Photoallergic contact dermatitis is uncommon

BACKGROUND

Despite the enormous increase in sunscreen use, allergic contact (AC) and photoallergic (PA) reactions to ultraviolet (UV) filters are considered rare.

OBJECTIVES

To analyse the data from 2715 patients who underwent photopatch testing at St John's Institute of Dermatology during the period 1983-98.

METHODS

A retrospective analysis of all positive photopatch test episodes was undertaken with the results retrieved from the environmental dermatology database and further verified with the original archived patch test documentation for each individual patient.

RESULTS

In 111 patients with positive reactions (4.1%), there were 155 AC or PA reactions to allergens in the photopatch test series. Eighty PA reactions were observed in 62 (2.3%) patients (32 men and 30 women, age range 28-75 years), with UV filters accounting for 52 positive reactions (65%), drugs 16 (20%), musk ambrette 11 (14%) and the antiseptic trichlorocarbanilide one (1%). The most common UV filter photoallergen was benzophenone-3 with 14 positive results, followed by benzophenone-10 (n = 9), isopropyl dibenzoylmethane (n = 6), p-aminobenzoic acid (PABA) (n = 5), octyl dimethyl PABA (n = 5), butyl methoxydibenzoylmethane (n = 4), isoamyl methoxycinnamate (n = 2), ethyl methoxycinnamate (n = 2), octyl methoxycinnamate (n = 2), amyl dimethyl PABA (n = 2) and phenylbenzimidazole sulphonic acid (n = 1). A similar number of AC reactions to UV filters was detected in this study. Thus 49 patients (1.8%) had a total of 75 reactions: 51 due to UV filters and 24 as a result of exposure to fragrances and therapeutic agents. Benzophenone-10 accounted for 13 AC reactions and benzophenone-3 for eight reactions. Twenty-two patients had a PA reaction alone, whereas 19 patients had chronic actinic dermatitis and 15 patients polymorphic light eruption (PLE) in addition. Thus, 34 of the 62 patients (55%) had a preceding underlying photodermatosis.

CONCLUSIONS

These results show a low yield of positive photopatch tests. Thus, despite the large increase in the use of UV filters over the last decade, the development of PA reactions remains rare. Furthermore, most of the common UV filter photoallergens identified in this study, including PABA, amyl dimethyl PABA and benzophenone-10, are now rarely used in sunscreen manufacture, while isopropyl dibenzoylmethane was voluntarily removed from the market in 1993. Currently, benzophenone-3 is the commonest contact photoallergen still in widespread use. In contrast, the UVB filter octyl methoxycinnamate, used in a number of sunscreens, produced only two positive PA reactions in 12 years of testing. Nevertheless, although these reactions are extremely rare, patients with photodermatoses such as PLE and chronic actinic dermatitis do represent a group of patients at increased risk of developing photoallergy. Further photopatch test series should be regularly reviewed and updated, as the relevance of individual photoallergens changes over time. Currently, there is no evidence that PA reactions represent a common clinical problem.

A retrospective analysis of contact allergy to lanolin

BACKGROUND

Lanolin is often stated to be an important sensitizer but some of the available literature is based on the analysis of high-risk patients.

OBJECTIVES

To analyse the frequency of contact allergy to lanolin (wool alcohols) in a central London teaching hospital patch-test population.

METHODS

Review of 24,449 patients recorded on our database during 1982--96 who were tested with a standard series containing 30% wool alcohols.

RESULTS

The mean annual rate of sensitivity to this allergen was 1.7%. The wool alcohols-allergic group contained a higher proportion of females (P < 0.05), and the mean age of both males and females (48.4 and 49.2 years) was higher than that of non-wool alcohols-allergic patients (41.4 and 35.9 years; P < 0.0005). There was no difference in atopic eczema status between these groups. The highest prevalence of allergy to wool alcohols was among patients with lower leg dermatitis (6.0%; 95% confidence interval, CI 4.46--7.54), followed by those with anogenital dermatitis (3.23%; 95% CI 1.81--4.65). There was an unexplained decline in the rate of positive patch tests to Amerchol L-101. However, some patients who reacted to this were negative with wool alcohols, so it may be a useful additional test reagent. The mean rates of allergy to Eucerin (0.65% per annum) and 50% hydrogenated lanolin in petrolatum (1% per annum) were low, and we no longer use these as test reagents.

