INTRODUCTION

Excimer light is a targeted phototherapy that uses 308-nanometer wavelength ultraviolet radiation to treat photoresponsive dermatoses such as psoriasis, vitiligo, and alopecia areata. Ideally, the minimal erythema dose (MED) should be determined to guide the initial treatment dose. However, due to convenience, estimation based on skin phototype is more commonly used.

OBJECTIVES

To determine the MED to excimer light in adult Filipinos using a visual erythema scale.

MATERIALS AND METHODS

A prospective interventional, cross-sectional study was conducted among adult Filipinos in a tertiary government hospital in the Philippines. Participants underwent phototesting with six incremental doses of excimer light. MED was defined as the lowest dose that produced uniform, well-defined erythema over the exposed area. Descriptive statistics summarized clinicodemographic data, MED, and adverse events. Fisher’s exact test assessed associations between MED, sex, and skin type.

RESULTS

A total of 149 adult Filipinos with Fitzpatrick skin types III to V were enrolled. MED values ranged from 150 to 400 mJ/cm2, with 200 mJ/cm² being the median and mode (33.56%). No association was found between MED and skin phototype. Sex correlated with MED, with females having higher MEDs than males.

CONCLUSIONS

The median MED was 200 mJ/cm2 in Filipino patients with skin types III to V. This may serve as the initial starting dose for phototherapy (except in vitiliginous skin). With the variation in the MED within the population, MED determination is still the ideal method to identify the most appropriate initial treatment dose.

Human ; Phototherapy ; Ultraviolet Therapy

Over-the-counter medications are readily available and convenient. However, intake may result in cutaneous adverse reactions such as acute generalized exanthematous pustulosis (AGEP). The need to differentiate the disease to similar pustular diseases such as pustular psoriasis and subcorneal pustular dermatosis is essential, to give way to proper patient management. Its appearance with psoriasis vulgaris is uncommon.

We highlight a 36-year-old Filipino female with a known case of psoriasis vulgaris, undergoing phototherapy with good compliance and response, who took one dose of mefenamic acid due to headache. Three days after, she presented with multiple, pin-point pustules surrounded by multiple, erythematous plaques and desquamative scales over the body, including non-psoriatic areas.

A skin punch biopsy on the left arm revealed that the epidermis shows a subcorneal pustule with spongiosis and focal vacuolar alteration at the base. The dermis showed edema and was infiltrated mainly of lymphohistocytes and eosinophils, consistent with acute generalized exanthematous pustulosis.

Treatment with cyclosporine of 3.0 mkd was given, with topical corticosteroids of clobetasol 0.05% ointment mixed with petroleum jelly. Gradual tapering every two weeks was done, with 90% improvement. Blood pressure monitoring was done while on treatment. No recurrence of pustular lesions seen thereafter.

Apart from NSAIDs, beta-lactams, and beta-blockers are common causes of AGEP. There have been few published case reports about concomitant psoriasis vulgaris and acute generalized exanthematous pustulosis. To ascertain the diagnosis among subcorneal pustular dermatosis, pustular psoriasis, acute generalized exanthematous pustulosis, clinical and histopathologic correlation should be done.

Human ; Female ; Adult: 25-44 Yrs Old ; Acute Generalized Exanthematous Pustulosis

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia affecting children 2-5 years old. The clinical presentation ranges from self-resolving localized disease to fulminant, fatal disseminated disease. While the most common presentation of LCH are small, translucent crusted papules on the trunk, intertriginous areas, and scalp, it may present as crusted plaques and alopecia. A 3-year-old male presented with a 4-month history of solitary, well-defined, hyperpigmented plaque with yellow-brown crust on the left parieto-occipital area of the scalp measuring 1.5 x 1.5 cm and a solitary, well-defined, hairless patch with areas of erythema on the left parieto-occipital area measuring 5.0 x 6.0 cm. Scalp biopsy revealed diffuse collection of lymphohistiocytes interspersed with distinct kidney bean-shaped cells. CD1a is positive for cells of interest. Skeletal survey revealed lytic lesions involving the skull, thoracic cage, spine, pelvis, and upper and lower extremities. The rest of the physical examination findings revealed lymphadenopathy, crackles, globular abdomen with right and left upper quadrant dullness. The patient had episodes of fever, difficulty of breathing, and abdominal pain. The patient received chemotherapy as multisystem LCH based on prednisone and vinblastine. Following 3 courses of chemotherapy, there is noted hair regrowth and sloughing off of crust.

