Urticaria and Drug Reactions Quiz

Urticaria (Hives)

• Erythematous wheals (raised, red skin)
• Types: spontaneous, cold, solar, delayed pressure, dermographism
• Acute (<6 weeks) or Chronic (>6 weeks)
• 50% idiopathic (no known cause)
• 40-50% autoimmune (linked to thyroid issues)
• Can be associated with Helicobacter pylori (H. pylori)
• Treatment:
  • First-line: antihistamine daily
  • Second-line: antihistamine four times a day
  • Third-line: Dupixent, Doxycycline, or Cyclosporine
  • Fourth-line: Allergist consultation, Zolair + cetirizine
  • Address any known triggers
  • Consider workup if angioedema or constitutional symptoms present

Common Drug Reactions

• Penicillin is a frequent culprit
• Bactrim is sometimes a severe reaction.
• Morbilliform rash (exanthema) often generalized on the trunk
• Typically appears 7-14 days after exposure

Red Man Syndrome

• Macular erythema (red rash)
• Starts on the back of the neck then spreads to trunk, face, and arms
• Pruritus (itching)
• Sometimes hypotension (low blood pressure)
• Treatment: antihistamines, topical steroids, slow infusion

Fixed Drug Eruption

• Round or oval patches at a fixed location
• Develops 1-2 weeks after first exposure
• More lesions can develop with repeated exposure
• NSAIDs (e.g., naproxen) are a frequent cause
• Rule out cupping

Photosensitivity Reactions

• UVA exposure can cause phototoxic reactions that mimic severe sunburns.
• Phototoxic reactions are not dependent on prior sensitization.
• NSAIDs and tetracyclines are potential causes for phototoxic reactions
• Hydrochlorothiazide, photosensitivity reactions present as photoallergic reactions where prior sensitization is a requirement
• Sulfa medications can also cause these kinds of reactions

Erythema Multiforme

• Minor: Associated with herpes simplex virus (HSV)
• No systemic symptoms, mild mucosal involvement
• Major: Associated with Mycoplasma or HSV
• Systemic symptoms, significant mucosal involvement.

Stevens-Johnson Syndrome & Toxic Epidermal Necrolysis (TEN)

• Drug eruption (rash) 7-21 days after taking medication
• Mucosal involvement & skin peeling , organ damage
• Common drugs: Allopurinol, sulfa drugs, anticonvulsants
• Severity classified based on body surface area affected (<10% = Steven Johnson, 10-30% = both, >30% = TEN)
• Prognosis depends on how quickly the offending drug is discontinued
• Treatment: Burn unit, gynecology, ophthalmology.

Pemphigus Vulgaris

• Autoimmune epidermal blistering disease in the spinosum layer.
• Blood work for desmoglein 1 and 3
• Treatment: Topical steroid, oral steroid, rituximab (for moderate to severe cases).

Bullous Pemphigoid (BP)

• Autoimmune subepidermal blistering disease at the dermal-epidermal junction (DEJ)
• Most common subepidermal autoimmune blistering disease
• Blisters are tense and do not break easily
• Neurological disorders (e.g., multiple sclerosis, stroke, bipolar disorder, and dementia) may be associated.
• Treatment: topical steroids for mild cases, oral steroids and rituximab for moderate/severe cases.

Dermatitis Herpetiformis

• Cutaneous manifestation of celiac disease
• Strong association with thyroid issues
• Grouped vesicular papules (itchy)
• Treatment: gluten-free diet, dapsone

Actinic Keratosis

• Small, dry, rough, erythematous, and flaky lesions
• Precancerous skin lesions caused by sun exposure.
• 10% can develop into squamous cell carcinoma (SCC)
• Treatment: Cryotherapy for a few lesions, 5-fluorouracil (5-FU) for multiple lesions (applied twice a day for 2-4 weeks)

Basal Cell Carcinoma (BCC)

• Most common skin cancer
• Rarely metastasizes
• Increased risk with sun exposure and genetic factors
• Superficial BCC: Affects the epidermis
• Treatment: Electrodesiccation and curettage (ED&C), 5-fluorouracil (5-FU), surgical excision, Mohs surgery

Squamous Cell Carcinoma (SCC):

• Second most common skin cancer
• High risk of metastasis
• Risk factors include: sun exposure, HPV, smoking, immunocompromised state.
• Treatment: In situ (epidermis): ED&C, topical 5-FU. In invasive (dermis): Excision, Mohs surgery

Melanoma

• Most common type is superficial
• Follow up with dermatologist every 3 months for the first 2 years of diagnosis.
• Dysplastic nevi: Mild to moderate — reassurance, Severe — MIS
• Important factor is depth in determining treatment
• Treatment varies based on depth (excision of melanoma in situ (MIS)) with 1 cm margins) or referral to general surgery in cases with deeper melanoma involvement.