CONCLUSIONS

This study illustrates that lanolin sensitization has remained at a relatively low and constant rate even in a high-risk population (i.e. patients with recent or active eczema).

Changing frequency of thiuram allergy in healthcare workers with hand dermatitis

BACKGROUND

Healthcare workers (clinical, allied/paramedical professions and ancillary workers) may have prolonged contact with natural rubber latex devices, particularly in the form of natural rubber latex gloves.

OBJECTIVES

To examine the changing frequency of type IV thiuram allergy in healthcare workers with hand dermatitis over a 16-year period.

METHODS

During the study period, 450 healthcare workers (352 women and 98 men) with hand dermatitis were investigated, and their patch test results were analysed retrospectively.

RESULTS

On average, a thiuram-positive patch test was noted in 12% of individuals, with a peak incidence of 27% of the patients patch tested in 1994. Comparison of results between 1983--88 and 1989--93 showed a statistically significant increase in the incidence of thiuram-positive patch tests (odds ratio 2.55, 95% confidence interval 1.25--5.20, P = 0.01).

CONCLUSIONS

We have documented a changing frequency of thiuram-positive patch tests in healthcare workers with hand dermatitis since 1983. This may reflect changes in degree of exposure to thiurams in medical gloves during this period.

Use of the local lymph node assay for the estimation of relative contact allergenic potency

The effective toxicological evaluation of skin sensitization demands that potential contact allergens are identified and that the likely risks of sensitization among exposed populations assessed. By definition, chemicals which possess the toxicological property of skin sensitization potentially are capable of causing allergic contact dermatitis (ACD) in humans. However, this hazard is not an all-or-none phenomenon; clear dose-response relationships can be discerned and thresholds identified for both the induction of sensitization and the elicitation of contact dermatitis. Commonly, these parameters are grouped under the heading of potency, determination of which is vital for risk assessment. In the present investigation, the local lymph node assay (LLNA) has been employed to determine the relative potency of a range of 20 chemicals. The parameter used is the estimated concentration required to produce a 3-fold increase in draining lymph-node cell proliferative activity, the EC3 value. These measurements have been compared with an assessment of the human sensitizing potency of the 20 selected chemicals, each being assigned to 1 of 5 classes based on their human sensitizing potency. The EC3 value, derived from LLNA work carried out in acetone/ olive oil vehicle, correlated well with the human classification, with the strongest sensitizers having low EC3 values (<O.1%), weaker sensitizers having EC3 values generally in the 1-10% range, and non-sensitizing chemicals having EC3 values in excess of 100%. In conclusion, the derivation of the EC3 for a chemical provides an objective and quantitative estimate of potency that is of considerable utility for skin sensitization risk assessment.

How do you manage dermatitis after exposure to the causative agent has ceased?

Contact dermatitis may not clear completely when the cause of the problem is removed, and in some cases continues long after the causal occupation has been given up. This paper outlines some methods of managing the problem.

Descriptive epidemiology of hand dermatitis at the St John's contact dermatitis clinic 1983-97

For 15 years, hand dermatitis accounted for a quarter of patients seen in this clinic. The highest proportion occurred in women aged 17-30 years. Overall, the male to female ratio was 0.8, which contrasts with population-based studies. Catering was most frequently associated with occupational hand dermatitis. Other frequent occupational associations included metalworking, hairdressing, healthcare and mechanical work.

