Chronic or episodic severe itch is recurrent in atopic dermatitis (AD). Nonhistaminergic itch pathways are suggested to dominate in AD itch, contributing to an "itch-scratch-itch cycle" that prolongs and worsens itch, pain, and skin lesions. We hypothesized that nonhistaminergic neuronal sensitization contributes to itch in AD. Hence, we compared sensitivity with thermal, mechanical, and chemical pruritic stimuli in patients with AD and controls. The study comprised 25 patients with AD with chronic itch and 25 healthy controls. Questionnaires on itch characteristics were administered, and sensory tests were conducted intralesionally, extralesionally, and in homologous areas of controls. Thermal and mechanical quantitative sensory testing (QST) as well as histamine and cowhage provocations were performed. Subsequently, hyperknesis and vasomotor reactivity were assessed. Average itch and associated pain among patients with AD were 60.7 ± 4.3 and 39.7 ± 5.2 (VAS0-100), respectively. Patients experienced significantly higher itch from cowhage both intralesionally and extralesionally compared with controls, whereas histamine-evoked itch intensity was not significantly different between groups. No group differences were found for thermal quantitative sensory testings or pain evoked by itch provocations. Patients had decreased mechanical detection thresholds intralesionally and increased mechanical pain sensitivity intralesionally and extralesionally. Lastly, patients exhibited intralesional and extralesional hyperknesis before chemical itch provocations and augmented hyperknesis after itch provocations. Increased itch in response to cowhage (but not histamine) suggests nonhistaminergic pathway-specific itch sensitization in AD, whereas increased susceptibility to mechanically evoked itch and pain, particularly intralesionally suggests sensitization of mechanosensitive circuitry not normally associated with itch. Drugs targeting the nonhistaminergic (PAR2/TRPA1) itch pathway and itch sensitization are promising for treating AD itch.

Our results suggest that repeated field photodynamic therapy using topical MAL may prevent new AK in transplant recipients although further studies are needed.

The aim of this study was to evaluate the effect of photodynamic therapy with topical methylaminolevulinate for the treatment of basal cell carcinomas in a single dermatological department. Ninety patients (34.4% men and 65.6% women) with a total of 157 basal cell carcinomas (111 superficial, 40 nodular, 6 unknown) were treated. Primary endpoint was clinically observed recurrence verified by biopsy 3, 6 and 12 months after treatment, then once a year. Estimated patient recurrence rates were 7% at 3 months, 19% at 6 months, 27% at 12 months and 31% at 24 months. Patients aged over 60 years had significantly higher estimated recurrence rates compared with patients aged 60 years or under (at 12 months, 35% vs. 19%, p?=?0.01). Estimated recurrence rates for tumours was 4% at 3 months, 11% at 6 months, 16% at 12 months and 19% at 24 months. There were significantly higher estimated recurrence rates for nodular basal cell carcinomas compared with superficial basal cell carcinomas (at 12 months, 28% vs. 13%, p?=?0.008). In conclusion, photodynamic therapy is only appropriate for treatment of superficial basal cell carcinoma, and, age above 60 years and histology showing nodular basal cell carcinoma are independent risk factors for developing a recurrent basal cell carcinoma.

This report describes 9 patients who developed allergic contact dermatitis to methyl aminolevulinate used for photodynamic therapy (PDT). The risk of developing contact allergy to methyl aminolevulinate in PDT treated patients was calculated to 1% after an average of 7 treatments (range 2-21).