Erbium-doped yttrium aluminium garnet (Er:YAG) has a 2940 nm wavelength which is well absorbed by water. It is also absorbed by hydroxyapatite which makes it an ideal laser for tissue vaporization. In our clinic, we treated 398 patients with SH for the past 5 years with the variable long pulsed (VLP) Er:YAG (Fotona SP Dynamis, Ljubljana, Slovenia) setting, using 0.2 mm spot size, 5 J/cm2, VLP (1000 microsecond), 12 Hz. Patients had as few as 10 to as many as 40 SH that were treated in one session. The patient population consisted of 73% female to 27% male, with an age range of 35–77 years old. The patients received topical anesthetics preoperatively: a combination of benzocaine 20%, lidocaine 6%, tetracaine 4% for 30 minutes. Following that, a 0.2mm, very focused/defocused beam created a small crater consistent with the size of the sebaceous hyperplasia. The lesion was vaporized to the proper depth (~1mm), after which no remaining white-yellowish tissue was appreciated in the center of SH. It is very important to create a zone of vaporization of the exact same size as the SH lesion, since a larger crater may not completely heal and result in a pitted scar. Patients applied topical antibiotics daily for seven days and were advised to avoid sun exposure during the healing period. Patients were followed up between 1-36 months. Most lesions healed completely within 1-2 months and some had transient post-treatment erythema, which gradually completely improved (Figures 1 and 2). It is crucial to advise patients to minimize sun-exposure and encourage regular sunscreen use accompanied with usage of a wide bream hat to avoid post-inflammatory hyperpigmentation. We did not encounter any post-operative infection or persistent erythema. Patients should be advised with regards to potential adverse effects of treatment and proper consent should be obtained. If the white-yellow remnants within SH lesions are not completely vaporized, the SH can recur and may require an additional treatment.
PDL is a vascular-specific laser which will only non-specifically treat SH lesions through tissue destruction. Dermoscopic analysis of SH identify its fine vascular presentation which has been labeled as “crown vessels”. Considering the vascular specificity of SPDL, it can be deduced that, through using sub-millisecond pulses, the fine vessels will absorb the incoming laser energy and transmit the heat to the surrounding tissue, resulting in partial destruction of lesions. However, LPDL can cause deeper penetration into the tissue while less specifically heating the surrounding tissue, resulting in a less-than-ideal tissue destruction. The LPDL 5mm spot size is much larger than the average 1-3 mm SH lesions and can, consequently, treat the surrounding normal skin. It is also important to note that the aforementioned article on SPDL and LPDL followed patients only for a short time interval (8 weeks). CO2 laser in a tightly focused manner with proper settings can provide significant benefit in the treatment of SH. While CO2 laser can accurately destroy the lesions, it is associated with potential complications including scarring and pigment alterations. As most SHs are located on the face, some patients may prefer to keep their SH rather than face the more severe potential adverse effects of CO2 laser treatments. The use of ALA-PDT or curettage in combination with CO2 may be unnecessary, as the CO2 laser is an independently powerful method to completely treat SH lesions. Due to the aforementioned potential scarring and pigmentary abnormalities of the CO2 laser, the authors prefer the use of Er:YAG.