The frequency of fragrance allergy in a patch-test population over a 17-year period

Fragrances are widely encountered in our daily environment and are known to be a common cause of allergic contact dermatitis. We have reviewed our patch test data from 1980 to 1996 to establish whether the pattern of fragrance allergy has changed with time. During this period, 25,545 patients (10,450 male, 15,005 female) were patch tested with the European standard series. The mean annual frequency of positive reactions to the fragrance mix was 8.5% in females (range 6.1-10.9) and 6.7% in males (range 5.1-12.9). Females were 1.3 times more likely to be allergic to fragrance (P < 0.001, 95% confidence interval, CI 1.17-1.41). Males with fragrance allergy were older than females by 5.6 years (mean age 48.2 vs. 42.6 years; P < 0.001, 95% CI 3.9-7.3). The incidence of a concomitant positive patch test to balsam of Peru in fragrance-sensitive patients showed wide variation, suggesting that it is not a reliable marker of fragrance allergy. There was a positive correlation between the isomers isoeugenol and eugenol. Oak moss remained the most common overall allergen throughout the study, positive in 38.3% of females and 35.6% of males who were tested to the constituents of the fragrance mix. During the period of the study the incidence of positive tests to oak moss increased by 5% yearly (P = 0.001, 95% CI 2.2-8.7). The frequency of allergic reactions to eugenol and geraniol remained relatively constant. Isoeugenol and alpha-amyl cinnamic aldehyde sensitivity increased and hydroxycitronellal showed a slow decline. There was a striking reduction in the frequency of sensitivity to cinnamic aldehyde (by 18% yearly; P < 0.001, 95% CI 14.3-21.0) and cinnamic alcohol (by 9% yearly; P < 0.001, 95% CI 5.2-12.9); these are now uncommon fragrance allergens. These data show temporal trends which may reflect the frequency of population exposure to individual fragrances.

Patch testing with corticosteroid mixes in Europe. A multicentre study of the EECDRG

This study investigated whether a corticosteroid mix containing tixocortol pivalate, budesonide, and hydrocortisone-17-butyrate could detect contact allergy to corticosteroids. 2 corticosteroid mixes, 1 with a high (mix I) and 1 with a low (mix II) concentration and the 3 individual constituents, each at 2 concentrations, were inserted into the standard series of 16 participating clinics. Tests were read on day (D) 3 or 4. 5432 patients were tested, and 110 (2.0%) had positive reactions to at least 1 of the 8 test preparations. Of the 8 preparations, mix I identified most allergic patients, followed by mix II, budesonide 0.10%, budesonide 0.002%, and tixocortol pivalate, both concentrations (1.0 and 0.10%) tracing the same number. With the mixes, 53.2-59.6% of tixocortol pivalate allergy was missed. 47 patients were allergic to either concentration of tixocortol pivalate, 25% of these only to 1.0% and another 25% only to 0.10%. Testing with mix I and tixocortol pivalate 0.10% picked up 98/110, testing with tixocortol pivalate 1.0% and 0.10% and budesonide 0.10% picked up 105/110. 3379 patients were read on both D3 or D4 as well as on D7. Without a late reading (D7), up to 30% of contact allergy to corticosteroid markers was missed.

Patch testing with natural rubber latex

Immediate-type hypersensitivity to natural rubber latex (NRL) may be associated with chronic eczema, and it has recently been suggested that NRL should be used as a patch-test allergen. However, a standardized preparation does not exist, and experience of patch testing with this substance is extremely limited. The aims of our study were to investigate the patch-test response to different preparations of NRL amongst patients with suspected contact dermatitis. 608 patients were patch tested with a latex series which included wet and dry preparations of undiluted high-ammonia (HA) NRL and low-ammonia thiuram-containing NRL. Cutaneous reactions to 1 or more NRL patches were noted in 24 patients. None of these were strong allergic reactions (> +), and in 15 patients, the responses were only doubtful (?+). Positive patch tests were observed in 9 patients, and were probably due to concurrent thiuram allergy in 6. In the remaining 3 patients, the reactions had subsided by the 2nd reading and may have represented false positives. None of the patients showed consistent allergic reactions to all NRL patches, and most of the doubtful readings had resolved within 4 days, suggesting that they were irritant rather than weak allergic responses. Patch testing to dry HA latex was associated with the least number of reactions. We conclude that allergic patch test reactions to NRL are uncommon, and as reactions are usually weak and difficult to interpret, we suggest that patch testing with NRL should remain experimental until further studies have been undertaken.

