes is comparable to that observed following 48-hr exposure to 1% PPD/petrolatum in those individuals whose degree of sensitization is such that they typically present ++ or +++ reactions diagnostically.

The impact of exposure variables on the induction of skin sensitization.

Whereas many investigations of the variables associated with the elicitation of allergic contact dermatitis have been undertaken, to the point where we can begin to predict the likelihood of elicitation occurring in a given situation, the same is not true for the induction of skin sensitization. Studies have demonstrated that increasing dose has an impact; in an experimental setting, a number of variables received attention some decades ago. However, in the work reported here, the relative importance of the frequency and the duration of exposure is highlighted. In an investigation using a human repeated insult patch test, it was demonstrated that reduction of the exposure duration from 48 hr to 5 min decreased the rate of sensitization to 1% p-phenylenediamine (PPD) from 54% to 3%. However, in an extended clinical study, it was observed that infrequent but longer duration and higher concentration exposure to PPD was significantly less likely to induce sensitization compared to more frequent, short duration, and lower concentration exposure. Detailed statistical analysis of the results indicated that the most important factor driving the induction of skin sensitization was the number of exposures.

Disseminated Mycobacterium chelonae cutaneous infection: recalcitrant to combined antibiotic therapy.

A 25-year-old Thai housewife had a history of tuberculosis of the lymph nodes for six years that had been successfully treated with a course of anti-TB drugs. She developed several red, circumscribed, infiltrative plaques composed of umbilicated papules and pustules on her face and upper part of the body with cervical lymphadenopathy six months later. A pus smear from the lesion grew acid fast bacilli (AFB). Histopathological examination showed a mixed cell granuloma suggestive of infection. A T cell study showed a low CD4 count, and multi skin tests indicated cutaneous anergy. Culture from a biopsy specimen taken from the skin lesion grew M.chelonae; the cultures from blood, urine, and bone marrow. The lesions were not responsive to an anti TB drug given for 2 months based upon the results of the AFB positive pus smear before the culture and sensitivity reports were obtained. Since then the patient was treated with antibiotics according to the results of the sensitivity tests. A combination of amikacin and clarithromycin was started and hyperthermic therapy was later added with a partial response. Based upon the sensitivity test, kanamycin was introduced but had to be stopped because of ototoxicity. Sparfloxacin was used with an effective result but was discontinued for economic reasons. Finally, clarithromycin in combination with clofazimine and cryotherapy were given for a year before the lesions healed completely. It took a three years duration for the total course of treatment for this patient. She is still in remission after two years of follow-up period. This extensive cutaneous M.chelonae infection needed a prolonged combination of antibiotics with the addition of cryotherapy for the non-responsive lesions.