Hypothetical Patient Management
PRURITUS
Obriz M. Paglinawan SWU-MHAM-CM Year III Medical Student, 1999
Dr. Reynaldo O. Joson Facilitator
Comments and Inquiries from Facilitator
(Comments and inquiries are contained in "text boxes or areas.")
Trigger 1
Patient with complaint of a "pruritic skin"
Questions:
1. What is a "pruritic skin"?
It is a disagreeable sensation that provokes a desire to scratch. It is a primary sensory impulse carried on unmyelinated C fibers in the spinothalamic tract. It is modulated by central factors, including cortical ones. Not all cases of pruritus are mediated by histamine, though several mediators - bradykinin, neurotensin, secretin, and substance P - release histamine.
The sensation of itch may be elicited by a wide variety of dermatologic disorders and infections or by external stimuli, such as changes in temperature, stroking, or exposure to noxious agents. Itching may also be one manifestation of a systemic disease. Most systemic and cutaneous (delayed-type hypersensitivity) allergic reactions cause pruritus and often present a most challenging diagnostic problem.
2. What are the possible causes of a "pruritic skin"?
GENERALIZED
LOCALIZED
A. Skin Disorders
B. Systemic Disorders
C. Psychogenic Disorders
D. Infestations
3. What do you think are the more common/least common general and specific condition causing the health problem?
General condition/disorder
Specific condition/disease
Less common
More common
Infestations
Primary Skin disorders
Psychogenic factors
Systemic Disorders
So you think the more common causes are the primary skin disorders and systemic disorders followed by psychogenic disorders. What are the more common specific conditions? Infestations, allergies, chemicals, etc.?
A 7-year-old child male from Cebu City consulted for the first time due to generalized itchiness on his body.
Physical examination:
Skin: (+) rashes all over the body Extremities: dry, scaly, hyperpigmented lichenified
Skin: (+) rashes all over the body
Extremities: dry, scaly, hyperpigmented lichenified
1. What is your primary and secondary diagnosis?
Primary diagnosis: Contact Dermatitis Secondary diagnosis: Scabies
Primary diagnosis: Contact Dermatitis
Secondary diagnosis: Scabies
2. What are the bases for your primary and secondary diagnoses?
Signs/Symptoms
Contact Dermatitis
Scabies
Rashes
present
Pruritus
What conditions present with generalized pruritic rashes accompanied by dry, scaly, hyperpigmented, lichenifed extremities? Are the dry, scaly, hyperpigmented lichenified lesions in the extremities secondary lesions, secondary to scratching due to itchiness? If yes, your diagnosis should focus on conditions producing generalized pruritic rashes. In my opinion, contact dermatitis is usually associated with localized pruritus. Thus, that should not be the primary consideration. Primary considerations will be primary skin disorders that produce generalized pruritic rashes. What produce generalized rashes? Infections and infestations? Viral exanthems can produce generalized rashes. Infestations such as those caused by generalized scabies can also produce generalized pruritc rashes. Because of the dry lichenified hyperpigmented scaly lesions on the extremities, signifying a chronic affair, scabies is more probable than viral exanthems, based on the available data. One would certainly need more data. In your table, you did not demonstrate differences between contact dermatitis and scabies. You did not show the basis for choosing contact dermatittis as your primary diagnosis.
3. Do you need more data (sign/symptom) to firm up your primary and secondary diagnoses? YES
If yes, what? How will it firm up your diagnosis?
Additional Data supplied:
History of playing a pet (+) Hx of Asthma, measles, chicken pox, rhinitis (+) of self-medication such as Caladryl a few months ago (+) Hx of going to the beach for family picnic
History of playing a pet
(+) Hx of Asthma, measles, chicken pox, rhinitis
(+) of self-medication such as Caladryl a few months ago
(+) Hx of going to the beach for family picnic
As mentioned above, more data are needed to firm up initial suspicions of scabies vs viral exanthems. Core data needed will be onset or duration, characteristics of rashes, diffusely generalized or generalized but with concentration on some areas, specific type of rashes, where they started, any identifying precipitating factors, any associated signs and symptoms of systemic inflammation and infection that would suggest viral exanthem. Any previous medical consult? The data you supplied are not very helpful. You have to secure more data based on what I have pointed out in the previous paragraph. In the absence of informative data, I would still consider scabies and atopic dermatitis as the possible causes of a chronic generalized rashes. Do atopic dermatitis or contact dermatitis produce generalized rashes? If they do, they should be considered. With a history of asthma and probably chronic rhinitis (possibly, allergic rhinitis), I would consider atopic dermatitis more than contact dermatitis as the primary diagnosis. Is atopic dermatitis the same as contact dermatitis? The secondary diagnosis could be scabies as this may be a cause of generalized pruritic rashes.
