Keloids – pathogenesis and treatment

Keloids are tumors formed as a result of hyperproliferation of fibroblasts. They appear mostly in places of an injury but they can also appear without any specified reasons. Areas especially vulnerable to kleoids formation are neck and chest skin. There are also special individual predispositions for prevalence of the tumor. The black race is more often affected by Keliods. (4)

 The highest probability of keloids formation concerns the burn wounds, but they may also form from the post surgery wounds, post acne wounds or post-Herpes-Varicella-Zoster infection. The formation of keloids after kerakethomy or LASIK  (laser-assisted in situ keratomileusis) in astigmatism treatment, usually occurs with already coexisting keloids.(5)

On the basis of the immounohistochemical analysis, Japanese scientists proved the accelerated expression of mRNA Wnt5a and Wnt2 in keliods’ fibroblasts cell lines in comparison with the normal fibroblasts.(3) The results were concordant with RT-PCR and Western Blot methods analysis.

 This discovery established a potentional function of Wnt (wingless) signaling pathway in keloids formation pathogenesis. The Wnt pathway play various part in cell cycle including proliferation induction, survival, differentiation, apoptosis and migration of cells.

Unfortunately the therapy of keloids is quite hard. Surgical excision of keloids may lead to the formation of new ones due to the fact that the irritation of sensible skin tissues is an impulse to proliferation of fibroblasts at  that place. However, it seems that the authors of a new publication in American Society for Dermatologic Surgery discovered a new way to cope with the failure of surgical keloid treatment. (1) They described a new standardized adjuvant  therapy. They made the first steroid injection right after removal of the suture and then they repeat the procedure 4 times in the intervals of 2 weeks. Additionally every post surgical wound was applied twice a day with a self-administered steroid ointment for the 6 months after the suture removal.

The methods used so far to keloid therapy were onion extract and collagen ointment, but they had to be administered regularly for a long time. Another methods include: injections with triamcynolon, gamma or alpha interferon or kolchicin. But actions not following the sterility stands may lead to contamination of scars e.g. by nontuberculosis Mycobacterium (6), what may lead to ulceration of keloids and complication of healing process requiring additional combined antibiotic therapy with Amikacin and Clarithromycin for about 4 months.

In the therapy of smaller and new-formed keloids it is also common to use occlusive bands  with fluoride steroids or heparin and their derivate.  The effectiveness of the radiotherapy is not clearly proved. The interesting possibility in keloid treatment is laser treatment. Pulsed dye laser therapy seems to have good prospects for young patients especially in connection with the corticosteroids and 5-fluorouracil therapy.(2)


Written by: Magdalena Chorążka




Source:
1. A New Uniform Protocol of Combined Corticosteroid Injections and Ointment Application Reduces Recurrence Rates After Surgical Keloid/Hypertrophic Scar Excision. Hayashi T and all. Dermatol Surg. 2012 Jan 24. doi: 10.1111/j.1524-4725.2012.02345
2. Are there any good treatment for keloid scarring after sternothomy? Pai VB., Cummings I. Interact Cardiovasc Thorac Surg. 2011 Oct;13(4):415-8. Epub 2011 Jul 7. Review.
3. Characterisation of Wnt signaling pathway in keloid pathogenesis. Ueno T. and all. J Nihon Med .Sch. 2011;78(6):405-6.
4. Choroby skóry. Jabłońska S. Chorzelski T. PZWL, 340-341
5. Conventional Epi-LASIK and Lamellar Epithelial Debridement in Myopic Patients with Dermatologic Keloids, Jun Yong Lee and all, Korean J Ophthalmol. 2011 June; 25(3): 206–209
6. Mycobacteria in keloid. Ashish Singh, S. Ambujam, Shailesh Kumar and S. Uma Devi Lung India. 2011 Oct-Dec; 28(4): 320–321.


Want to know more about Keloid? Watch on medtube.net “Skin – keloid, self-learning module, Cell Injury, Inflammation and Repair

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