Environmental Medicine Integrating a Missing Element into Medical Education (1995) / Chapter Skim
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Case Study 50: Skin Lesions and Environmental Exposures: Rash Decisions
Case Study 50: Skin Lesions and Environmental Exposures: Rash Decisions
Pages 817-861
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From page 817... ...
Or In some cases, skin lesions are a diagnostic clue to the presence of systemic ~ ~ toxicity. This monograph is one in a series of self-instructional publications designed to increase the primary care providers knowledge of hazardous substances in the environment and to aid in the evaluation of potentially exposed patients.
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From page 818... ...
What are the most likely nonoccupational etiologies for four of the more common skin conditions: irritant and allergic contact dermatitis, urticaria, and photosensitivity?
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From page 820... ...
(1bJ What are the most likely causes of the woman's rash? (1cJ How would you treat the skin lesions experienced by these patients?
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From page 821... ...
Irritant contact dermatitis caused by chronic exposure to mild irritants typically begins with erythema and progresses to eczema with exudative vesicles and papules, most often limited to the area of direct contact. Itching, stinging, and burning sensations may be noted—especially with stronger irritants—but are generally not as severe as symptoms of patients who have allergic contact dermatitis.
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From page 822... ...
, although some substances, such as some alcohols, oils, and glycols cause irritant contact dermatitis in only a small percentage of exposed persons. In contrast, strong irritants, such as concentrated mineral acids, alkalies, and amines, cause chemical burns or irritant contact dermatitis in almost everyone exposed.
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From page 823... ...
Routine skin biopsy generally is not helpful because the histologic appearance of irritant and allergic contact dermatitis is similar. However, unlike allergic contact dermatitis, irritant contact dermatitis tends to localize at the exposed area and to cause mild itching and more erythema than vesiculation.
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From page 824... ...
Some over-the-counter and prescription topical medications or their excipients can further irritate the skin or provoke allergic contact dermatitis. Administering mild sedatives and antihistamines to relieve itching may also be beneficial.
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From page 825... ...
CASE STUDY 50: SKIN LES ONS ~ E~IRO~E=^ E~OSU~S Table 2. Groups of topical corticosteroid products, in order of decreasing potency.
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From page 826... ...
He has no direct contact with industrial cleaning agents or carbonless copy paperin his work. He does have contact with chemicals through his woodworking hobby.
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From page 827... ...
O The clinical and histologic appearances of allergic and irritant contact dermatitis are similar. Allergic contact dermatitis results from a true allergic (i.e., cell-mediated)
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From page 828... ...
Some chemical groups known to cause allergic contact dermatitis Aromatic amines Benzothiazoles Caine-type anesthetics Ethylenediamine compounds Halogenated germicides Hydroxyquinolines Phenolic compounds Phenothiazines Streptomycin group of antibiotics Thiurams Common Etiologies O Aromatic compounds with polar or ionic substituents are potent sensitizing agents.
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From page 829... ...
Allergic contact dermatitis is often misdiagnosed as irritant contact dermatitis. Otherconditions to consider in the differential diagnosis are atopic dermatitis, pustulareruptions on the palms and soles, psoriasis, Herpes simplex and Herpes Roster, insect bites, parasite infestation such as scabies, fungal infections of the feet with idiopathic vesicular reactions.
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From page 830... ...
Because the histologic appearance of lesions due to allergic or irritant contact dermatitis is the same, routine skin biopsy is not helpful in their differentiation. O The cilnical and microscopic appearances of skin lesions due to allergic contact dermatitis are the same as those due to irritant contact dermatitis.
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From page 832... ...
However, only two of the children who have rashes have been involved in this activity. All the affected children had participated in a craft class in which they made lime sachets by puncturing lime skins and inserting sprigs of cloves over the surfaces of the limes.
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From page 833... ...
Germicides in soaps and detergents may also cause photosensitivity dermatitis. A major epidemic of allergic contact dermatitis occurred in Great Britain in 1960 afterthe introduction of two soaps that contained tetrachlorosalicylanilide, a photoactive antibacterial agent.
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From page 834... ...
Diagnosis Photoallergy from chemical contact must be differentiated from polymorphous light eruption, systemic lupus erythematosus, pellagra, derrnatomyositis, porphyria, allergic contact dermatitis and photoallergic drug reaction. A thorough history of medication treatment will usually rule out photoallergic drug reaction.
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From page 836... ...
Fen, Jim (4a) Is the skin condition described by the patient consistent with a reactivation of acne wigaris?
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From page 837... ...
A few cases of chloracne have persisted for 30 years or more after contact with the chloracnegenic agent has ceased. O Chlorinated aromatic Many chlorinated aromatic hydrocarbon compounds used in the work hydrocarbons cause place can cause chloracne.
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From page 838... ...
