Dermatology

Psoriasis severity and PASI scoring

Psoriasis severity assessment runs on the Psoriasis Area and Severity Index (PASI), and it has for decades. PASI breaks the body into four regions (head, trunk, upper limbs, lower limbs), scoring each for erythema, induration, and desquamation on a 0 to 4 scale, then weighting by the percentage of surface area involved. The total runs from 0 to 72. It is cumbersome. It takes practice to do it quickly and consistently. But it is still what regulators want to see. PASI 75 (a 75% reduction from baseline) was the original gold standard endpoint that got the first TNF inhibitors approved. PASI 90 and PASI 100 followed as treatment targets got more ambitious, especially with IL-17 inhibitors like secukinumab and ixekizumab and IL-23 inhibitors like guselkumab and risankizumab, where PASI 90 response rates now push past 70 to 80% in clinical trials. The DLQI (Dermatology Life Quality Index) sits alongside PASI in most studies and in many payer prior authorization forms, because a 90% improvement in skin clearance does not matter much if the patient still cannot sleep or wear short sleeves. The real shift in the last few years has been toward treat-to-target, borrowed from rheumatology, where a target PASI response (usually PASI 90 or absolute PASI below 3) is set at the start of treatment and therapy is escalated or switched if that target is not met within a defined window, typically 12 to 16 weeks. That approach has changed how quickly patients move from topical therapy to phototherapy to systemic agents to biologics. And it has made accurate PASI scoring at every visit more than just academic. The DLQI itself has known structural limitations. Questions about work, leisure, and sexual relationships are often marked "Not relevant" by elderly or inactive patients, and because "Not relevant" scores as 0, the total can underestimate true disease burden. This has driven research into alternative scoring methods. The DLQI-R (revised scoring), which adjusts the total for the number of "Not relevant" responses, and the DLQI-NS (2024), which adds a "moderate" option to capture intermediate impact, are two of the most studied modifications. Neither has replaced the original in routine practice or regulatory use, but both reflect a growing recognition that the standard DLQI, for all its strengths, does not fit every patient equally well.

Atopic dermatitis severity scoring with EASI and SCORAD

Atopic dermatitis has its own severity ecosystem, and it has expanded fast. The Eczema Area and Severity Index (EASI) works similarly to PASI but scores erythema, edema/papulation, excoriation, and lichenification rather than the psoriasis triad. SCORAD adds subjective symptoms (pruritus and sleep loss) on a visual analog scale, which some clinicians find more reflective of real-world disease burden. The POEM (Patient Oriented Eczema Measure) is a 7-item patient-reported questionnaire that captures symptom frequency over the past week. It correlates reasonably well with EASI and is much faster to administer in clinic. The real challenge in atopic dermatitis scoring is that pediatric patients dominate the population, and children cannot always articulate itch severity or sleep disruption the way adults can. The ISAAC questionnaire was developed partly to address this in epidemiologic studies, while the ADASI and TIS (Three Item Severity) scores offer simpler alternatives for rapid assessment in younger children. The arrival of dupilumab in 2017 changed the treatment landscape significantly. It was the first biologic approved for moderate to severe atopic dermatitis, blocking IL-4 and IL-13 signaling through the shared IL-4 receptor alpha subunit. EASI 50, 75, and 90 response rates in the LIBERTY AD trials ran around 65, 44, and 22% at 16 weeks against 22, 12, and 2% for placebo. Since then, tralokinumab (anti-IL-13) and lebrikizumab (also anti-IL-13, with a different binding profile) have joined the field, and topical JAK inhibitors like ruxolitinib cream and delgocitinib have added non-steroidal options for milder disease. The scoring landscape has had to keep pace with a treatment landscape that barely resembles what it was ten years ago.