4. Do you need a paraclinical diagnostic procedure?
If yes, why? YES
If the clinical diagnosis is not so certain and the treatment plan is different and to make certain the primary diagnosis.
If no, why?
If the clinical diagnosis is so certain and the treatment plan is the same.
YES, definitely. Since the data you gave are lacking and will not give a diagnosis with certainty. Remember this point. You have to secure as much as data as you can to enable you to come out with a clinical diagnosis. Don't use the availability of paraclinical diagnostic option as an excuse not to get symptom and sign data diligently.
5. If you need a paraclinical diagnostic procedure, what will you recommend? Why?
Give at least 3 options and then compare using benefit, risk, cost, and availability factors. Then select one demonstrating priority on the primary diagnosis. Shotgun policy is NOT acceptable.
Option
Benefit
Risk
Cost
Availability
CBC
++
+
+++
Skin Test
Burrow ink test
You have to be more detailed than giving pluses. Spell out the differences. Considering that your primary diagnosis is contact dermatitis and your secondary diagnosis is scabies, in looking for paraclinical diagnostic options, focus your attention first on the primary diagnosis. Are there reliable paraclinical diagnostic procedures for contact dermatitis? If there are none, consider options for the secondary diagnosis. Is skin test a reliable diagnostic procedure for contact dermatitis? Burrow ink test is a test for scabies, right? CBC is definitely very nonspecific.
6. Suppose the patient agreed to your recommendation of the paraclinical diagnostic procedure and suppose it was done. How do you interpret the result?
Skin test was done for its benefit outweighs the risk and the cost for it is specific for atopic dermatitis so that the primary diagnosis will be more certain. Is atopic dermatitis and contact dermatitis the same? What will be a positive finding of atopic dermatitis or contact dermatitis on skin test?
Skin test was done for its benefit outweighs the risk and the cost for it is specific for atopic dermatitis so that the primary diagnosis will be more certain.
Is atopic dermatitis and contact dermatitis the same? What will be a positive finding of atopic dermatitis or contact dermatitis on skin test?
Trigger 3.
A paraclinical diagnostic procedure was done.
Skin test (patch test) was performed.
(+) delayed hypersensitivity (erythema, edema or papulovesicles)
Questions (as applicable):
1. Examine the result of the paraclinical diagnostic procedure and then interpret.
Significance or indications for skin (patch) test:
Can detect suspected allergens Can determine the presence of: Blastomycosis Tuberculosis Brucellosis Tularemia Echinococcosis Toxoplasmosis Histoplasmosis Lymphogranuloma venereum Mumps
Can detect suspected allergens
Can determine the presence of:
Significance or indications for burrow ink test:
Can detect mite, ova and feces of the Sarcoptes scabiei
Significance or indications for CBC:
Can detect eosinophilia and increased serum IgE levels as an indication for infection.
How do you interpret the presence of delayed hypersensitivity? Is this diagnostic of atopic dermatitis? Answer the question directly.
2. After the paraclinical diagnostic procedure, what is now your primary and secondary diagnosis? Why?
Primary diagnosis : Atopic Dermatitis Secondary diagnosis : Scabies
Primary diagnosis : Atopic Dermatitis
Secondary diagnosis : Scabies
You did not answer the question "Why?" If the delayed hypersentivity on skin test is a reliable diagnostic parameter of atopic dermatitis and since you are primarily considering atopic dermatitis, then you accept the skin test result as the diagnosis.
3. Do you need to firm up your diagnosis before you proceed to treatment? If yes, how? NO
The diagnosis is now quite certain because in the patch test that was performed, there was a positive delayed hypersensitivity which was manifested by swollen or reddened skin at the site of the patched skin after a given period of time and their mode of treatment is the same such as by giving topical agents to eradicate the causative agent and the preventive measures of controlling the pruritus.
4. Pretreatment Primary and Secondary Diagnosis:
Primary Diagnosis: Contact Dermatitis Secondary Diagnosis: Scabies Is contact dermatitis the same as atopic dermatitis? You kept on changing the terminologies!
Primary Diagnosis: Contact Dermatitis
Secondary Diagnosis: Scabies
Is contact dermatitis the same as atopic dermatitis? You kept on changing the terminologies!
5. Goals of Treatment
a. Eradication of the clinically evident pruritus. b. Relief of pain, itchiness and its accompanying signs and symptoms. c. Patient will survive long. d. Prevents recurrence of the skin problem. e. To have a patient who is satisfied, alive, happy and no medical suit.
a. Eradication of the clinically evident pruritus.
b. Relief of pain, itchiness and its accompanying signs and symptoms.
c. Patient will survive long.
d. Prevents recurrence of the skin problem.
e. To have a patient who is satisfied, alive, happy and no medical suit.