A history of exposure to agents known to cause Chloracne and the typical appearance of the rash on physical examination are usually sufficient for diagnosis. Chloracne may be distinguished from acne vulgaris by the distribution of the lesions, age at onset, and morphology.
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From page 840... ...
Two of the children have histories of itchy, weeping, vesicular rash on the neck and face that cleared before the pigment changes became noticeable. A public health evaluation of the drinking water and food served at the school has not revealed toxic or infectious agents.
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From page 841... ...
In hypopigmentation, depigmentation probably occurs either by damage to the melanocyte, which leads to cell distortion and death, or through inhibition of melanin synthesis by the offending substance. It may be significant that industrial compounds that cause hypopigmentation (Table 5)
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From page 842... ...
Treatment No effective treatment exists to reverse pigment changes. Hypopigmentation may last months to years after contact with the offending substance is discontinued, or it may be permanent.
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From page 843... ...
~ TSDR V with clothing, has, and gloves. Topical bleaching cmams prepaid from hydmqulnone or as monobenzyi ether must be used caudous~ 10 p~ven1 wldesp~d dep~ment~ion.
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From page 844... ...
844 APPENDIX C Skin Lesions Case 6 Contact Urticaria A 3s-year-old woman consults you because of episodes of generalized hives that develop about20 minutes after she uses certain brands of shampoo. The hives are preceded by sensations of itching, burning, and stinging of the skin on the scalp, upper face, and posterior aspect of the neck.
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From page 845... ...
The reaction remains localized. Immunologic contact urticaria is an immediate allergic reaction in persons who have previously become sensitized to the offending agent.
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From page 846... ...
Table 6. Some substances that cause allergic contact urticaria Animal products Foods dander hair saliva serum Common Chemicals ammonia alcohol parabens polyethylene glycol Cosmetics hair products nail polish perfumes eggs flour fruits & vegetables meats milk nuts seafood spices Plant products henna latex rubber papain strawberries woods Textiles silk wool Medications bacitracin Miscellaneous cephalosporins acrylic monomer chloramphenicol epoxy resin gentamicin formaldehyde neomycin nylon salicylic acid seminal fluid Nonimmunologic contact urticaria has been provoked by contact with substances as diverse as acids (acetic, benzoic, butyric, cinnamic, sorbic)
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From page 847... ...
Testing should be done by, or in consultation with, a dermatologist; resuscitation equipment and medications should be available in case a severe anaphylactoid reaction results. Trealment O Antihistamines can alleviate symptoms of urticana.
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From page 848... ...
The man has a lesion on the right cheek that appears to be a basal cell carcinoma. Both patients complain of numbness and tingling in the feet and a general feeling of fatigue.
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From page 849... ...
O Reasons for the 700% increase in malignant melanoma in the past 60 years have not been well established. O PAHs and inorganic arsenic are well-known causes of cancerous skin lesions.
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From page 850... ...
O Sunlight is the most important cause of malignant melanoma. Diagnosis All potentially cancerous skin lesions must be differentiated from benign lesions.
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From page 851... ...
Surgical excision and radiation are the most common treatment modalities for localized malignant skin lesions. All excised tissue should be sent for histologic examination to confirm the diagnosis and to be certain that an adequate margin of normal skin was removed.
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From page 852... ...
Referring patients to, or consulting with, a dermatologist who can perform or interpret dermatologic diagnostic testing, may be advisable. Patch Testing Patch testing is frequently used to differentiate between allergic contact dermatitis and other forms of dermatitis.
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From page 853... ...
Microscopic examination of the specimens obtained can allow differentiation between benign and malignant skin conditions. Irritant and allergic contact dermatitis cannot be readily differentiated on routine skin biopsy.
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From page 854... ...
Irritant and Allergic Contact Dermatitis Abel EA, Wood GS. Mechanisms in contact dermatitis.
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From page 855... ...
Photochem Photobiol 1984;39:861-8. Sources of /nformation More information on skin lesions and treating and managing cases involving skin lesions due to environmental exposure can be obtained from ATSDR, your state and local health departments, and university medical centers.
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From page 856... ...
The presence of mild rather than severe itching, more erythema than vesiculation, localized lesions, and insidious rather than explosive onset are more consistent with irritant contact dermatitis than with allergic contact dermatitis.
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From page 857... ...
However, vesiculation would be expected with allergic contact dermatitis. Patch testing could rule out this diagnosis.
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From page 858... ...
6 is consistent with contact urticaria syndrome. Balsam of Peru and various alcohols (especially propyl alcohol and ethyl alcohol)
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From page 859... ...
allergic contact d. A delayed type of induced sensitivity (allergy)
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From page 860... ...
Decreased pigmentation of the skin. keratosis.
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From page 861... ...
Hives; an immediate eruption of itching wheels, which may be due to physical and chemical agents, foods or drugs, foci of infection, or psychic stimuli. urticaria syndrome.
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