Contact sensitivity to chromate: comparison at a London contact dermatitis clinic over a 10-year period

It has been argued that for chromate sensitivity to be reduced, then ferrous sulfate should be added to cement. This has not yet been done in the UK. To explore this further, we have looked at the comparative sensitization rates of patients attending the St. John's Institute of Dermatology Contact Dermatitis Clinic between the years 1982-3 and 1992-3. Patch-test-positive rates for females were not significantly different between the 2 populations studied (1982-3, 1.59% and 1992-3, 1.99% p NS). Similarly, there was no significantly different rate between the males (1982-3, 3.99% and 1992-3, 4.25% p NS) in the same time period. There was no difference in the distribution of eczema in chromate-positive subjects, nor of cobalt co-sensitization, a crude indicator of sensitization via cement. This work demonstrates no appreciable difference in the frequency of chromate sensitivity between the early 1980s and 1990s in London. Adding ferrous sulfate to cement may help to lower the frequency in the future.

Pemphigus vulgaris following a hyperimmune response to typhoid booster

We report the case of a 46-year-old Indian woman who developed a hyperimmune response to a typhoid booster injection in association with the development of pemphigus vulgaris. To our knowledge, this association has not previously been reported.

Clinical assessment in the workplace: dermatitis

The clinical assessment of dermatitis in the workplace is put forward as a series of four decisions: (1) is it dermatitis and not psoriasis, tinea, scabies, etc? (2) Is it contact dermatitis and not atopic, seborrhoeic, discoid, stasis or unclassified eczema? (3) Is it irritant contact dermatitis or allergic contact dermatitis? (4) What is/are the probable cause(s)?

Recurrent focal palmar peeling

Recurrent focal palmar peeling, previously known as keratolysis exfoliativa, is an idiopathic condition characterized by chronic palmar and occasionally plantar peeling. It can be exacerbated by environmental factors, and may be misdiagnosed as chronic contact dermatitis. Accurate diagnosis is from the history and examination. It is supported by a negative patch test result. Three cases of recurrent focal palmar peeling are presented, of which two were misdiagnosed as chronic dermatitis. Although there are few references on recurrent focal palmar peeling, it is likely to be a common condition that rarely presents to dermatologists because it is largely asymptomatic. A correct diagnosis is essential due to the social, occupational and legal implications if misdiagnosed.

Variation in response of human skin to irritant challenge

A major obstacle to the establishment of a protocol for in vivo irritant skin testing in humans is the apparent variability of responses between individuals. This study of the threshold response of normal human skin to a standard irritant (sodium lauryl sulfate 0.3-10%), in a group of 22 subjects, revealed a marked interindividual variation in their threshold reaction. The results demonstrate that this phenomenon does exist and that it will have to be allowed for in future human irritant test systems or assays.

Patch testing with preservatives at St John's from 1982 to 1993

We have reviewed our patch test results for preservative allergy from 1982 to 1993. 8 preservatives were included: formaldehyde, 2-bromo-2-nitropropane-1,3-diol (Bronopol(TM)), quaternium-15 (Dowicil 200TM), imidazolidinyl urea (Germall 115TM), diazolidinyl urea (Germall IITM), parabens, 5-chloro-2methyl-isothiazolin-3-one (Kathon CG(TM)) and 1,2-dibromo-2,4-dicyanobutane (one of the constituents of Euxyl K 400TM). Whereas the allergy rate to formaldehyde is quite stable, there is a slight increase in the imidazolidinyl urea allergy rate. Quaternium-15's rate is decreasing and 5-chloro-2-methyl-isothiazolin-3-one plus 2-methyl-isothiazolin-3-one's rate, after a rapid rise, seems to have stabilized. Although very important constituents of cosmetics, preservatives not only induce allergies on the face but also on the hands, and, as expected, the allergy rate in men and women generally differs. Among the 5 formaldehyde-releasers, there are some favoured simultaneous reactions: quaternium-15 and formaldehyde, and diazolidinyl urea and imidazolidinyl urea. Concomitant reactions between 1-bromo-2-nitropropane-1,3-diol and formaldehyde are not common, and those between 2-bromo-2-nitropropane-1,3-diol and diazolidinyl urea, and formaldehyde are not very common. This supports the hypothesis that allergic reactions to the Germalls are directed toward the initial molecule rather than to formaldehyde.

