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6- Allergic Reaction

Allergy and HIV

- It is possible with HIV patients to have an allergic reaction to a drug that was taken in the past without causing any problems.  (Especially Bactrim…)!!!  Consider that any form of allergy can be caused by any allergen...  Nearly any drug can cause urticaria, rash, Steven-Johnson, Lyell, anaphylactic shock...

- If no alternative curative drugs are available, we sometimes have to accept mild allergic reactions or other side effects of drugs.  Continue to give the curative drugs that cause the allergy and add mild symptomatic drugs (calamine, chlorpheniramine, betamethasone cream, prednisolone)…  Reactions such as mild eczema (pxx002), (pxx003), jaundice (xxx010) or pruritus are sometimes "a lesser evil"…  BUT we certainly should not continue any treatment that is causing Stevens Johnson/erythema multiforme (bxx017...) (see "32-Unable to eat" & "17-herpes") "Lyell's syndrome" (pxx008...)  (pxx166...) (See "30-Lyell"), acute urticaria (ptx023...)  (pxx127...) + bronchospasm or severe generalized erythroderma (pxx025...)  (pxx164) (See "30-erythroderma"), or hemorrhagic syndrome (bxx050) (pxx258)

- Be careful when you see abnormally dark skin/lips on a patient (bxx008) (pxx005)…  Such patients seem to be more subject to severe allergic reactions ...See "30-black syndrome"

- Bactrim is one of the most useful drugs for us but is also the main cause of allergic problems.  If we are not sure of the origin of an allergic reaction, we first try replacing Bactrim with dapsone…(+ trimethoprim in context of PCP etc.)  But if allergic reactions persist, we can assume that Bactrim is not the cause...  Don't forget to change back again to Bactrim treatment because it works better than dapsone (especially for prevention of PCP).

- For us it is clear that after Bactrim, TB drugs (rifampicin) are the most dangerous drugs (in terms of allergic reactions)...  See "TB".  However, surprisingly enough, in our hospice we often have to inject ampicillin, haloperidol, diazepam, domperidone, tramadol…and we've never had serious problems with these drugs.


Allergy test

In a poor hospice, a useful technique to determine the sensitivity of a patient to a particular drug is to make two similar scratches on the skin.  On one scratch put one drop of physiological liquid and on the other one drop of the same liquid mixed with the drug you want to test.  After 15 minutes, if you can observe severe reaction on second scratch that you cannot observe on the first scratch, you can consider that patient is allergic to that drug.


Different kinds of allergy

Lyell's syndrome (or "Bullous epidermolyse/exfolliative dermatitis" or "toxic epidermal necrolysis")

// pxx008...// pxx118...// pxx165...// pxx165- 166- axx025- 026// pxx415- 416- 417- 418- 419- 420- 421- 422- 423- 424//

Looks like a second degree burn.  Can involve a very large area of skin.  Main danger is secondary infection and septicemia (ptx017).  Treat with strong preventive (cloxa 500mg 4x/day + fluconazole 200mg 1x/day) + dexamethasone 3cc every morning till it looks less dangerous (dry)(pxx009) (pxx007). Stop Bactrim/sulfadiazine if you do not find another cause.  We feel it is possible to avoid the "full-blown disease" if we stop Bactrim immediately when we see the beginning of bullous lesions (pxx010) on the skin (pxx005) (bxx008).  The lesions become dry immediately when the causative factor has been removed (pxx007), and do not need any further specific treatment...  (The allergy must be confirmed). 

Erythroderma / exfoliative dermatitis

ptx033- pxx022- pxx023- pxx024- pxx025- pxx069- pxx070- pxx131- pxx132- pxx164- pxx215- pxx216- pxx217- pxx234- pxx235- pxx236- pxx237- pxx238- pxx239- pxx240- pxx241- & see "30-Erythroderma"

Intense and widespread reddening of the skin associated with exfoliation.  In an HIV ward the 2 main causes are "acquired erythroderma" (= "acquired ichthyosis") and "erythrodermic psoriasis".  Both can be induced by a drug (including antiviral treatment) but; in practice there is one important difference: unlike "acquired erythroderma"; "erythrodermic psoriasis" will relapse frequently throughout a lifetime, even if you stop the drug that induced the problem.