Melanoma staging and prognostic nomograms

Melanoma staging is governed by the AJCC 8th edition, and the changes from the 7th edition were not small. The T category now incorporates Breslow thickness in finer increments: less than 0.8 mm is T1a if non-ulcerated and T1b if ulcerated. The old 1.0 mm threshold is gone. Between 0.8 and 1.0 mm is T1b regardless of ulceration status. T2 starts at 1.01 mm. T3 at 2.01 mm. T4 at 4.01 mm. Ulceration upstages within each T category. The N category now accounts for microsatellites, satellite lesions, and in-transit metastases as N1c, N2c, or N3c depending on nodal burden. The M category distinguishes M1a (distant skin, soft tissue, or nodal involvement), M1b (lung), M1c (non-CNS visceral), and M1d (CNS). Each of those M subcategories carries a different prognosis, and the arrival of effective immunotherapy (anti-PD-1 agents like pembrolizumab and nivolumab, plus the combination of nivolumab and ipilimumab) and targeted therapy (BRAF/MEK inhibitors for V600-mutant tumors) has shifted survival curves dramatically even for M1d patients. The MSKCC melanoma nomogram remains a useful tool for estimating individualized recurrence risk after definitive surgical treatment. It incorporates age, Breslow thickness, ulceration, mitotic rate, and sentinel lymph node status into a 5-year and 10-year estimate. The nomogram was derived from over 8,000 patients at a single high-volume center, so calibration may shift in community practice, but it gives patients and clinicians a concrete number to anchor surveillance decisions and adjuvant therapy discussions. Sentinel lymph node biopsy itself has been the subject of ongoing debate since the MSLT-II trial showed that completion lymph node dissection after a positive sentinel node did not improve melanoma-specific survival compared to active surveillance with serial nodal ultrasound. That trial changed practice. The nomograms and staging tools here reflect that change.

Non-melanoma skin cancer risk stratification

Non-melanoma skin cancer is the most common malignancy in the United States by a wide margin. Basal cell carcinoma alone accounts for roughly 3 to 4 million cases per year. Squamous cell carcinoma is less common but carries real metastatic potential, particularly when it arises in high-risk locations like the lip, ear, and genitalia, or in immunosuppressed patients like organ transplant recipients. The NCCN guidelines stratify BCC and SCC into low-risk and high-risk categories based on size, location, borders, primary versus recurrent disease, immunosuppression, prior radiation, and perineural involvement. High-risk SCC has a 5-year risk of nodal metastasis anywhere from 5 to 30% depending on how many risk factors cluster together. Staging follows the AJCC 8th edition for cutaneous SCC, which is distinct from the SCC staging for other head and neck sites, and the Brigham and Women’s Hospital (BWH) alternative staging system, which some argue discriminates better between T2a and T2b tumors. On the treatment side, Mohs micrographic surgery offers the highest cure rates for high-risk and cosmetically sensitive tumors. Electrodesiccation and curettage, standard excision, topical imiquimod and 5-fluorouracil, photodynamic therapy, and radiation all have roles depending on tumor subtype, location, patient age and preference, and functional status. For advanced BCC and SCC that are not surgically resectable, hedgehog pathway inhibitors (vismodegib, sonidegib) and anti-PD-1 immunotherapy (cemiplimab for SCC, recently approved for BCC as well) have expanded the options considerably.

Cutaneous adverse drug reaction grading

Cutaneous adverse drug reactions range from mild morbilliform exanthems that resolve with antihistamines and discontinuation of the offending drug to life-threatening conditions like Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS). The distinction matters because the mortality of SJS and TEN runs from 5 to 30% depending on the extent of epidermal detachment, age, and comorbidities, while DRESS carries a different risk profile centered on eosinophil-mediated organ injury, particularly hepatitis, myocarditis, and pneumonitis. SCORTEN is the validated severity-of-illness score for SJS/TEN, using seven parameters assessed within the first 24 hours of admission: age over 40, heart rate over 120, active malignancy, epidermal detachment over 10% of BSA, serum urea over 10 mmol/L, serum bicarbonate under 20 mmol/L, and serum glucose over 14 mmol/L. The predicted mortality ranges from 3.2% with zero or one factor up to 90% with five or more. DRESS diagnosis and severity grading follow the RegiSCAR criteria, which assign points for fever, lymphadenopathy, eosinophilia, atypical lymphocytosis, skin involvement extent and morphology, organ involvement, and clinical course. The RegiSCAR severity score classifies DRESS as probable, definite, or no, and a separate severity grading system (mild, moderate, severe) guides the decision to use systemic corticosteroids, steroid-sparing agents like cyclosporine, or supportive care alone.

Burn assessment and fluid resuscitation

Burn assessment in dermatology and emergency medicine follows the same rules as in trauma surgery, because a burn is trauma first. The Rule of Nines and the Lund-Browder chart are the standard tools for estimating total body surface area involvement, and that estimate drives fluid resuscitation volume through the Parkland formula and the modified Brooke formula. Full-thickness burns (third degree) require excision and grafting, while deep partial-thickness burns (second degree) may heal with appropriate wound care or require excision depending on depth assessment and healing trajectory. The revised Baux score (age plus percentage TBSA burned plus 17 if inhalation injury is present) predicts mortality and guides triage decisions, especially in elderly patients where even moderate burns carry disproportionate risk. ABSI adds sex and inhalation injury as separate variables and may discriminate better at the extremes of age. The ABA burn center referral criteria lay out absolute and relative indications for transfer including full-thickness burns over 10% TBSA, burns involving the face, hands, feet, genitalia, perineum, or major joints, electrical or chemical burns, inhalation injury, burns in patients with significant comorbidities, and concomitant trauma where the burn injury poses the greater immediate risk. For smaller burns that do not require transfer, the Lausanne burn depth classification and the Vancouver Scar Scale for long-term scar outcomes give clinicians structured tools for assessing healing quality and planning reconstructive intervention.

