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A 23-year-old man has a reaction after being given oral penicillin for a sore throat.
Penicillin can cause numerous allergic reactions, including anaphylaxis, interstitial nephritis, rashes (the most common manifestation), urticaria, fever, pneumonitis, dermatitis, and even asthma in workers exposed to airborne penicillin. Hemolytic anemia is often IgGmediated. Skin tests are reliable in predicting low risk (similar to general population) for those claiming previous penicillin reactions, and desensitization is feasible. The frequency of reactions to cephalosporins in penicillinallergic patients is not definitely known.
A 56-year-old woman is given an angiotensinconverting enzyme (ACE) inhibitor for control of hypertension and develops a reaction consisting of urticaria.
ACE inhibitors can cause angioedema of the face and oropharyngeal structures. This is felt to be a pseudoallergic reaction, possibly due to the drug’s effect on the kinin system. It is thought that reactions may be more common in women, Blacks, and those with idiopathic angioedema. If this occurs, therapy with alternate ACE inhibitors should not be attempted.
A 23-year-old man has an exacerbation of asthma when he takes aspirin for a headache.
Aspirin frequently can precipitate asthma in susceptible individuals. At highest risk are asthmatics with chronic rhinosinusitis and nasal polyps. This is probably a pseudoallergic reaction related to inhibition of cyclooxygenase with a resultant enhancement of leukotriene synthesis or effect. Densensitization regimens have been developed.
A 29-year-old man presents with severe back pain and a red eye. The pain is located in his lower back and gluteal area, and is associated with morning stiffness that improves after several hours. On examination, he has limited forward flexion and tenderness of the ischial tuberosities.
Ankylosing spondylitis and HLA B27
A 24-year-old woman has a facial skin lesion, thrombocytopenia, arthralgia, and pericarditis.
SLE is a multigenic disorder.
A 14-year-old girl presents with weight loss, increased thirst, and urination. Her laboratory tests reveal hyperglycemia and a mildly increased anion gap metabolic acidosis.
Type I diabetes mellitus and HLA DR3
A 22-year-old man with iritis, balanitis, urethritis, and arthritis.
Reiter syndrome and HLA B27
A 27-year-old woman has severe symmetrical small joint arthritis. She notices 1 hour of morning stiffness and swelling with redness in her wrists and hand joints. The distal finger joints are spared. X-rays of the hands reveal early bone erosion in some of the joints.
RA and HLA DR4
A 33-year-old policeman develops acute asymmetric arthritis involving his left knee and ankle and right ankle. The pain in the feet prevents him from walking. He recalls having a diarrheal illness 3 weeks ago.
Reactive arthritis (e.g., Shigella or Yersinia) and HLA B27. The relationship between HLA antigens and diseases is not absolute, but rather one of increased relative risk. The presence of HLA B27 increases the relative risk of ankylosing spondylitis by a factor of about 80, of Reiter syndrome by a factor of 40, and also increases the likelihood of reactive arthritis. The presence of HLA DR4 increases the likelihood of juvenile RA by a factor of 7 and RA by a factor of 6. The presence of HLA DR3 increases the likelihood of both SLE and insulin-dependent diabetes mellitus by a factor of approximately 3.
A 73-year-old man has a history of recurrent pneumonias. He now complains of bone discomfort in his back and chest. X-rays reveal multiple lytic lesions and his serum protein electrophoresis has an IgG spike of 12 g/dL.
Multiple myeloma and B-cell deficiency/ dysfunction
A 22-year-old woman notices multiple lymph nodes in her neck. They are nontender on palpation and mobile. A monospot test is negative and a biopsy of the node reveals Hodgkin’s disease.
Hodgkin’s disease and T-cell deficiency/ dysfunction
A 73-year-old man has 30,000/mL mature lymphocytes on his blood film. This is an incidental finding and he is clinically feeling well.
Chronic lymphocytic leukemia and B-cell deficiency/dysfunction
A 24-year-old woman with malar rash, thrombocytopenia, and arthralgia.
SLE and complement deficiency
A 69-year-old man is receiving chemotherapy for acute myeloid leukemia.
Therapy for hematologic malignancy and neutropenia
A young woman with ataxia-telangiectasia syndrome.
Ataxia-telangiectasia and both T- and B-cell dysfunction. Multiple myeloma and chronic lymphocytic leukemia are two of the more common causes of B-cell deficiency/dysfunction. Hodgkin’s disease, AIDS, sarcoidosis, and thymic aplasia or hypoplasia result in T-lymphocyte depletion/ dysfunction. SLE has been associated with C3 deficiency, but most severe complement deficiencies result from inherited disorders. Ataxiatelangiectasia, common variable hypogammaglobulinemia, severe combined immunodeficiency, and Wiskott-Aldrich syndrome have mixed T- and B-cell deficiency.