Treatment of both diseases are basically the same in a poor hospice... dexamethasone high dose for a short time.  If it is erythrodermic psoriasis, it is useless to try to obtain "perfect skin".  The patient will have frequent relapses...  (Dexa during long period is more dangerous than psoriasis for HIV patient: CMV, Mycoses...)

In bad hygienic conditions, secondary infections are acute, severe and often directly generalized (pxx023...) Patients may be sent to a hospice where they are expected to die just because the disease visually appears so frightening and severe.  However, often such patients still have high CD4 counts and are able to have many months/years of normal life.  Treat with high doses of 9-Dexamethasone IM (4cc morning +2cc midday) + gentamycin IM (160mg/day) + fluconazole (200mg 2x/day) if the patient is able to take drugs.  (See "26-Psoriasis")

Stevens Johnson/erythema multiforme versus herpetic stomatitis

-ptx061... -bxx012...- bxx056...- bxx063- yxx010... //pxx435- 436- 437- 438- 439- ptx067// & See "32-unable to eat" & "17-herpes"

Differential diagnosis between "herpes stomatitis" and "Stevens Johnson/erythema multiforme" is sometimes impossible.  Usually, Stevens Johnson/erythema multiforme will involve the entire lip, unlike herpetic stomatitis which is often a localized lesion (see photos + comments: bxx011- 014- 015- 016- 017- 031- 032- 056...- )

- All become more complex when we know that the herpes virus can be the cause of the Stevens-Johson syndrome as well!!! //yxx010- 011- ghx094- 095- 096- pxx381- 382- 383- 384- 385- 398- 399- bxx 065- 066- 067//

In "Stevens Johnson/erythema multiforme" patients may also have generalized skin/mucosa effects (eyes, genitalia (ghx067- ghx074), bullous epidermolysis or other kind of rash especially on the chest (pxx264)...).  No curative therapy is available.  Wait and see with liquid feeding (Soya milk) and local care: H2O2 1.5%, gentian violet, Vaseline…  Often patients recover within 15 days if we stop Bactrim because sulfamides are the main cause of disease (but there are also other rare causes such fluconazole or rifampicin (bxx048) (ptx039) (ptx040) (ptx041).

ATTENTION!  Often it is possible to avoid the "full-blown disease" if we stop Bactrim immediately as soon as we see little bloody wounds on lips (bxx012) (bxx013) (bxx020) which begin to appear on normal or, often, abnormally dark lips (bxx008). If not getting better after 1 day, consider it is the beginning of herpetic stomatitis and try to give acyclovir 800mg 5x/day (if still can eat!?!).

If the cause of Stevens Johnson is not remove, the disease become more and more a "Lyell's syndrome" ( pxx415- 416- 417- 418- 419- 420- 421- 422- 423- 424)


Hemorrhagic syndrome

Petechia (pxx021) (pxxo55) (pxx231) (pxx233) (pxx257) (pxx258), epistaxis, bloody wounds, bloody gums (bxx046), bloody sputum (scx006) (scx007), bloody stools (sfx015) (sfx014) (sfx008) (sfx026), hematoma/ echymosis (pxx232) (pxx247) or hemorrhage anywhere else can be connected with hemostatic problems. In hemorrhagic context, in poor hospice, it is specious to make distinction between "allergic reaction" and "side effect" of a drug... but in HIV hospice there are many other causes of hemorrhagic syndrome including infectious causes (hemorrhagic fever...), carence causes (Vit K, folic acid...), autoimmune diseases...

(NB "vascular hernia syndrome" is a strange bloody disease that we have sometimes observed in our ward.  A few vascular hernias full of blood, disseminated on body, but specially on lips and the border of a former wound.  On the lips it can become a spectacular tumor...  For us, it seems that sulfa is usually the main cause.  See comments under photos: //bxx050... // bxx031... //)

Treatment of hemorrhagic syndrome

  1. Stop diclofenac, aspirin, other NSAIDs…  Give symptomatic treatment if available (We do not have many ways to treat because of lack of lab tests, fresh blood and suitable drugs.)
    • Vit K 1amp IV or IM 1inj 1x/day for 3days
    • Transamine 1tab 3x/day for many days (often useless)
    • Adrenaline mixed with sterile water used topically for epistaxis, wounds…
  2. Check if cause of hemorrhage could be one of the following drugs: Bactrim, chloramphenicol, sulfa.  Difficult to know, of course, but for security, often we stop these drugs if it is possible.