Merkel Cell Carcinoma

• Rare, aggressive, and often large.
• Characteristic of coming from nowhere on the skin surface.
• Biopsy: Punch or shave.
• Referral to Oncology

Kaposi Sarcoma

• Rare skin cancer
• Associated with human herpesvirus 8 (HHV8).
• History of immunocompromised (or organ transplant) is often reported.

Melasma

• Symmetric, hyperpigmented macular patches.
• On sun-exposed areas (face, cheeks, forehead, neck).
• Often light brown or dark brown.
• Risk factors: Female, pregnancy, oral contraceptives
• Treatment: Hydroquinone, oral and topical steroids. Always wear sunscreen.

Post Inflammatory Hyperpigmentation (PIH)

• Hyperpigmented patches after skin injury or trauma.
• Common in Fitzpatrick skin types 4–6.
• Resolves within 6–12 months but Hydroquinone can speed the process up.
• Treatment: Sunscreen, Hydroquinone .

Acanthosis Nigricans

• Hyperpigmented, velvety patches or plaques.
• On neck, axilla, groin, and mammary areas.
• Linked to: Insulin resistance, obesity, metabolic disorders
• Treatment: Topical retinoids, keratolytics.

Vitiligo

• Depigmented macules and patches on the skin.
• Destruction of melanocytes, leading to depigmentation.
• Risk factors: Family history, thyroid issues.
• Treatment: Sunscreen, topical steroids, tacrolimus, topical Vitamin D,.

Lichen Sclerosus

• Atrophie papule with a pink rim
• Risk Factors: Autoimmune dysfunction, previous history of skin disease, and family history.
• Common on the genitals in women (10:1 ratio with men).
• Treatment: High-potency topical steroids, systemic therapies (e.g., oral steroids, methotrexate, cyclosporine), laser/PRP/surgery
• Biopsy for diagnosing and ruling out potential squamous cell carcinoma (SCC).

Pressure Wounds

• Bed sores due to prolonged pressure.
• Common locations: heels, sacrum, malleolus, greater trochanter
• Risk factors: Sensory deficits, age, poor nutrition, prolonged immobility.
• Stages: 1-4 (first is intact skin, 4th involves bone and muscle)
• Treatment: Wound care, moisture management, sepsis prevention.

Arterial Ulceration

• Punched-out appearance
• Severe pain with movement.
• Dependent rubor (redness when dependent).
• Pallor on elevation.
• Shiny atrophic skin, alopecia (hair loss).
• Diagnose with ankle-brachial index.
• No compression socks.

Venous Stasis Ulcers

• Most common vascular ulcer
• Usually in the lower leg, medial malleolus
• Risk Factors: Tobacco use, Diabetes.

Stasis Dermatitis

• Dry, pruritic, scaly, hyperpigmented rash on legs (due to venous insufficiency).
• Symptoms: Asymptomatic at first, then skin changes.
• Class 4 on spectrum: Hyperpigmentation, lipodermatosclerosis, atrophie blanche.
• Treatment: Compression stockings, (steroids for itching if no infection), vascular care referral

Shave Biopsy

• For lesions above the skin surface (skin tags, intradermal nevi, etc.)
• Epidermis and upper dermis are removed.

Punch Biopsy

• Goes deeper than a shave biopsy
• Used for lesions that require more tissue or for cosmetically sensitive regions and for lesions that are suspected to be on the blood thinners.
• Epidermis and dermis are removed.

Cryotherapy

• Non-invasive (uses cryogen)
• Treatment for benign and premalignant skin lesions.
• Two freeze-thaw cycles.

Test your knowledge on urticaria, common drug reactions, and conditions like Red Man Syndrome. This quiz covers the types, causes, treatments, and symptoms associated with these dermatological issues. Perfect for students and professionals in the medical field.