Hidradenitis suppurativa staging and acne grading

Hidradenitis suppurativa and acne vulgaris both rely on severity staging that guides treatment intensity. Hurley staging for hidradenitis suppurativa is a three-stage system based on the presence and extent of abscesses, sinus tracts, and scarring, without reference to the number of lesions or anatomic distribution. It is simple and widely used but it lacks granularity for treatment response monitoring. The Sartorius score adds lesion counts and anatomic site involvement and is more sensitive to change over time, making it the preferred tool for clinical trials. The HS-Physician Global Assessment (HS-PGA) offers a six-point scale that balances clinical utility with discriminant validity. Treatment for HS ranges from topical clindamycin for mild disease through adalimumab (the only FDA-approved biologic for HS) and surgical deroofing or excision for moderate to severe disease, with a growing interest in IL-17 inhibition (secukinumab, bimekizumab) based on positive phase 3 trial data. Acne vulgaris grading traditionally used the Leeds acne grading technique, which photographs and scores the face, chest, and back separately. The Investigator’s Global Assessment (IGA) is simpler and more practical for everyday use, rating acne from clear (0) to severe (4). The IGA is the standard endpoint in acne clinical trials, with IGA success typically defined as a 2-grade reduction from baseline to clear or almost clear.

Cutaneous T-cell lymphoma staging

Cutaneous T-cell lymphoma (CTCL), particularly mycosis fungoides and the leukemic variant Sezary syndrome, is staged using the TNMB (tumor, node, metastasis, blood) classification adopted by the ISCL and EORTC. The modified staging system incorporates skin involvement extent (patches, plaques, tumors, erythroderma), lymph node status (clinical and pathologic), visceral involvement, and blood tumor burden (Sezary cell count or flow cytometry). Stage IA disease (limited patches or plaques covering less than 10% of the BSA) carries an excellent prognosis with median survival exceeding 30 years, while stage IV disease with visceral involvement has a median survival closer to 2 to 3 years even with modern therapies. The mSWAT (modified Severity Weighted Assessment Tool) quantifies skin disease burden by multiplying the percentage body surface area of patches, plaques, and tumors by severity weights of 1, 2, and 4 respectively. It is the standard skin assessment tool in CTCL clinical trials. Treatment follows a skin-directed approach in early stages (topical steroids, topical nitrogen mustard, phototherapy, localized radiation) and shifts to systemic therapy in advanced stages (interferon, retinoids, histone deacetylase inhibitors like vorinostat and romidepsin, brentuximab vedotin for CD30-positive disease, mogamulizumab for CCR4-positive CTCL, and allogeneic stem cell transplantation in eligible patients).

Alopecia areata and vitiligo assessment

Alopecia areata assessment has been formalized through the SALT (Severity of Alopecia Tool) score, which divides the scalp into four quadrants and estimates the percentage of hair loss in each to derive a total score from 0 (no hair loss) to 100 (complete scalp hair loss). SALT scores of 50 or higher are generally considered severe and warrant consideration for systemic therapy. The SALT score is the primary endpoint in alopecia areata clinical trials, with SALT 20 (20% or less scalp hair loss) increasingly accepted as a clinically meaningful treatment response. The FDA approval of baricitinib, an oral JAK inhibitor, for severe alopecia areata in 2022 marked the first systemic therapy specifically approved for this condition. The BRAVE-AA1 and BRAVE-AA2 trials showed SALT 20 achievement in roughly 35% of patients on 4 mg daily at 36 weeks versus 5% on placebo. Other JAK inhibitors, including ritlecitinib and deuruxolitinib, have followed with positive trial results. Vitiligo assessment uses the VASI (Vitiligo Area Scoring Index) and the simplified VETF (Vitiligo European Task Force) score, which separately assess extent, stage, and progression of depigmentation. Ruxolitinib cream became the first FDA-approved treatment for nonsegmental vitiligo in 2022 based on the TRuE-V program, which showed significant repigmentation, particularly on the face, at 52 weeks.