See also "16-Hemorragy"

"Moult syndrome" versus "SSSSS"

//pxx061... //pxx097 //pxx103... //pxx252... // pxx225... //

Dry moult of skin ("dry Lyell").  Large areas of skin peel off.  The face is never affected.  The palms and soles are always involved.  Distribution of lesions is always symmetrical.  Some symmetrical areas of the body are not involved unlike erythroderma... and the crusts are thicker....  General conditions are not affected (no fever, nor other infectious signs...).  Disease resolves without specific treatment but relapses often...  Dermatologists say that the cause of the disease is a soft species of staphylococcus.  BUT our recent experience made us think that this common syndrome (in our ward) can also be an allergic reaction.  (We had a patient who got the "moult syndrome" two times a few days following 2 successive massive allergic reactions...)  It is why we prefer to use 2 different names for the same syndrome.  See "30-SSSSS"

"Black syndrome"

// pxx206... // pxx223... // pxx278... // pxx427... // pxx440 // bxx008 //

Sub acute or chronic evolution.  Never resolves.  Common.  General conditions are not really affected, but patients are more subject to "Steven Johnson" and "Moult syndrome".  Impossible for us to find the cause...  Possibly an allergic cause (?)  Possibly multifactorial (?)  Sometimes, patients present the syndrome without having had any new drugs for months... and sometimes (rare) without having taken any medicine...

Allergic eczema

-pxx002- pxx003- pxx029- pxx098- pxx143-

"Eczema" is a sterile inflammatory condition of the skin with vesiculation in the acute stage.  After the acute stage, typically erythematous, edematous, papular, and crusting eruptions are followed by lichenification and scaling.  Usually, pruritus is present.  The allergy can be caused by a drug as well as a disease, especially a skin infection (Scabies or Tinea are common cause of allergic eczema...).  It is why we always must examine the entire skin, including genital and anal areas before thinking that a drug is the cause of the allergy.


ptx023- ptx024-

An eruption of itching wheals; it may be due to a state of hypersensitivity to foods or drugs, infection, physical agents (heat, cold, light, friction), or psychic stimuli.  Association with bronchospasm is common and as is severe itching.  Because eruption is extremely acute, often the patient himself knows the cause of the allergy.

Treat by suppressing the cause + dexa + bronchodilatator & adrenalin if severe lungs symptoms...

Sub-acute-chronic atypical Bactrim allergy


This patient was worse each day.  Atypical symptoms (diarrhea, loss of weight, vomiting, no appetite etc) He was simply going to die when he started to have symptoms on his lips.  We decided to stop Bactrim and his general condition improved directly!  (And lips as well, of course).  We had to think again of the variety of side effects allergy to Bactrim can cause.  Stevens Johnson is probably only one form of a chronic generalized intolerance that we have to diagnose before patients reach cachexis!

fixed drug eruption

pxx200 //

Macular lesions, often solitary, recuring at the same place... may be multiple. More numerous lesions occur after repeated adminsitration. It take months for lesions to disapear after withdrawing the cause of allergy. Take a feww hours anly to come back.

Contact allergy

pxx209 //

Easy diagnosis. Often, patient knows the cause. Treat with dermovate and prevention of contact with cause.

Acute severe rash +/- bronchospasmus (life is in danger!)


Easy diagnosis. Often, patient knows the cause. Treat with dexa high doses and symptomatic...



In emergency situations:

  • Remove the cause!!  Adrenaline 1mL of 1:1000 IM injections every 10 minutes until improvement observed.  +/- High dose of dexamethasone IM/IV (4cc or more), +/- symptomatic treatment of bronchospasm/dyspnea (ventolin1tab 3-4x/day, aminophylline 1tab 3-4x/day, O2, (see "12-Dyspnea")…)




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