Bullous haemorrhagic dermatitis induced by heparins and other anticoagulants: 94 cases from French pharmacovigilance centres and a literature review

BACKGROUND

Bullous haemorrhagic dermatitis (BHD) is an uncommon and highly particular side effect of various forms of heparins.

METHODS

To better characterise the disease, we collected all cases from French Pharmacovigilance centres recorded over a 20-year period (37 cases) and performed a Medline literature search up to June 2020 (57 cases).

RESULTS

In all, 94 patients were identified (male/female ratio: 2.2) of mean age 73.5±12.1 years (31-94). Patients were treated with enoxaparin (n=66), unfractionated heparin (n=11), fondaparinux (n=10), tinzaparin (n=4), bemiparin (n=1), reviparin (n=1), dalteparin (n=1), and 4 with other anticoagulants: warfarin (n=3) and rivaroxaban (n=1). All cases presented with 1 to more than 100 haemorrhagic vesicles and bullae, distant from the injection sites, located mainly on the lower (75%) or upper limbs (69%). The lesions were asymptomatic, except in 5 patients who had pruritic or painful lesions. The interval between treatment initiation and BHD ranged from 6 hours to 30 days (mean: 8.4±7 days). Biopsy (n=53) showed intraepidermal or subcorneal cavity with red cells (n=39) or junctional blisters (n=10), with eosinophilic infiltrate only rarely. Direct immuno-fluorescence was negative in 19/20 cases and indirect immunofluorescence was negative in 8/8. The outcome was favourable in all cases, including in 12 patients for whom heparin was maintained. A 93-year-old patient died of compressive haematomas unrelated to BHD. We found 5 cases similar to BHD due to other anticoagulants.

DISCUSSION

This is the largest comprehensive series of this adverse effect due to heparins or, more rarely, to other anticoagulants. Dermatologists must be aware of BHD, since this benign side effect does not necessarily require interruption of treatment. It is rare, considering the large-scale prescription of heparins, and occurs mainly in male patients aged over 70. Although the presentation is highly typical, the physiopathology is difficult to understand, as coagulation parameters are usually normal. Aging, skin fragility or mechanical factors might play a role.

Incidence of serious adverse drug reactions in general practice: a prospective study

BACKGROUND

Many studies have been conducted to estimate the incidence and economic impact of adverse drug reactions. Most of these studies used historical data or were based on single hospital units. Little is known, however, about the frequency of serious adverse drug reactions in general practice.

OBJECTIVE

To estimate the incidence of serious adverse drug reactions in the community.

METHODS

A prospective study during 5 consecutive working days between March 1 and April 30, 1998, was conducted among a random representative sample of 254 general practitioners in Aquitaine, France. The main outcome measure was the number of serious adverse drug reactions (ie, resulting in death, life-threatening condition, hospitalization, incapacity, or sequel) observed by each general practitioner during the study period and validated by an expert panel.

RESULTS

Thirteen validated serious adverse drug reactions, 2 of which were fatal (1 subarachnoidal hemorrhage with oral anticoagulant and 1 aplastic anemia with antineoplastics), were observed, resulting in an incidence density of 10.2 (95% confidence interval [CI], 5.4 to 17.5) per 1000 days of practice. Eleven case subjects (84.6%) were hospitalized. This represents an average of 2.6 cases per general practitioner per year, and 123,000 adverse drug reaction cases (95% CI, 65,400 to 210,000) for the 60,000 general practitioners in France. Antineoplastics and anticoagulants were the drugs most frequently involved, and blood dyscrasia and bleeding were the most frequent adverse drug reactions.

CONCLUSION

This study, which is one of the few available that has prospectively measured the incidence of serious adverse drug reactions in general practice settings, confirms that serious adverse drug reactions are a major public health concern.

[The French system of evaluation of dependence: establishment in a legal system]

The French system of evaluation of dependence has been defined in the French Public Health Code by decree 99-249 of 31 March 1999. It was created by health authorities 10 years earlier and concerns dependence and abuse, which were previously just submitted to control under the designation of non-conforming use and misuse. The consultative function of the narcotics and psychotropics commission has been reinforced and its mission extended to include evaluation. Cooperation with different actors has been organized. This is based on the complexity of the methods of evaluation and the impact of decisions concerning control and/or information. The same principles organize the cooperation of this system at the European and international levels.

Adverse drug reactions: physicians' opinions versus a causality assessment method

Since spontaneous reporting of adverse drug reactions depends on the physician's opinion of the relationship between the drug and the adverse event, we compared physicians' opinions with the scores obtained by the causality assessment method used in France. During a 2 month period, all physicians who reported adverse drug reactions (ADRs) to our pharmacovigilance centre expressed their opinions on the causal link by means of visual analogue scales. ADR reports were then assessed with the French causality assessment method by a clinical pharmacologist who was blind to physicians' opinions. The assessment by both physicians and the standardized method was performed for 75 ADR cases involving 120 drugs. Physicians used a wide range of assessments, with a preponderance of extreme scores, resulting in a U-shaped distribution, while the standardized method gave generally low scores. Scores given by physicians were very high (causality considered very likely or likely) in 60% of cases and very low (causality considered unlikely or dubious/possible) in 32% of cases. Scores obtained using the causality assessment method were low (causality dubious/possible) in 89% of cases and causality considered likely in only 11 cases, essentially in cases with positive rechallenge. Complete agreement occurred in only 6% of cases. Adding complete agreement and minor discrepancies raised the percentage to 49%.