6. Plan of Management
What are the treatment options for atopic dermatitis? What are the definitive treatment? Steroids? Others? What are the treatment options for pruritus? Cold compresses? Wet dressing? corticosteroids? Compare them in terms of benefit, risk, cost, availability!
Trigger 4
The diagnosis of the patient's health problem is CONTACT DERMATITIS
1. Advice the patient and relatives on the pathophysiology of the disease. Use diagram.
EXPLANATION
The physiology of itching is not well understood, but it is presumed that various chemomediators (histamine, proteases, prostaglandins) liberated by a wide variety of stimuli and noxious agents (antigen) act on the fine, unmyelinated C nerve fibers near the basal portion of the epidermis to elicit the distinctive sensation of pruritus. Itch as well as pain sensation is transmitted along these small, slow-conducting sensory neurons in the spinal nerves to the spinothalamic tract and then to the thalamus and sensory cortex. It is not clear how scratching relieves itching, but a suggestion is that scratching disturbs the rhythm of afferent impulses travelling toward the spinal cord. Some authorities believe that itching is a subthreshold pain sensation, since itching cannot be elicited in analgetic skin and can be elicited in anesthetized skin (e.g., tabes dorsalis in which pain pathways are preserved). Other investigators regard itching as a distinct sensory modality arising from the outermost nerves of the skin, since removal of the epidermis and subepidermal nerve network abolishes itch (even though cutaneous pain remains) and morphine, while relieving pain, intensifies itching.
Pruritus is the outstanding sensory feature of many skin diseases, and the motor response it evokes, if not controlled leads to further damage of the skin surface, often with perpetuation and intensification of the symptom. This is clearly the case in patients suffering from allergic contact dermatitis, urticaria, and atopic eczema in which itching can be an all-consuming and debilitating symptom. Controlling the itching sensation by way of cold compresses, topical steroids, and oral antihistaminics is frequently crucial in bringing about a resolution of the eczematous response.
2. Advice the patient and relatives on screening of the disease.
The patient must know what causes his pruritus that leads to his skin problem as contact dermatitis. He must know what is contact dermatitis.
Contact dermatitis is an acute or chronic dermatitis that results from direct skin contact with chemicals or allergens. Four-fifths of such disturbance are due to excessive exposure to or additive effects of primary or universal irritants (eg, soaps, detergents, and organic solvents) and are called irritant contact dermatitis. Others are due to actual contact allergy such as poison ivy or poison oak. The most common dermatologic compounds causing allergic rashes include antimicrobials (especially neomycin), topical antihistamines, anesthetics, (benzocaine), hair dyes, preservatives (eg, parabens), latex, and adhesive tape.
Occasional exposure is an important cause of allergic contact dermatitis. Weeping and crusting are typically due to allergic and not irritant dermatitis, which often appears red and scaly. With widespread precautions being taken against HIV infection, contact dermatitis due to latex rubber in gloves and condoms is being seen more frequently.
Therefore, upon knowing these things by the patient, he can better prevent the occurrence and even the recurrence of the skin problem.
3. Advice the patient and relatives on early detection of the disease.
Any rash that is pruritus, the patient must be able to determine and recall of his previous activities whether he was exposed to some allergens, chemicals and etc that leads to the skin problems. Moreover, he must immediately avoid such exposure in order to prevent the occurrence of the skin problems.
REFERENCES
1) Fauci, et. al. Harrison's Principles of Internal Medicine, 14th ed. USA: McGraw-Hill Companies, Inc., vol. 1, 1998, pp. 294-328.
2) Fischbach, Frances Talaska. A Manual of Laboratory Diagnostic Tests, 3rd ed. Philadelphia: J.B. Lippincott Company, 1988.
3) FITZPATRICK TB et al (eds): Dermatology in General Medicine, 4th ed. New York, McGraw-Hill, 1993.
4) Friedman, Harold H. Problem-Oriented Medical Diagnosis, 6th ed. Boston: Little, Brown and Company Inc., 1996.
5) MURPHY GF (ed): Dermatopathology: A Practical Guide to Common Disorders. Philadelphia, Saunders, 1995.
6) Tierney, Lawrence M, et. al. Current Medical Diagnosis & Treatment. Stamford, Connecticut: Appleton & Lange, 1997.
Prepared by:
OBRIZ M. PAGLINAWAN PBL-III Obrizpeace@eudoramail.com
Additional Comments from Facilitator
Improve on the
Suggest review the "Management of a Patient" Framework.
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Comments, Questions, and Reactions from Readers
Obriz M. Paglinawan's Response and Reactions to R.O. Joson's Comments and Inquiries
PBL and Distance Learning on Skin and Soft Tissue Problems
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