Human ; Male ; Child Preschool: 2-5 Yrs Old ; Alopecia ; Histiocytosis, Langerhans-cell ; Vinblastine

Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma that may, although rarely, present as asymptomatic hypopigmented lesions. On the other hand, vitiligo is an autoimmune disorder characterized by asymptomatic depigmented patches. Few reports have documented both conditions occurring in a single patient, making this an intriguing diagnostic and management dilemma.

This is a case of a 26-year old female with a 10-year history of persistent hypopigmented, depigmented and erythematous patches and thin plaques [Figures 1a and 2a]. Histopathology showed epidermotropism of mononuclear cells on H&E stain [Figure 3] and a positive CD-3 stain for T cells, confirming mycosis fungoides [Figure 4b]. No evidence of lymphadenopathy and visceral involvement was found on both the chest and abdominal CT scans. The depigmented patches were likewise biopsied showing lack of Melan-A staining and absence of epidermal melanocytes, consistent with vitiligo [Figure 4a]. Final diagnoses were both mycosis fungoides, stage IB and vitiligo. The patient underwent narrowband UVB phototherapy and was started on topical corticosteroids [Figures 1b and 2b]. Improvement was evident over a three-month period, with body surface area decreasing from 77% to 46%. As the patient is young, has normal LDH levels, and shows no signs of extracutaneous disease, prognosis is promising.

This rare case of mycosis fungoides and vitiligo occurring together presents notable diagnostic and management challenges. Some studies hypothesize that the aberrant T cells involved in MF might contribute to the T cell-mediated destruction of melanocytes, similar to the mechanisms seen in vitiligo.

Human ; Female ; Adult: 25-44 Yrs Old ; Mycosis Fungoides ; Vitiligo ; Phototherapy

BACKGROUND

Narrow-band ultraviolet B (NB-UVB) phototherapy is a mainstay in the treatment of psoriasis, with dosage related to the minimal erythema dose (MED), with initial dose at 50-70%, followed by dose increments.

OBJECTIVE

To determine the MED of Filipino adult patients with psoriasis using NB-UVB phototherapy at a tertiary government hospital.

METHODOLOGY

This is an analytical, observational, cross-sectional study with prospective data collection among Filipino adults with psoriasis, at Dr. Jose N. Rodriguez Memorial Hospital and Sanitarium, from March 2023 to June 2024. Participants underwent MED determination using NB-UVB phototherapy cabinet. MED was defined as the square with definite redness, very light pink, or faintly detectable erythema over the entire exposed site after 24 hours. Clinicodemographic information were gathered and analyzed for possible associations with obtained MED.

RESULTS

Forty-eight participants were enrolled with MED as follows: 600 mJ/cm² (47.92%), 800 mJ/cm² (25%), 1000 mJ/cm² (12.50%), 1200 mJ/cm² (10.42%), and 400 mJ/cm² (4.17%). Age appeared to be directly proportional to MED dose (p-value =0.047). A statistically significant association of having lower MED values (p=0.017) were observed in patients with concomitant diabetes mellitus. Sex, Fitzpatrick skin type, psoriasis severity, and the body site used for testing, had no association with obtained MED values.

CONCLUSION

The median MED was 600 mJ/cm². Based on this, the suggested initial dosage of NB-UVB at 50-70% is 300-420 mJ/cm². These findings demonstrate that the current starting dose being used at DJNRMHS can either be maintained at 300 mJ/cm² or can be safely increased up to 420 mJ/cm².

Human ; Phototherapy ; Psoriasis