Effect of topical indomethacin on allergen-induced dual skin reactions

Interactions between histamine and prostanoids in IgE-dependent, late cutaneous reactions in man

The contribution of histamine and cyclooxygenase metabolites of arachidonic acid to the wheal-and-flare reaction (WFR) (0 to 30 minutes) and the late cutaneous reaction (LCR) (1 to 24 hours) evoked by intradermal injection of antihuman IgE was appreciated in a comprehensive study of human volunteers treated with H1 and H2 antihistamines, cyclooxygenase inhibitors, as well as the combination of both types of drugs. The findings reinforce the concept that histamine is the major, but not exclusive, mediator of the WFR. In contrast, histamine accounted for but a limited portion of the LCR, but 48 hours of pretreatment with three different cyclooxygenase inhibitors, acetylsalicylic acid, indomethacin, or diclofenac sodium, had but a minor influence on the WFR, whereas all drugs produced a distinct overall inhibition of the LCR. However, for indomethacin, the inhibition was preceded by a potentiation (at 1 to 2 hours), which was abolished by antihistamines, suggesting increased histamine release from skin mast cells after cyclooxygenase inhibition. Furthermore, there was synergism between indomethacin and antihistamines during the LCR, and the combination of diclofenac sodium with antihistamines produced additive inhibition. It is proposed that cyclooxygenase products, such as prostaglandins and thromboxanes, contribute to IgE-dependent skin reactions, both as modulators of mediator release and as vasoactive mediators.

The effect of indomethacin on the kinetics of histamine, 48/80 and antigen wealing

1. The kinetics of weal formation and disappearance following intradermal injection of histamine, compound 48/80 and antigen were measured in indomethacin and inert geltreated human forearm skin. 2. Rates of formation went in descending order for histamine, 48/80 and antigen; rate constants of disappearance for equal sized weals were the same for histamine and 48/80 but were much less for antigen. The corresponding half-lives were 77, 73 and 160 min for histamine, 48/80 and antigen weal disappearance respectively. 3. Cyclo-oxygenase inhibition by topical indomethacin had no effect either on the immediate weal and flare responses or on the rates of formation and disappearance of the weals. 4. These findings together with previous studies using H1-receptor antagonists indicate that 48/80 acts by histamine release but that antigen releases both histamine and an additional material or materials which are not related to cyclo-oxygenase activity. 5. Exacerbation of chronic idiopathic urticaria by cyclo-oxygenase inhibitors is therefore likely to be part of the urticarial disease process.

Prostaglandin D2 and histamine during the immediate and the late-phase components of allergic cutaneous responses

With a skin blister technique in which the mediators generated by the trauma of forming the blister are allowed to subside, we have collected human interstitial skin fluid during the course of allergic reactions to ragweed, and measured levels of histamine and prostaglandin D2 (PGD2). Of 18 ragweed-allergic individuals tested, 11 developed both an immediate and a late-phase reaction (LPR) with fivefold-elevated levels of histamine (40 ng/ml) at 30 minutes and a peak level of PGD2 (6.5 ng/ml) later at 2 1/2 hours after ragweed challenge. The other seven allergic individuals had immediate reactions without an LPR lesion and demonstrated somewhat smaller elevations of histamine (25 ng/ml) but much lower levels of PGD2 (1.6 ng/ml; p less than 0.05). The time course of appearance of these mediators was identical in both groups of patients. The fluids from unchallenged blisters of allergic and nonallergic patients and the fluids of nonallergic patients challenged with ragweed had similar levels of histamine, at the lower limit of detection, and undetectable PGD2 levels. The peak levels of PGD2 in allergic individuals correlated with the size of the LPR lesion (p less than 0.05). These data suggest that the LPR involves the secondary elaboration of mediators different from mediators responsible for the immediate manifestations of the allergic skin reaction.

A study on late allergic reactions to house dust mite in bronchial asthmatics

Patterns of skin and bronchial reactions to the allergen were examined in thirty perennial asthmatics who showed a positive early cutaneous reaction (ECR) to the skin prick test with Dermatophagoides farinael. A dualcutaneous reaction (DCR) was elicited in nine subjects by the skin prick test and in twenty-four by the intradermal test. The size of the late cutaneous reaction (LCR) to the intradermal test was found to correlate with that of the preceding ECR. A bronchial provocation test resulted in no reaction in six, and isloated early asthmatic reaction (EAR) in three, and a dual asthmatic reaction (DAR) in twenty-one. A large LCR was associated with the occurrence of DAR and the patients with a large LCR required a lower allergen concentration to elicit an EAR.

Effect of betamethasone on the dual reaction to anti-human IgE in man: influence of time interval between administration of drug and anti-IgE

The influence of the time interval between administration of a glucocorticoid, betamethasone, and anti-IgE on the effect of the drug on the early and late phase response (LPR) to anti-IgE was examined in 38 volunteers in a randomized controlled study. The immediate flare and wheal responses to intradermally (i.d.) injected anti-IgE were inhibited by approximately 20 and 30% respectively by a 10 day i.d. pretreatment period with repeated 50 micrograms doses (total 300 micrograms) of betamethasone (P less than 0.01), whereas responses to histamine were not influenced. A single i.d. injection of 50 micrograms betamethasone 24 h prior to anti-IgE challenge attenuated the wheal response (P less than 0.05), whereas injection of the drug 2 h prior to and together with anti-IgE had no influence on the early response. Corresponding LPRs were reduced approximately 30% throughout the observation period of 1-24 h (P less than 0.01). Injecting the drug i.d. 30 min following anti-IgE challenge had no significant influence on the total observation period (1-24 h) of the LPR but antagonized the LPR by 35% at 6-24 h (P less than 0.01). It is concluded that glucocorticoids inhibit IgE-dependent LPRs. When extending the topical pretreatment period with the compounds also the early part of the allergic reaction is attenuated.