Autoimmune progesterone dermatitis: absence of contact sensitivity to glucocorticoids, oestrogen and 17-alpha-OH-progesterone

Autoimmune progesterone dermatitis is a rare condition, characterized by recurrent premenstrual exacerbations of a dermatosis, in which sensitivity to progesterone can be demonstrated. The sensitizing mechanism is unknown. The aim of this study was to test the hypothesis that cross-sensitivity between steroid groups could induce allergy to endogenous progesterone in these patients. 5 patients with autoimmune progesterone dermatitis and 1 with oestrogen-sensitive dermatitis have been patch tested with a corticosteroid series, conjugated oestrogen 1% in petrolatum (pet.), and 17-alpha-OH-progesterone 2% pet. There were no immediate or delayed reactions at 2 and 4 days to any steroid group. We have therefore been unable to demonstrate steroid cross-sensitivity, or a use for 17-alpha-OH-progesterone in the investigation of oestrogen - and progesterone-sensitive dermatoses.

Cement dermatitis in underground workers during construction of the Channel Tunnel

The construction of the Channel Tunnel is one of the largest civil engineering projects ever undertaken. The British drive employed 5900 underground workers, and a number developed dermatitis during 1990/1991. As a result, the Translink Joint Venture (TLJV) Medical Centre set up a surveillance programme aiming to monitor and investigate the men working closely with cement as well as other groups of workers with skin problems. Men attended the Medical Centre voluntarily and were assessed, including history, examination and patch tests to a series of 15 test substances (from the European standard series) where indicated. A programme of education about the hazards of working with cement was instituted, including leaflets, videos, local newspaper articles and personal explanation by the Medical Centre staff. Between January 1990 and January 1992, 1138 men were seen at the Medical Centre regarding their skin and 332 were diagnosed as having occupational dermatitis, past or present. Patch tests were performed on 180 men from all trades. Of the 800 grouters, 466 (58 per cent) were assessed and 111 had a history of occupational dermatitis at some time. Many gave a history of a single episode of dermatitis during a particularly hot and wet phase of tunnelling. Patch tests performed on 86 grouters showed allergy to chromate in 56 (65 per cent). Of the 466 grouters assessed, 17 per cent had positive patch tests to chromate but men with no skin problems past or present were not patch tested. Cobalt allergy was often found with chromate allergy (50 out of 56).(ABSTRACT TRUNCATED AT 250 WORDS)

Allergic reactions to a hairdressers' series: results from 9 European centres. The European Environmental and Contact Dermatitis Research Group (EECDRG)

To obtain data on the frequency of sensitization among European hairdressers, the patch test results from 9 centres were evaluated. 8 allergens recommended by the ICDRG and EECDRG in the hairdressing series and PPD from the standard series were used to patch test 809 hairdressers and 104 clients suspected of contact sensitization. Among hairdressers, the mean frequencies of sensitization ranked as follows: GMT 19%, PPD 15%, APS 8%, PTD 8%, ONPPD 4% and PADH 4%. In contrast to GMT in acid permanent waves, the frequency of sensitization to AMT in alkaline permanent waves was only 4%. Frequencies of sensitization to pyrogallol and resorcinol were 0.8% and 0.6%, respectively. The frequencies of sensitization showed marked regional variations, particularly that to GMT, which was highest in Germany (51%), followed by Spain (22%) and London (19%). Clients of hairdressers showed a similar rank order of sensitization frequency, with the exception of APS, which was completely negative in this (small) series.

Irritant contact dermatitis in warehouse employees

A detailed survey of skin complaints amongst 114 airline employees working in a new warehouse revealed 26 cases of skin problems which originated during the 2 1/2 year operation. A clinical survey of broadly the same population confirmed 14 cases from 98 employees as chronic irritant contact dermatitis of the hands. The work involved the reception, unpackaging, inspection, repackaging and dispatch of aircraft parts. The source of the skin irritation was not to be found in the work itself. Rather, the presence among the employees of two severe cases of non-occupational eczema, combined with the idea that incoming aircraft parts from foreign countries might be 'dirty' in some way, had caused a heightened perception of a risk of skin disease, and the frequency of hand washing had increased as a result. Over-frequent hand washing in a few employees had resulted in precisely what the warehouse staff had been trying to avoid.