Urticaria and Drug Reactions

Urticaria

• Erythematous wheals are a characteristic symptom
• Types include spontaneous, cold, solar, delayed pressure, and dermographism
• Acute urticaria lasts less than 6 weeks
• Chronic urticaria lasts more than 6 weeks
• 50% of cases are idiopathic (no identifiable cause)
• 40-50% are autoimmune, sometimes related to thyroid issues or H. Pylori
• Treatment initially involves antihistamines, and may progress to more potent medications like Dupixent, doxycycline, or cyclosporine; further testing and specialist consultation may be necessary

Common Drug Reactions

• Penicillin is a frequent culprit
• Bactrim can cause severe reactions
• Morbilliform rash/exanthem is commonly generalized on the trunk
• Symptoms typically appear 7-14 days after drug exposure

Fixed Drug Eruptions

• Characterized by round or oval patches that remain at the same location after exposure
• Frequently associated with NSAIDs, particularly naproxen

Red Man Syndrome

• Occurs due to vancomycin administration
• Macular erythema develops on the back of the neck and spreads to the trunk, face, and arms
• Pruritus (itching) and hypotension are sometimes present
• Treatment typically entails antihistamines and slowing down the infusion

Erythema Multiforme

• Minor cases are associated with HSV; no systemic symptoms, and minimal mucosal involvement
• Major cases are associated with Mycoplasma and HSV; systemic involvement and significant mucosal involvement

Stevens-Johnson Syndrome & Toxic Epidermal Necrolysis (TEN)

• Eruption typically appears 7-21 days after medication use
• Mucosal involvement and skin peeling are common
• Drugs associated with this include allopurinol, sulfa drugs, and anticonvulsants
• Severity categorized by body surface area affected; <10% for Stevens-Johnson, 10-30% both, >30% for TEN
• Prognosis impacted by prompt discontinuation of the responsible drug
• SCORTEN is a prediction tool for mortality risk

Pemphigus Vulgaris

• An autoimmune epidermal blistering disorder affecting the spinosum layer
• Diagnostic evaluation should also include blood work

Bullous Pemphigoid

• Autoimmune subdermal blistering disorder at the dermal-epidermal junction
• Commonly associated with neurological disorders, such as multiple sclerosis, stroke, bipolar disorder, dementia, and Parkinson's disease

Dermatitis Herpetiformis

• Cutaneous manifestation of celiac disease, commonly associated with HLA-DQ2 and thyroid disease
• Characterized by itchy, grouped vesicular papules

Actinic Keratosis

• Small, dry, rough, erythematous, and flaky lesions
• Often precancerous, linked to sun exposure
• Treatment options include cryotherapy or topical 5-fluorouracil (5-FU) for multiple lesions

Basal Cell Carcinoma

• Most common skin cancer, rarely metastasizing
• Increased risk with sun exposure and genetic predisposition
• Superficial BCC affects the epidermis while nodular BCC is red, raised, and scaly with telangiectasias
• Treatment options include electrodesiccation and curettage, 5-FU, or Mohs surgery for the nodular type

Squamous Cell Carcinoma

• Second most common skin cancer, particularly dangerous due to high metastasis rates
• Risk factors include sun exposure, HPV, smoking, immunocompromised status; lichen sclerosis, or chemical exposure
• Treatment depends on the stage (in situ vs. invasive) and may involve surgical excision, topical 5-FU, or Mohs surgery

Melanoma

• Most common type is superficial; follow-up exams every 3 months essential for the first two years
• Dysplastic nevi (moles) often provide clues to early diagnosis, but severity hinges on depth
• Depth of melanoma is the most important factor in prognosis/treatment, requiring wider excision

Merkel Cell Carcinoma

• Rare, aggressive skin cancer often presenting as a large nodule
• Diagnosis is typically made via biopsy

Kaposi's Sarcoma

• Rare cancer affecting blood vessels or lymphatic vessels
• Often associated with immunocompromised states or organ transplantation

Melasma

• Symmetrical hyperpigmented macular patches
• Common in women, particularly during pregnancy or oral contraceptive use
• Treatment focuses on reducing UV exposure and lightening treatments

Post-Inflammatory Hyperpigmentation

• Hyperpigmented macules/plaques that show up after injury
• Skin trauma and inflammation are frequent causes
• Typical timeframe for resolution is 6-12 months Treatment includes sunscreens and topical lightening agents (hydroquinone).

Acanthosis Nigricans

• Hyperpigmented, velvety patches, often associated with insulin resistance, obesity, and metabolic disorders
• Treatment often involves targeting underlying conditions and managing symptoms with topical retinoids or keratolytics

Vitiligo

• Depigmented macules/patches
• Linked to thyroid conditions or family history
• Treatment focuses on sunscreen and topical agents (steroids, tacrolimus, vitamin D)

Lichen Sclerosus

• Ivory white, itchy, atrophic skin papules with a pink rim
• Risk factors include autoimmune dysfunction, skin disease, family history, and thyroid history
• Commonly seen on labia minora in women

Pressure Wounds/Ulcers

• Develop due to compression or pressure on bony prominences
• Risk factors include sensory impairment, advanced age, malnutrition, and prolonged immobility
• Staging categorizes the depth of involvement (intact skin to damage impacting bone and muscle)
• Management focuses on prevention (pressure relief), and treatment (depends on stage).

Arterial Ulcers

• Ulcers have a punched-out appearance with severe pain, possibly accentuated with movement
• Diagnostic tools include ankle-brachial index (ABI) measurements, often necessitating an assessment of blood flow

Venous Ulcers

• Common vascular condition frequently occurring on the medial malleolus of the lower leg
• Associated risk factors such as smoking and diabetes play significant roles

Stasis Dermatitis

• Chronic inflammatory skin condition due to venous insufficiency; usually presents as scaly, hyperpigmented rash
• Diagnosis requires assessment of skin and history; venous ulceration is usually present
• Treatment protocols include wound care, elevation, compression therapy, and treatment of associated factors
• Treatment includes compression stockings, especially for durations exceeding three months for optimum results

Shave Biopsy and Punch Biopsy

• Shave biopsies are used for skin lesions above the skin's surface
• Punch biopsies are used for skin lesions beneath the surface skin