Inhibition of the late phase response to anti-IgE in humans by indomethacin

The hypothesis of cyclooxygenase derivates of arachidonic acid as putative mediators of late phase skin reactions (LPR) was evaluated by studying the effect of indomethacin and naproxen on anti-IgE elicited skin reactions in healthy volunteers. Indomethacin 50 mg t.i.d., 48 h prior to and up to 24 h following challenge with anti-IgE 1/3300 (v/v), produced a slight attenuation of the flare response and a 35% inhibition of the LPR (P less than 0.05) at 1-24 h as compared with placebo (n = 11). Naproxen, 250 mg, b.i.d. showed analogous anti-LPR effect (n = 4, P less than 0.05). Intradermally (i.d.) injected indomethacin, 75 micrograms (7 X 10(-3) mol/l), attenuated the flare and LPR to anti-IgE 1/330 at 1-6 h (n = 12, P less than 0.01). Indomethacin, oral and i.d., enhanced the LPR to various dilutions of anti-IgE in 30% of the individuals. The results suggest that prostaglandins and thromboxanes participate in the development of an LPR in human skin.

Suppression of immediate and late anti-IgE-induced skin reactions by topically applied alcohol/onion extract

In a double blind study, alcohol/onion extract (5% ethanol) was injected simultaneously with 20 IU and 200 IU rabbit anti-human-IgE intradermally in 12 adult volunteers (6 atopics, 6 non-atopics). Diameters of wheals and flares were measured 10 min after and compared with control sites challenged with 20 IU and 200 IU anti-IgE in a 5% ethanol solution. The skin sites were then treated epidermally with 45% alcohol/onion extract and 45% ethanol under occlusion. Diameters of late cutaneous reactions were measured hourly. Oedema formation was clinically estimated according to an arbitrary scale and skin thickness measured with a calliper. In the onion-treated skin sites the wheal areas were significantly reduced (20 IU: control: 108 +/- 53 mm2; onion 69 +/- 42 mm2, P less than 0.05; 200 IU anti-IgE: control: 152 +/- 25 mm2, onion: 138 +/- 26 mm2, P less than 0.02). The oedema formation during the late phase skin reaction was markedly depressed (P less than 0.005 at 2 h, P less than 0.01 at 4 and 6 h, P less than 0.02 at 8 h). The extent of late skin reactions was slightly, but not significantly reduced. Obviously, onions contain pharmacologically active substances with anti-inflammatory and/or allergic properties.

Platelet-activating factor: a possible mediator of the dual response to allergen?

Certain allergic asthmatic patients exhibit a dual response in the lung following bronchial challenge with the appropriate allergen. Often this is paralleled by a cutaneous dual response when the antigen is injected intradermally. The mechanisms underlying such phenomena are not established, but some evidence suggests that the late response is a consequence of the early response. Since platelet activation has been observed following antigen challenge in asthmatic subjects, we have studied the ability of platelet activating factor (PAF-acether, AGEPC) to induce cutaneous inflammatory responses in man. In a time course study over 24 hr, PAF-acether produced a biphasic response: an immediate weal and flare reaction, which resolved within 1-2 hr and was followed some 3-6 hr later by a delayed reaction in which erythema associated with hyperalgesia was evident. These observations suggest that PAF-acether should be considered in the context of allergic asthma as a possible mediator of the dual response to allergen.

Inflammatory characteristics of platelet activating factor (PAF-acether) in human skin

The phospholipid PAF-acether is released from a range of inflammatory cell types and, in experimental animals, has properties appropriate to a mediator of inflammation. We have studied the inflammatory characteristics of intradermally injected PAF-acether in human skin. An early weal and flare response was succeeded, in a proportion of subjects, by an area of late-onset erythema at the site of the resolved weal, reminiscent of the dual response to allergen in sensitized individuals. The time-course and dose-response relationship of the early response has been determined and a synergistic interaction between PAF-acether and prostaglandin E2 established. PAF-acether should therefore be considered as a potential mediator of both acute and persisting inflammation in man.

Inhibition of the late asthmatic response to house dust mite by non-steroidal anti-inflammatory drugs

Bronchial provocation with house dust mite allergen in subjects allergic asthma may be followed by an early and a delayed phase of bronchospasm. The latter can be prevented by DSCG or by corticosteroids. A representative subject was studied to determine the effect of non-steroidal anti-inflammatory drugs (NSAIDs) on the late reaction. Indomethacin, benoxaprofen or acetylsalicylic acid given before allergen exposure inhibited the delayed bronchospasm. Sodium salicylate was ineffective, as were indomethacin or benoxaprofen when given after the early phase of bronchospasm. The mechanism of action of these compounds was thought to be by inhibition of arachidonic acid metabolism via the cyclo-oxygenase pathway and this appears to be a pre-requisite for the appearance of a late reaction following house dust mite inhalation.